DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on October 20, 2025 has been entered.
Response to Amendment and Status of Claims
Applicant’s amendments to the claims, filed October 20, 2025, are acknowledged. Claims 80-81 are newly added.
Claims 1-2, 7-13, 18-19, 21, 44-45, 53-54, 56-59, 62, 65-69, 72-75 and 77-81 are pending and currently considered in this office action.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on October 20, 2025 was filed after the mailing date of the Final Rejection on June 18, 2025. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 7-13, 18-19, 21, 44, 62, 74 and 79-81 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided), Abenthung850 (previously cited, US 20140238850 A1) and Li2020 (previously cited, “Pressureless two-step sintering of ultrafine-grained tungsten”).
Regarding Claim 1, Abenthung909 discloses a method of forming a metal alloy (Abstract), comprising:
sintering particles comprising molybdenum (Mo) and chromium (Cr) to produce the metal alloy (para. [0019] and para. [0041], wherein metal powder is Mo alloy and comprises Cr; para. [0021], wherein powder is sintered), wherein:
Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of Cr would comprise Mo in an amount of 56-99at%);
the particles comprise an average size of 0.5-10um (para. [0019]); wherein
for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (para. [0021]; sintering in a vacuum would comprise an applied pressure of less than 2MPa; additionally, Abenthung909 does not disclose a pressure during sintering and therefore one of ordinary skill in the art would appreciate the sintering to occur without applied pressure); wherein
the sintering results in the metal alloy having a relative density in an amount of at least 98% (Abstract, 99%); and
wherein the metal alloy comprises an average grain size of less than 100um (Abstract; see also para. [0040], an average grain size of less than 100um reads on the claimed ‘grains having sizes greater than or equal to 1000 nm’).
Regarding the particle size of the sintering particles, Abenthung909 does not expressly disclose wherein at least 75vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, it would be obvious that an average particle size (at least 50%) of 0.5-10um overlap the claimed range of at least 75% of a total particle volume comprising maximum cross-sectional dimensions of about 1 micrometer to 1mm. Further it would be obvious to comprise 75vol% of the total particle volume within the desired range of Abenthung909 (up to 10um), and therefore at least 75% of the total particle volume within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Abenthung909 is silent towards the grain size of the sintering particles, and does not disclose wherein the particles comprise nanocrystalline particles are those with a grain size smaller than or equal to 100nm.
Wu teaches a spherical molybdenum alloy powder produced by high-energy ball-milling for molybdenum alloy target sintering, wherein the powder comprises a complete solid solution of molybdenum and the alloying element and a nanoscale internal crystallite size, thereby facilitating improved densification, reduced porosity and enhanced elemental and microstructural uniformity (Abstract; para. [0007]). Wu teaches an average grain size of 10um or less and an internal crystallite size of 30nm or less (Abstract; para. [0008], D50 of 2.58-2.634um and D10-D90 of 1.306-5.852um; para. [0041], crystal size of 13.56nm and particle size D50 of 2.63um; see also para. [0080], crystal sizes ranging from 13.68-23.23nm after ball-milling; see also Fig. 8 and Fig. 9, crystal grain sizes less than 30nm after ball milling).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a crystal grain size of 30nm or less, such as by high-energy ball milling, as taught by Wu, for the invention disclosed by Abenthung909, in order to comprise to facilitate improved densification, reduced porosity and enhanced elemental and microstructural uniformity through the complete solid solution of molybdenum and the alloying element (see teachings above).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP § 2144.05.I.
Abenthung909 discloses wherein sintering temperature may be as low as 1600C, but does not disclose wherein 1600C achieves a density of greater than 98% for a sintering particles size of 1um-1mm as claimed.
Further, Abenthung909 is silent towards sintering time.
Abenthung850 teaches a Mo-Cr sintering particle, wherein a particle may have a size of 1.5-3um, wherein sintering obtains a density of up to 99.5%, and wherein a pressureless sintering temperature is based on a homologous temperature of 0.6-0.9 (para. [0014]; para. [0027]; para. [0038]; para. [0036]). One of ordinary skill in the art would appreciate that the melting point for a 56at% Mo and 44at% Cr (Mo-30wt%Cr) is about 2175C, and therefore the 0.6-0.9 homologous temperature range would be 1305-1957C (see para. [0041] of Abenthung909 wherein Cr may be included up to 30wt%; 2175C melting point obtained from Cr-Mo phase diagram). One of ordinary skill in the art would appreciate that the lower temperature disclosed by Abenthung909 (1600C), appears to be approximately the 0.6 homologous temperature for pure Molybdenum.
Abenthung850 teaches wherein a sintered density of up to 99.5% reduces defects in subsequent deformation processes while balancing for coarse grain formation (para. [0038]).
Further, Li2020 teaches wherein a pressureless, reduced temperature, two-step sintering process of 11 hours achieves 99% theoretical density, mitigates grain coarsening, and significantly lowers required sintering temperatures as compared to normal sintering (Table 1, wherein 99.6% density is achieved at 1600C for 3 hours for normal sintering, and 99.1% density is achieved at 1450C (1hr) and 1350C (10hrs) for two-step sintering – 11 hours total).
While Li2020 is directed to tungsten, one of ordinary skill in the art would appreciate the applicability of Li2020 to Mo materials and those Abenthung909 because Abenthung909 teaches pressureless sintering for Mo materials which may comprise W (see para. [0041] of Abenthung909; see also Abethung850 teachings for pressureless sintering of Mo and W alloys), both W and Mo are refractory metals and 6b metals which alloy with each other, and Li2020 does not appear to suggest that the two-step process is limited to W or pure W.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have alternatively used a 0.6-0.9 homologous temperature as the pressureless sintering temperature for the Mo-Cr alloy of Abenthung909, as taught by Abenthung850, including a pressureless sintering temperature as low as 1305C for the Mo-30wt% Cr alloy of Abenthung909 (see analysis above), and further an 11 hour two-step pressureless sintering process such that the sintering temperature is further reduced (less than 1600C), as taught by Li2020, and therefore comprised a sintered density up to 99.5%, which reads on the claimed 98% or more, as taught by Abenthung850, for the invention disclosed by Abenthung909. One would be motivated to do this because the homologous temperature is based on the absolute melting point of the material and therefore this sintering temperature is more tailored to the alloy composition (see para. [0029] of Abenthung850), and in order to lower the sintering temperature while achieving up to 99.5% theoretical density, thereby mitigating significant or unwanted grain coarsening while also maximizing reduction of defects in any subsequent deformation processes (see teachings above by Li2020 and Abenthung850).
Therefore, Abenthung909, Abenthung850 and Li2020 disclose wherein the sintering temperature is 1600C or less for 99% of sintering time, wherein sintering is less than 24hours (11 hours), and a density of 98% or greater is formed as a result of sintering the particle sizes disclosed by Abenthung909 and at temperatures of 1600C or less, as taught by Abenthung850.
Additionally, the particle composition (Mo-Cr, disclosed by Abenthung909), particle size (1-10um, disclosed by Abenthung909), and grain size (as 30nm or less, taught by Wu), are the same as claimed (Mo-Cr with at least 55at% Mo, 1um-1mm particle size, and grain size of 100nm or less), and it would be expected that the particles achieve the same densification of 98% or greater for the same pressureless sintering temperatures and times (1600C or less, see teachings by Abenthung850 and Li2020; less than 24 hours, see teaching by Li2020).
When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 7, Abenthung909 discloses further comprising a third element (para. [0041], wherein multiple additional alloying elements may be included).
Regarding Claim 8, Abenthung909 discloses wherein the third element present in the metal alloy is in an amount from 0.5-30wt%, which overlaps the claimed range of 0.5-40at% (para. [0041], wherein 0.5-30wt% of Cr, W, or Ta may be included). For example, a Mo alloy comprising 25%Cr and 5wt% W would comprise 38.8at% Cr, 2.2at% W and 59at% Mo, and a Mo alloy comprising 25wt%Cr, 3wt%W and 2wt% Ta would comprise 38.8at% Cr, 1.3at% W, 0.9at%Ta and 59at% Mo.
Regarding Claim 9, Abenthung909 discloses wherein the second element may be Cr and the third element may be W, and therefore discloses elements which exhibit the claimed miscibility gap (para. [0041], wherein Mo is alloyed with Cr (second element) and may also be alloyed with W (third element)). One of ordinary skill in the art would appreciate that Cr and W exhibit a miscibility gap, as seen on the binary phase diagram of W and Cr).
Regarding Claim 10, Abenthung909 discloses wherein the third element is tungsten (see para. [0041], wherein 0.5-30wt% of Cr (second element) and additionally Ta and/or W (third element) may be included).
Regarding Claim 11, Abenthung909 discloses wherein the third element is tantalum (see para. [041], wherein 0.5-30wt% of Cr (second element) and additionally Ta and/or W (third element) may be included).
Regarding Claim 12, Abenthung909 discloses wherein the Mo alloy may comprise up to 30wt% Cr (para. [0041]), and one of ordinary skill in the art would appreciate that a Mo alloy comprising 12.5at% or less Cr (7.2wt% or less) would have a melting point of 2500C or greater (based on the binary diagram of Mo an Cr), as claimed.
Regarding Claim 13, Abenthung909 does not disclose wherein the metal alloy has a neutron absorption cross-section of no greater than 18 barn.
However, the composition of the alloy is the same as the claimed invention, and it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 comprises the claimed neutron absorption cross-section of no greater than 18 barn. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 18, Abenthung909 discloses wherein the metal alloy is a bulk metal alloy (Abstract; tubular target reads on bulk metal alloy).
Regarding Claim 19, Abenthung909 does not expressly disclose wherein the metal alloy is substantially stable at a temperature of at least 2500 °C.
However, the composition of the alloy is the same as the claimed invention, and it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 be substantially stable at a temperature of at least 2500 °C. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 21, Abenthung909 is silent towards the metal alloy rich in Cr at the grain boundaries of the metal alloy.
However, the composition of Abenthung909 (para. [0041], Mo alloy comprising up to 30wt% Cr; Mo-25wt%Cr alloy is equivalent to Mo-15at%Cr alloy), the particle size of Abenthung909 (para. [0013]. 0.5-10um), grain size taught by Wu (Fig. 8 and Fig. 9, 30nm or less), compaction process of Abenthung909 (para. [0014], 100-500MPa CIP green compact), and sintering process taught by Abenthung850 and Li2020 (Abenthung850, para. [0036], pressureless sintering using a 0.6-0.9 homologous temperature, approximately 1480C or more for Mo-15at% Cr; Li2020, Table 1, using temperature even lower than normal sintering by using a two-step process for 11 hours), is the same as the instant and claimed invention (see Fig. 9; Mo-15at%Cr; claimed 1um-1mm particle size and Pg. 4, Para. 4, particle sizes of less than 10um; claimed grain size of 100nm or less; Pg. 15-16, 300MPa or more for CIP green compact; claimed sintering temperatures of 1600C or less).
Therefore, it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 behave the same during sintering and resulted in metal alloy which is rich in Cr at the grain. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 44, Abenthung909 discloses wherein the second element present in the metal alloy is in an amount from 0.5-30wt%, which overlaps the claimed range of 0.5-40at% (para. [0041]; a Mo alloy comprising 0.5-30wt% of Cr would comprise Cr in an amount of about 1-19at%).
Regarding Claim 62, Abenthung909 does not expressly disclose wherein at least 90vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, Abenthung909 discloses wherein the average particle size is up to 10um, and it would be obvious that at least 90vol% of particles fall within the desired range of Abenthung909 (up to 10um), and therefore within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Regarding Claim 74, Wu discloses mechanically working (high energy ball milling) the precursor material prior to sintering such that at least a portion of the nanocrystalline particles contain both the Mo and the alloying element (Cr – see Abenthung909 disclosure) to sintering (Wu, Abstract, complete solid solution of Mo and alloying element; see also Abenthung909, para. [0041], wherein Mo is alloyed with Cr).
Regarding Claim 79, Li2020 discloses wherein the sintering time is less than or equal to 12 hours (see Table 1, two-step sintering process, total of 11 hours).
Regarding Claim 80 and Claim 81, Abenthung909 teaches using only metal particles and sintering in a vacuum (para. [0041]; para. [0021]), and one of ordinary skill in the art would appreciate that the metal alloy would therefore be comprised of metal atoms only in their metallic form (no other non-metal elements are included). Metal atoms only (100%) in metallic form reads on (Claim 80) 99at% and further (Claim 81) 99.9at% of the metal alloy made up of metal atoms in their metallic form, as claimed.
Claim 66 and Claim 67 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided), Abenthung850 (previously cited, US 20140238850 A1) and Li2020 (previously cited, “Pressureless two-step sintering of ultrafine-grained tungsten”), as applied to Claim 1 above, in further view of Park (previously cited, “Accelerated sintering in phase-separating nanostructured alloys” and Supplemental Data) and Sun (previously cited, “Thermodynamic Characteristic and Phase Evolution in Immiscible Cr–Mo Binary Alloys”).
Regarding Claims 66 and Claim 67, Abenthung909 teaches using sintering particles of Mo alloy comprising up to 30wt% of Cr, but is silent towards (Claim 66) Mo and Cr being present in a non-equilibrium phase in the particles, and further, (Claim 67) wherein the non-equilibrium phase is a supersaturated phase comprising Cr dissolved in the Mo.
Park teaches wherein high energy ball milling (mechanical alloying via mechanical working) achieves supersaturation even when elements do not show equilibrium solubility at room temperature (Pg. 2, Col. 2, Para. 1).
Wu discloses high energy ball milling to form a solid solution Mo and an alloy element with nanocrystalline grains (Abstract).
Sun teaches mechanical alloying by high energy ball milling to overcome thermodynamic barriers specifically for the immiscible Cr-Mo system and in order to form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys (Abstract; Section 3.1; Pg. 1076, Col. 2, Para. 2; Pg. 1080, Col. 1, Para. 1; see also Section 5, Conclusions, Para. 1). One of ordinary skill in the art would appreciate that a supersaturated solid solution phase of Cr-Mo, such as Cr-62Mo (see Pg. 1080, Col. 1, Para. 1), to comprise Mo and Cr present in a nonequilibrium phase, and further, one comprising Cr dissolved in the Mo.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the high energy ball milling of Wu, which forms nanocrystalline sintering powder and complete solid solution of Mo and the alloying element (Cr, see disclosure of Abenthung909), would comprise (Claim 66) a supersaturated solid solution (non-equilibrium phase), as taught by Park and Sun, and wherein (Claim 67) Cr is dissolved in the Mo for the supersaturated phase, as taught by Sun, for the invention disclosed by Abenthung909 and Wu, in order to overcome the thermodynamic barriers of the immiscible Cr-Mo system, and form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys.
Claims 2, 45, 53-54, 56-59, 65, 75 and 77-78 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided) and Abenthung850 (previously cited, US 20140238850 A1).
Regarding Claim 2, Abenthung909 discloses a method of forming a metal alloy (Abstract), comprising:
sintering particles comprising molybdenum (Mo) and chromium (Cr) to produce the metal alloy (para. [0019] and para. [0041], wherein metal powder is Mo alloy and comprises Cr; para. [0021], wherein powder is sintered), wherein:
Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of Cr would comprise Mo in an amount of 56-99at%);
the particles comprise an average size of 0.5-10um (para. [0019]); wherein
for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (para. [0021]; sintering in a vacuum would comprise an applied pressure of less than 2MPa; additionally, Abenthung909 does not disclose a pressure during sintering and therefore one of ordinary skill in the art would appreciate the sintering to occur without applied pressure); wherein
the sintering results in the metal alloy having a relative density in an amount of at least 98% (Abstract, 99%); and
wherein the metal alloy comprises an average grain size of less than 100um (Abstract; see also para. [0040], an average grain size of less than 100um reads on the claimed ‘grains having sizes greater than or equal to 1000 nm’).
Regarding the particle size of the sintering particles, Abenthung909 does not expressly disclose wherein at least 75vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, it would be obvious that an average particle size (at least 50%) of 0.5-10um overlap the claimed range of at least 75% of a total particle volume comprising maximum cross-sectional dimensions of about 1 micrometer to 1mm. Further it would be obvious to comprise 75vol% of the total particle volume within the desired range of Abenthung909 (up to 10um), and therefore at least 75% of the total particle volume within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Abenthung909 is silent towards the grain size of the sintering particles, and does not disclose wherein the particles comprise nanocrystalline particles are those with a grain size smaller than or equal to 100nm.
Wu teaches a spherical molybdenum alloy powder produced by high-energy ball-milling for molybdenum alloy target sintering, wherein the powder comprises a complete solid solution of molybdenum and the alloying element and a nanoscale internal crystallite size, thereby facilitating improved densification, reduced porosity and enhanced elemental and microstructural uniformity (Abstract; para. [0007]). Wu teaches an average grain size of 10um or less and an internal crystallite size of 30nm or less (Abstract; para. [0008], D50 of 2.58-2.634um and D10-D90 of 1.306-5.852um; para. [0041], crystal size of 13.56nm and particle size D50 of 2.63um; see also para. [0080], crystal sizes ranging from 13.68-23.23nm after ball-milling; see also Fig. 8 and Fig. 9, crystal grain sizes less than 30nm after ball milling).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a crystal grain size of 30nm or less, such as by high-energy ball milling, as taught by Wu, for the invention disclosed by Abenthung909, in order to comprise to facilitate improved densification, reduced porosity and enhanced elemental and microstructural uniformity through the complete solid solution of molybdenum and the alloying element (see teachings above).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP § 2144.05.I.
Regarding the density resulting from sintering, Abenthung909 teaches a density directly after sintering a green compact of greater than 95% (para. [0025]), and a density which occurs in the final product (and therefore as a result of sintering because the final product has been sintered) of 99% or more (Abstract).
Further, Abenthung850 teaches a Mo-Cr sintering particle, wherein a particle may have a size of 1.5-3um, wherein sintering obtains a sintered density of up to 99.5%, and wherein a pressureless sintering temperature is based on a homologous temperature of 0.6-0.9 (para. [0014]; para. [0027]; para. [0038]; para. [0036]). One of ordinary skill in the art would appreciate that the melting point for a 56at% Mo and 44at% Cr (Mo-30wt%Cr) is about 2175C, and therefore the 0.6-0.9 homologous temperature range would be 1305-1957C (see para. [0041] of Abenthung909 wherein Cr may be included up to 30wt%; 2175C melting point obtained from Cr-Mo phase diagram). One of ordinary skill in the art would appreciate that the lower temperature disclosed by Abenthung909 (1600C), appears to be approximately the 0.6 homologous temperature for pure Molybdenum.
Abenthung850 teaches wherein a sintered density of up to 99.5% reduces defects in subsequent deformation processes while balancing for coarse grain formation (para. [0038]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have alternatively used a 0.6-0.9 homologous temperature as the pressureless sintering temperature for the Mo-Cr alloy of Abenthung909, as taught by Abenthung850, including a pressureless sintering temperature as low as 1305C for the Mo-30wt% Cr alloy of Abenthung909 (see analysis above), and therefore comprised sintered density up to 99.5%, which reads on the claimed 98% or more, as taught by Abenthung850, for the invention disclosed by Abenthung909. One would be motivated to do this because the homologous temperature is based on the absolute melting point of the material and therefore this sintering temperature is more tailored to the alloy composition (see para. [0029] of Abenthung850), and in order to lower the sintering temperature while achieving up to 99.5% theoretical density, thereby reducing grain coarsening while maximizing for the reduction of defects in any subsequent deformation processes (see teachings above by Abenthung850).
Regarding Claim 53, Abenthung909 discloses a method of forming a metal alloy (Abstract), comprising:
sintering particles comprising molybdenum (Mo) and chromium (Cr) to produce the metal alloy (para. [0019] and para. [0041], wherein metal powder is Mo alloy and comprises Cr; para. [0021], wherein powder is sintered), wherein:
Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of Cr would comprise Mo in an amount of 56-99at%);
the particles comprise an average size of 0.5-10um (para. [0019]); wherein
for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (para. [0021]; sintering in a vacuum would comprise an applied pressure of less than 2MPa; additionally, Abenthung909 does not disclose a pressure during sintering and therefore one of ordinary skill in the art would appreciate the sintering to occur without applied pressure); wherein
the sintering results in the metal alloy having a relative density in an amount of at least 98% (Abstract, 99%); and
wherein the metal alloy comprises an average grain size of less than 100um (Abstract; see also para. [0040], an average grain size of less than 100um reads on the claimed ‘grains having sizes greater than or equal to 1000 nm’).
Abenthung909 is silent towards the grain size of the sintering particles, and does not disclose wherein the particles comprise nanocrystalline particles are those with a grain size smaller than or equal to 100nm.
Wu teaches a spherical molybdenum alloy powder produced by high-energy ball-milling for molybdenum alloy target sintering, wherein the powder comprises a complete solid solution of molybdenum and the alloying element and a nanoscale internal crystallite size, thereby facilitating improved densification, reduced porosity and enhanced elemental and microstructural uniformity (Abstract; para. [0007]). Wu teaches an average grain size of 10um or less and an internal crystallite size of 30nm or less (Abstract; para. [0008], D50 of 2.58-2.634um and D10-D90 of 1.306-5.852um; para. [0041], crystal size of 13.56nm and particle size D50 of 2.63um; see also para. [0080], crystal sizes ranging from 13.68-23.23nm after ball-milling; see also Fig. 8 and Fig. 9, crystal grain sizes less than 30nm after ball milling).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a crystal grain size of 30nm or less, such as by high-energy ball milling, as taught by Wu, for the invention disclosed by Abenthung909, in order to comprise to facilitate improved densification, reduced porosity and enhanced elemental and microstructural uniformity through the complete solid solution of molybdenum and the alloying element (see teachings above).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP § 2144.05.I.
Regarding the density resulting from sintering, Abenthung909 teaches a density directly after sintering a green compact of greater than 95% (para. [0025]), and a density which occurs in the final product (and therefore as a result of sintering because the final product has been sintered) of 99% or more (Abstract).
Further, Abenthung850 teaches a Mo-Cr sintering particle, wherein a particle may have a size of 1.5-3um, wherein sintering obtains a sintered density of up to 99.5%, and wherein a pressureless sintering temperature is based on a homologous temperature of 0.6-0.9 (para. [0014]; para. [0027]; para. [0038]; para. [0036]). One of ordinary skill in the art would appreciate that the melting point for a 56at% Mo and 44at% Cr (Mo-30wt%Cr) is about 2175C, and therefore the 0.6-0.9 homologous temperature range would be 1305-1957C (see para. [0041] of Abenthung909 wherein Cr may be included up to 30wt%; 2175C melting point obtained from Cr-Mo phase diagram). One of ordinary skill in the art would appreciate that the lower temperature disclosed by Abenthung909 (1600C), appears to be approximately the 0.6 homologous temperature for pure Molybdenum.
Abenthung850 teaches wherein a sintered density of up to 99.5% reduces defects in subsequent deformation processes while balancing for coarse grain formation (para. [0038]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have alternatively used a 0.6-0.9 homologous temperature as the pressureless sintering temperature for the Mo-Cr alloy of Abenthung909, as taught by Abenthung850, including a pressureless sintering temperature as low as 1305C for the Mo-30wt% Cr alloy of Abenthung909 (see analysis above), and therefore comprised sintered density up to 99.5%, which reads on the claimed 98% or more, as taught by Abenthung850, for the invention disclosed by Abenthung909. One would be motivated to do this because the homologous temperature is based on the absolute melting point of the material and therefore this sintering temperature is more tailored to the alloy composition (see para. [0029] of Abenthung850), and in order to lower the sintering temperature while achieving up to 99.5% theoretical density, thereby reducing grain coarsening while maximizing for the reduction of defects in any subsequent deformation processes (see teachings above by Abenthung850).
Abenthung909 is silent towards a non-equilibrium phase undergoing decomposition during the sintering of the (nanocrystalline) particles.
However, the composition of Abenthung909 (Mo alloy comprising up to 30wt% Cr – see para. [0041]; Mo-25wt%Cr alloy is equivalent to Mo-15at%Cr alloy), is the same as the instant invent (see Fig. 9; Mo-15at%Cr), and further, the grain size (30nm or less – see teaching by Wu) and particle sizes and sintering process/temperatures of Abenthung909 (see para. [0019]-[0021], 0.5-10um particles, 100-500MPa CIP green compact; sintering temperatures of 1600-2500C) are the same as the instant invention (claimed grain size of 100nm or less; see Pg. 4, Para. 4, particle sizes of less than 10um; see Pg. 15-16, 300MPa or more for CIP green compact; sintering temperatures of 2200C or less and 1600C or more).
Therefore, it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 comprises the claimed decomposition of a non-equilibrium phase during sintering of the particles. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 59, Abenthung909 discloses a method of forming a metal alloy (Abstract), comprising:
sintering particles comprising molybdenum (Mo) and chromium (Cr) to produce the metal alloy (para. [0019] and para. [0041], wherein metal powder is Mo alloy and comprises Cr; para. [0021], wherein powder is sintered), wherein:
Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of Cr would comprise Mo in an amount of 56-99at%);
the particles comprise an average size of 0.5-10um (para. [0019]); wherein
for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (para. [0021]; sintering in a vacuum would comprise an applied pressure of less than 2MPa; additionally, Abenthung909 does not disclose a pressure during sintering and therefore one of ordinary skill in the art would appreciate the sintering to occur without applied pressure); wherein
the sintering results in the metal alloy having a relative density in an amount of at least 98% (Abstract, 99%); and
wherein the metal alloy comprises an average grain size of less than 100um (Abstract; see also para. [0040], an average grain size of less than 100um reads on the claimed ‘grains having sizes greater than or equal to 1000 nm’).
Abenthung909 is silent towards the grain size of the sintering particles, and does not disclose wherein the particles comprise nanocrystalline particles are those with a grain size smaller than or equal to 100nm.
Wu teaches a spherical molybdenum alloy powder produced by high-energy ball-milling for molybdenum alloy target sintering, wherein the powder comprises a complete solid solution of molybdenum and the alloying element and a nanoscale internal crystallite size, thereby facilitating improved densification, reduced porosity and enhanced elemental and microstructural uniformity (Abstract; para. [0007]). Wu teaches an average grain size of 10um or less and an internal crystallite size of 30nm or less (Abstract; para. [0008], D50 of 2.58-2.634um and D10-D90 of 1.306-5.852um; para. [0041], crystal size of 13.56nm and particle size D50 of 2.63um; see also para. [0080], crystal sizes ranging from 13.68-23.23nm after ball-milling; see also Fig. 8 and Fig. 9, crystal grain sizes less than 30nm after ball milling).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a crystal grain size of 30nm or less, such as by high-energy ball milling, as taught by Wu, for the invention disclosed by Abenthung909, in order to comprise to facilitate improved densification, reduced porosity and enhanced elemental and microstructural uniformity through the complete solid solution of molybdenum and the alloying element (see teachings above).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP § 2144.05.I.
Regarding the density resulting from sintering, Abenthung909 teaches a density directly after sintering a green compact of greater than 95% (para. [0025]), and a density which occurs in the final product (and therefore as a result of sintering because the final product has been sintered) of 99% or more (Abstract).
Further, Abenthung850 teaches a Mo-Cr sintering particle, wherein a particle may have a size of 1.5-3um, wherein sintering obtains a sintered density of up to 99.5%, and wherein a pressureless sintering temperature is based on a homologous temperature of 0.6-0.9 (para. [0014]; para. [0027]; para. [0038]; para. [0036]). One of ordinary skill in the art would appreciate that the melting point for a 56at% Mo and 44at% Cr (Mo-30wt%Cr) is about 2175C, and therefore the 0.6-0.9 homologous temperature range would be 1305-1957C (see para. [0041] of Abenthung909 wherein Cr may be included up to 30wt%; 2175C melting point obtained from Cr-Mo phase diagram). One of ordinary skill in the art would appreciate that the lower temperature disclosed by Abenthung909 (1600C), appears to be approximately the 0.6 homologous temperature for pure Molybdenum.
Abenthung850 teaches wherein a sintered density of up to 99.5% reduces defects in subsequent deformation processes while balancing for coarse grain formation (para. [0038]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have alternatively used a 0.6-0.9 homologous temperature as the pressureless sintering temperature for the Mo-Cr alloy of Abenthung909, as taught by Abenthung850, including a pressureless sintering temperature as low as 1305C for the Mo-30wt% Cr alloy of Abenthung909 (see analysis above), and therefore comprised sintered density up to 99.5%, which reads on the claimed 98% or more, as taught by Abenthung850, for the invention disclosed by Abenthung909. One would be motivated to do this because the homologous temperature is based on the absolute melting point of the material and therefore this sintering temperature is more tailored to the alloy composition (see para. [0029] of Abenthung850), and in order to lower the sintering temperature while achieving up to 99.5% theoretical density, thereby reducing grain coarsening while maximizing for the reduction of defects in any subsequent deformation processes (see teachings above by Abenthung850).
Abenthung909 is silent towards forming necks with Cr between Mo particles and/or grains during sintering.
However, the composition of Abenthung909 (Mo alloy comprising up to 30wt% Cr – see para. [0041]; Mo-25wt%Cr alloy is equivalent to Mo-15at%Cr alloy), is the same as the instant invent (see Fig. 9; Mo-15at%Cr), and further, the grain size (30nm or less – see teaching by Wu) and particle sizes and sintering process/temperatures of Abenthung909 (see para. [0019]-[0021], 0.5-10um particles, 100-500MPa CIP green compact; sintering temperatures of 1600-2500C) are the same as the instant invention (claimed grain size of 100nm or less; see Pg. 4, Para. 4, particle sizes of less than 10um; see Pg. 15-16, 300MPa or more for CIP green compact; sintering temperatures of 2200C or less and 1600C or more).
Therefore, it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 behave the same during sintering and formed necks via Cr between Mo particles and/or grains as claimed. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 45 and Claim 58, Abenthung909 discloses wherein the Cr is present in the metal alloy is in an amount from 0.5-30wt%, which overlaps the claimed range of 0.5-40at% (para. [0041]; a Mo alloy comprising 0.5-30wt% of Cr would comprise Cr in an amount of about 1-19at%).
Regarding Claim 54, Abenthung909 does not disclose wherein the metal alloy has a neutron absorption cross-section of no greater than 18 barn.
However, the composition of the alloy is the same as the claimed invention, and it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 comprises the claimed neutron absorption cross-section of no greater than 18 barn. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 56, Abenthung909 discloses wherein the metal alloy is a bulk metal alloy (Abstract; tubular target reads on bulk metal alloy).
Regarding Claim 57, Abenthung909 discloses wherein Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of a second element would comprise Mo in an amount of at least 55at%; for example, a Mo alloy comprising 0.5-30wt% of Cr would comprise Mo in an amount of about 81-99at%).
Regarding Claim 65, Abenthung909 does not expressly disclose wherein at least 90vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, Abenthung909 discloses wherein the average particle size is up to 10um, and it would be obvious that at least 90vol% of particles fall within the desired range of Abenthung909 (up to 10um), and therefore within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Regarding Claim 75, Claim 77 and Claim 78, Wu discloses mechanically working (high energy ball milling) the precursor material prior to sintering such that at least a portion of the nanocrystalline particles contain both the Mo and the alloying element (Cr – see Abenthung909 disclosure) to sintering (Wu, Abstract, complete solid solution of Mo and alloying element; see also Abenthung909, para. [0041], wherein Mo is alloyed with Cr).
Claim 68 and Claim 69 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided) and Abenthung850 (previously cited, US 20140238850 A1), as applied to Claim 2 above, in further view of Park (previously cited, “Accelerated sintering in phase-separating nanostructured alloys” and Supplemental Data) and Sun (previously cited, “Thermodynamic Characteristic and Phase Evolution in Immiscible Cr–Mo Binary Alloys”).
Regarding Claims 68 and Claim 69, Abenthung909 teaches using sintering particles of Mo alloy comprising up to 30wt% of Cr, but is silent towards (Claim 68) Mo and Cr being present in a non-equilibrium phase in the particles, and further, (Claim 69) wherein the non-equilibrium phase is a supersaturated phase comprising Cr dissolved in the Mo.
Park teaches wherein high energy ball milling (mechanical alloying via mechanical working) achieves supersaturation even when elements do not show equilibrium solubility at room temperature (Pg. 2, Col. 2, Para. 1).
Wu discloses high energy ball milling to form a solid solution Mo and an alloy element with nanocrystalline grains (Abstract).
Sun teaches mechanical alloying by high energy ball milling to overcome thermodynamic barriers specifically for the immiscible Cr-Mo system and in order to form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys (Abstract; Section 3.1; Pg. 1076, Col. 2, Para. 2; Pg. 1080, Col. 1, Para. 1; see also Section 5, Conclusions, Para. 1). One of ordinary skill in the art would appreciate that a supersaturated solid solution phase of Cr-Mo, such as Cr-62Mo (see Pg. 1080, Col. 1, Para. 1), to comprise Mo and Cr present in a nonequilibrium phase, and further, one comprising Cr dissolved in the Mo.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the high energy ball milling of Wu, which forms nanocrystalline sintering powder and complete solid solution of Mo and the alloying element (Cr, see disclosure of Abenthung909), would comprise (Claim 68) a supersaturated solid solution (non-equilibrium phase), as taught by Park and Sun, and wherein (Claim 69) Cr is dissolved in the Mo for the supersaturated phase, as taught by Sun, for the invention disclosed by Abenthung909 and Wu, in order to overcome the thermodynamic barriers of the immiscible Cr-Mo system, and form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys.
Claim 72 and Claim 73 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided) and Abenthung850 (previously cited, US 20140238850 A1), as applied to Claim 53 above, in further view of Park (previously cited, “Accelerated sintering in phase-separating nanostructured alloys” and Supplemental Data) and Sun (previously cited, “Thermodynamic Characteristic and Phase Evolution in Immiscible Cr–Mo Binary Alloys”).
Regarding Claims 72 and Claim 73, Abenthung909 teaches using sintering particles of Mo alloy comprising up to 30wt% of Cr, but is silent towards (Claim 72) Mo and Cr being present in a non-equilibrium phase in the particles, and further, (Claim 73) wherein the non-equilibrium phase is a supersaturated phase comprising Cr dissolved in the Mo.
Park teaches wherein high energy ball milling (mechanical alloying via mechanical working) achieves supersaturation even when elements do not show equilibrium solubility at room temperature (Pg. 2, Col. 2, Para. 1).
Wu discloses high energy ball milling to form a solid solution Mo and an alloy element with nanocrystalline grains (Abstract).
Sun teaches mechanical alloying by high energy ball milling to overcome thermodynamic barriers specifically for the immiscible Cr-Mo system and in order to form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys (Abstract; Section 3.1; Pg. 1076, Col. 2, Para. 2; Pg. 1080, Col. 1, Para. 1; see also Section 5, Conclusions, Para. 1). One of ordinary skill in the art would appreciate that a supersaturated solid solution phase of Cr-Mo, such as Cr-62Mo (see Pg. 1080, Col. 1, Para. 1), to comprise Mo and Cr present in a nonequilibrium phase, and further, one comprising Cr dissolved in the Mo.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the that the high energy ball milling of Wu, which forms nanocrystalline sintering powder and complete solid solution of Mo and the alloying element (Cr, see disclosure of Abenthung909), would comprise (Claim 72) a supersaturated solid solution (non-equilibrium phase), as taught by Park and Sun, and wherein (Claim 73) Cr is dissolved in the Mo for the supersaturated phase, as taught by Sun, for the invention disclosed by Abenthung909 and Wu, in order to overcome the thermodynamic barriers of the immiscible Cr-Mo system, and form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys.
Claims 1, 7-13, 18-19, 21, 44, 62, 74 and 79-81 are alternatively rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided), Spielmann (previously cited, US 20070148031 A1) and Li2020 (previously cited, “Pressureless two-step sintering of ultrafine-grained tungsten”).
Regarding Claim 1, Abenthung909 discloses a method of forming a metal alloy (Abstract), comprising:
sintering particles comprising molybdenum (Mo) and chromium (Cr) to produce the metal alloy (para. [0019] and para. [0041], wherein metal powder is Mo alloy and comprises Cr; para. [0021], wherein powder is sintered), wherein:
Mo is present in the metal alloy in an amount of at least 55at% (para. [0041]; a Mo alloy comprising 0.5-30% of Cr would comprise Mo in an amount of 56-99at%);
the particles comprise an average size of 0.5-10um (para. [0019]); wherein
for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (para. [0021]; sintering in a vacuum would comprise an applied pressure of less than 2MPa; additionally, Abenthung909 does not disclose a pressure during sintering and therefore one of ordinary skill in the art would appreciate the sintering to occur without applied pressure); wherein
the sintering results in the metal alloy having a relative density in an amount of at least 98% (Abstract, 99%); and
wherein the metal alloy comprises an average grain size of less than 100um (Abstract; see also para. [0040], an average grain size of less than 100um reads on the claimed ‘grains having sizes greater than or equal to 1000 nm’).
Regarding the particle size of the sintering particles, Abenthung909 does not expressly disclose wherein at least 75vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, it would be obvious that an average particle size (at least 50%) of 0.5-10um overlap the claimed range of at least 75% of a total particle volume comprising maximum cross-sectional dimensions of about 1 micrometer to 1mm. Further it would be obvious to comprise 75vol% of the total particle volume within the desired range of Abenthung909 (up to 10um), and therefore at least 75% of the total particle volume within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Abenthung909 is silent towards the grain size of the sintering particles, and does not disclose wherein the particles comprise nanocrystalline particles are those with a grain size smaller than or equal to 100nm.
Wu teaches a spherical molybdenum alloy powder produced by high-energy ball-milling for molybdenum alloy target sintering, wherein the powder comprises a complete solid solution of molybdenum and the alloying element and a nanoscale internal crystallite size, thereby facilitating improved densification, reduced porosity and enhanced elemental and microstructural uniformity (Abstract; para. [0007]). Wu teaches an average grain size of 10um or less and an internal crystallite size of 30nm or less (Abstract; para. [0008], D50 of 2.58-2.634um and D10-D90 of 1.306-5.852um; para. [0041], crystal size of 13.56nm and particle size D50 of 2.63um; see also para. [0080], crystal sizes ranging from 13.68-23.23nm after ball-milling; see also Fig. 8 and Fig. 9, crystal grain sizes less than 30nm after ball milling).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a crystal grain size of 30nm or less, such as by high-energy ball milling, as taught by Wu, for the invention disclosed by Abenthung909, in order to comprise to facilitate improved densification, reduced porosity and enhanced elemental and microstructural uniformity through the complete solid solution of molybdenum and the alloying element (see teachings above).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP § 2144.05.I.
Abenthung909 discloses wherein sintering temperature may be as low as 1600C, but does not disclose wherein 1600C achieves a density of greater than 98% for a sintering particles size of 1um-1mm as claimed.
Further, Abenthung909 is silent towards sintering time.
Spielmann teaches modifying sintering temperature of molybdenum and molybdenum alloy powders to be 0.55-0.92 times the solidus temperature, such that powers the size of 0.5-10um, pressed into compacts using a pressure of 100-500MPa (the same as disclosed and desired by Abenthung909 – see para. [0025] of Abenthung909 wherein powders range from 0.5-10um and are pressed using pressures of 100-500MPa), achieve a sintered relative density up to 98.5%, thereby obtaining a fine grained microstructure while balancing for porosity (Abstract; para. [0017]-[0019]). One of ordinary skill in the art would appreciate that Spielmann teaches wherein the sintering temperature for a Mo-30wt%Cr alloy would be as low as 0.55*2073C, or 1140 C (solidus based on Mo-Cr phase diagram)).
Further, Li2020 teaches wherein a pressureless, reduced temperature, two-step sintering process of 11 hours achieves 99% theoretical density, mitigates grain coarsening, and significantly lowers required sintering temperatures as compared to normal sintering (Table 1, wherein 99.6% density is achieved at 1600C for 3 hours for normal sintering, and 99.1% density is achieved at 1450C (1hr) and 1350C (10hrs) for two-step sintering – 11 hours total). While Li2020 is directed to tungsten, one of ordinary skill in the art would appreciate the applicability of Li2020 to Mo materials and those Abenthung909 because Abenthung909 teaches pressureless sintering for Mo materials which may comprise W (see para. [0041] of Abenthung909; additionally, Spielmann does not disclose pressured sintering, and one of ordinary skill in the art would appreciate this to be pressureless sintering), both W and Mo are refractory metals and 6b metals which alloy with each other, and Li2020 does not appear to suggest that the two-step process is limited to W or pure W.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have alternatively used a sintering temperature of 0.55-0.92*solidus temperature for the Mo-Cr alloy of Abenthung909, as taught by Spielmann, including a sintering temperature as low as 1140C for the Mo-30wt% Cr alloy of Abenthung909 (see analysis above), and further an 11 hour two-step pressureless sintering process such that the sintering temperature is further reduced (less than 1600C), as taught by Li2020. One would be motivated to do this because the solidus temperature is tailored for the specific alloy composition, and in order to lower the sintering temperature while achieving 99% theoretical density and mitigating significant or unwanted grain coarsening (see teachings above by Li2020).
Therefore, Abenthung909, Spielmann and Li2020 disclose wherein the sintering temperature is 1600C or less for 99% of sintering time, wherein sintering is less than 24hours (11 hours), and a density of 98% or greater is formed from the particle sizes disclosed by Abenthung909 and at the temperatures taught by Spielmann (and Li2020).
Additionally, the particle composition (Mo-Cr, disclosed by Abenthung909), particle size (1-10um, disclosed by Abenthung909), and grain size (30nm or less, taught by Wu), are the same as claimed (Mo-Cr with at least 55at% Mo, 1um-1mm particle size, and grain size of 100nm or less), and it would be expected that the particles achieve the same densification of 98% or greater for the same pressureless sintering temperatures and times (1600C or less, see teachings by Spielmann and Li2020; less than 24 hours, see teaching by Li2020).
When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 7, Abenthung909 discloses further comprising a third element (para. [0041], wherein multiple additional alloying elements may be included).
Regarding Claim 8, Abenthung909 discloses wherein the third element present in the metal alloy is in an amount from 0.5-30wt%, which overlaps the claimed range of 0.5-40at% (para. [0041], wherein 0.5-30wt% of Cr, W, or Ta may be included). For example, a Mo alloy comprising 25%Cr and 5wt% W would comprise 38.8at% Cr, 2.2at% W and 59at% Mo, and a Mo alloy comprising 25wt%Cr, 3wt%W and 2wt% Ta would comprise 38.8at% Cr, 1.3at% W, 0.9at%Ta and 59at% Mo.
Regarding Claim 9, Abenthung909 discloses wherein the second element may be Cr and the third element may be W, and therefore discloses elements which exhibit the claimed miscibility gap (para. [0041], wherein Mo is alloyed with Cr (second element) and may also be alloyed with W (third element)). One of ordinary skill in the art would appreciate that Cr and W exhibit a miscibility gap, as seen on the binary phase diagram of W and Cr).
Regarding Claim 10, Abenthung909 discloses wherein the third element is tungsten (see para. [0041], wherein 0.5-30wt% of Cr (second element) and additionally Ta and/or W (third element) may be included).
Regarding Claim 11, Abenthung909 discloses wherein the third element is tantalum (see para. [041], wherein 0.5-30wt% of Cr (second element) and additionally Ta and/or W (third element) may be included).
Regarding Claim 12, Abenthung909 discloses wherein the Mo alloy may comprise up to 30wt% Cr (para. [0041]), and one of ordinary skill in the art would appreciate that a Mo alloy comprising 12.5at% or less Cr (7.2wt% or less) would have a melting point of 2500C or greater (based on the binary diagram of Mo an Cr), as claimed.
Regarding Claim 13, Abenthung909 does not disclose wherein the metal alloy has a neutron absorption cross-section of no greater than 18 barn.
However, the composition of the alloy is the same as the claimed invention, and it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 comprises the claimed neutron absorption cross-section of no greater than 18 barn. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 18, Abenthung909 discloses wherein the metal alloy is a bulk metal alloy (Abstract; tubular target reads on bulk metal alloy).
Regarding Claim 19, Abenthung909 does not expressly disclose wherein the metal alloy is substantially stable at a temperature of at least 2500 °C.
However, the composition of the alloy is the same as the claimed invention, and it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 be substantially stable at a temperature of at least 2500 °C. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 21, Abenthung909 is silent towards the metal alloy rich in Cr at the grain boundaries of the metal alloy.
However, the composition of Abenthung909 (para. [0041], Mo alloy comprising up to 30wt% Cr; Mo-25wt%Cr alloy is equivalent to Mo-15at%Cr alloy), the particle size of Abenthung909 (para. [0013]. 0.5-10um), grain size taught by Wu (Fig. 8 and Fig. 9, 30nm or less), compaction process of Abenthung909 (para. [0014], 100-500MPa CIP green compact), and sintering process taught by Spielmann and Li2020 (Spielmann, para. [0026], pressureless sintering using a 0.55-0.92* solidus temperature, approximately 1320C or more for Mo-15at% Cr; Li2020, Table 1, using temperature even lower than normal sintering by using a two-step process for 11 hours), is the same as the instant and claimed invention (see Fig. 9; Mo-15at%Cr; claimed 1um-1mm particle size and Pg. 4, Para. 4, particle sizes of less than 10um; claimed grain size of 100nm or less; Pg. 15-16, 300MPa or more for CIP green compact; claimed sintering temperatures of 1600C or less).
Therefore, it would be obvious to one of ordinary skill in the art that the alloy of Abenthung909 behave the same during sintering and resulted in metal alloy which is rich in Cr at the grain. When the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01.
Regarding Claim 44, Abenthung909 discloses wherein the second element present in the metal alloy is in an amount from 0.5-30wt%, which overlaps the claimed range of 0.5-40at% (para. [0041]; a Mo alloy comprising 0.5-30wt% of Cr would comprise Cr in an amount of about 1-19at%).
Regarding Claim 62, Abenthung909 does not expressly disclose wherein at least 90vol% of the total particle volume is made up of particles having maximum cross-sectional dimensions from about 1um to 1mm. However, Abenthung909 discloses wherein the average particle size is up to 10um, and it would be obvious that at least 90vol% of particles fall within the desired range of Abenthung909 (up to 10um), and therefore within the claimed range of 1um-1mm, in order to manufacture the molybdenum alloy with as close to the desired particle size as possible and also in order to have a consistent, resultant microstructure after processing.
Regarding Claim 74, Wu discloses mechanically working (high energy ball milling) the precursor material prior to sintering such that at least a portion of the nanocrystalline particles contain both the Mo and the alloying element (Cr – see Abenthung909 disclosure) to sintering (Wu, Abstract, complete solid solution of Mo and alloying element; see also Abenthung909, para. [0041], wherein Mo is alloyed with Cr).
Regarding Claim 79, Li2020 discloses wherein the sintering time is less than or equal to 12 hours (see Table 1, two-step sintering process, total of 11 hours).
Regarding Claim 80 and Claim 81, Abenthung909 teaches using only metal particles and sintering in a vacuum (para. [0041]; para. [0021]), and one of ordinary skill in the art would appreciate that the metal alloy would therefore be comprised of metal atoms only in their metallic form (no other non-metal elements are included). Metal atoms only (100%) in metallic form reads on (Claim 80) 99at% and further (Claim 81) 99.9at% of the metal alloy made up of metal atoms in their metallic form, as claimed.
Claim 66 and Claim 67 are rejected under 35 U.S.C. 103 as being unpatentable over Abenthung909 (previously cited and cited by Applicant in IDS filed March 28, 2024, US 20070086909 A1) in view of Wu (CN 110976888 A, English Machine Translation provided), Spielmann (previously cited, US 20070148031 A1) and Li2020 (previously cited, “Pressureless two-step sintering of ultrafine-grained tungsten”), as applied to Claim 1 above, in further view of Park (previously cited, “Accelerated sintering in phase-separating nanostructured alloys” and Supplemental Data) and Sun (previously cited, “Thermodynamic Characteristic and Phase Evolution in Immiscible Cr–Mo Binary Alloys”).
Regarding Claims 66 and Claim 67, Abenthung909 teaches using sintering particles of Mo alloy comprising up to 30wt% of Cr, but is silent towards (Claim 66) Mo and Cr being present in a non-equilibrium phase in the particles, and further, (Claim 67) wherein the non-equilibrium phase is a supersaturated phase comprising Cr dissolved in the Mo.
Park teaches wherein high energy ball milling (mechanical alloying via mechanical working) achieves supersaturation even when elements do not show equilibrium solubility at room temperature (Pg. 2, Col. 2, Para. 1).
Wu discloses high energy ball milling to form a solid solution Mo and an alloy element with nanocrystalline grains (Abstract).
Sun teaches mechanical alloying by high energy ball milling to overcome thermodynamic barriers specifically for the immiscible Cr-Mo system and in order to form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys (Abstract; Section 3.1; Pg. 1076, Col. 2, Para. 2; Pg. 1080, Col. 1, Para. 1; see also Section 5, Conclusions, Para. 1). One of ordinary skill in the art would appreciate that a supersaturated solid solution phase of Cr-Mo, such as Cr-62Mo (see Pg. 1080, Col. 1, Para. 1), to comprise Mo and Cr present in a nonequilibrium phase, and further, one comprising Cr dissolved in the Mo.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the high energy ball milling of Wu, which forms nanocrystalline sintering powder and complete solid solution of Mo and the alloying element (Cr, see disclosure of Abenthung909), would comprise (Claim 66) a supersaturated solid solution (non-equilibrium phase), as taught by Park and Sun, and wherein (Claim 67) Cr is dissolved in the Mo for the supersaturated phase, as taught by Sun, for the invention disclosed by Abenthung909 and Wu, in order to overcome the thermodynamic barriers of the immiscible Cr-Mo system, and form a supersaturated solid solution Mo-Cr phase for different Cr-Mo binary alloys.
Response to Arguments
Applicant’s arguments, filed October 20, 2025, with respect to Claims 1-2, 46, 53 and 59, and dependent claims thereof, rejected under 35 U.S.C. 103 over 35 U.S.C. 103 over Abenthung909, Petkovic-Luton, Abenthung850 and Li2020 (Claim 1 and dependent claims thereof), over Abenthung909 an Petkovic-Luton (Claims 2, 53 and 59, and dependent claims thereof) and further and alternatively over Abenthung909, Petkovic-Luton, Spielmann and Li2020 (Claim 1 and dependent claims thereof), have been fully considered. Upon further consideration, a new rejection is made under 35 U.S.C. 103 over Abenthung909, Wu, Abenthung850 and Li2020 (Claim 1 and dependent claims thereof), over Abenthung909 and Wu (Claims 2, 53 and 59, and dependent claims thereof) and further and alternatively over Abenthung909, Wu, Spielmann and Li2020 (Claim 1 and dependent claims thereof).
Applicant' s arguments directed to the Petkovic-Luton are deemed moot in view of the new grounds of rejection.
Regarding Abenthung909 and Abenthung850:
Applicant argues that Abenthung909 does not disclose a theoretical density of 98% or greater resulting from sintering and the relative densities disclosed are not sintered relative densities.
Applicant argues that Abenthung850 provides no working example of obtaining the disclosed sintered density up to 99.5%, or one of at least the claimed 98%.
Applicant argues that not all refractory metals can be sintered to 98% or more.
These arguments are not found persuasive.
Abenthung909 discloses Mo-Cr green compacts sintered to a density of greater than 95% theoretical density (para. [0025]), and Abenthung850 further teaches Mo-Cr green compacts sintered to a density of 99.5% (para. [0038], average relative sintered density of 80-99.5%) in order to reduce coarse grain formation while balancing with reduction of defects in subsequent deformation processes. It would be obvious to sinter to the disclosed 99.5% density in order to maximize a sintered compact that does not form defects upon subsequent deformation processes (see teaching and rejections above).
Regarding “sintered relative densities”, this is not a currently claimed feature, and therefore not commensurate in scope with the claims. The claims currently recite wherein “the sintering results in the metal alloy having a relative density of at least 98%”, but does not recite wherein the relative density is that from the sintering alone. The relative density claimed does not currently prohibit further processes in addition to sintering. The density of Abenthung909 of greater than 99% (Abstract) which results from both sintering and further processes reads on the claimed limitation as written. However, Abenthung850 also teaches the referred to ‘sintered relative densities’ which results from the sintering (alone) of the green compact.
Regarding working examples and Abenthung850, a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art, including nonpreferred embodiments, and disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments (MPEP 2123.I&II). Abenthung850 does not require a working example to be relied upon for the teaching to be applicable, and the broader disclosure expressly recites a 99.5% sintered density, with both an expressed method (sintering temperature modification) and a motivation (reduction of defects) to achieve that density.
Regarding the alternative rejection in view of Abenthung909, Wu and Speilmann, the sintering particle (particle size, composition and crystalline grain size), the sintering temperatures and sintering times of Abenthung909, Wu and Speilmann are the same as claimed and it would be obvious that the sintering result in the claimed density and further a density of 98% or more from sintering alone.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Lee (previously cited and cited by Applicant in IDS filed September 10, 2021, “Oxidation of Molybdenum-Chromium-Palladium Alloys”): discloses a method of forming a metal alloy (Abstract), comprising sintering particles comprising molybdenum (Mo) and a second element to produce the metal alloy (see Pg. 14, Experimental; see Table II compositions where either Cr or Pd may be considered the second element), wherein Mo is present in the metal alloy in an amount of at least 55at% (see Table II compositions); and for at least 20% of the time during which the sintering is performed, the maximum external pressure applied to the particles is less than or equal to 2MPa (see Pg. 14, Experimental). Lee does not disclose wherein pressure is used during sintering, and one of ordinary skill in the art would appreciate that the sintering of Lee would be pressureless or natural sintering, and therefore be performed under an applied pressure of 0 MPa, which reads on the claimed limitations.
Lee further discloses using micron size (1um-1mm) elemental powder to form the sintering powder (Table 1), and densities as high as 93% (+/-2%) (see Table II densities). Lee teaches that the Mo-Cr-Pd is a similar system to the W-Cr-Pd system (Introduction).
Rao (previously cited, “The Mo-W (Molybdenum-Tungsten) System”): teaches that Mo is well-known as a substitute for W in alloying due to the similar crystal structures and lattice parameters, as well as the ability to form a continuous bcc structured solid solution (Rao; Table 1; Pg. 178, Col. 2, Para. 1-3).
Additional teachings by Park (previously cited and cited above, “Accelerated sintering in phase-separating nanostructured alloys” and Supplemental Data): teaches enhanced and accelerated sintering and densification for the similar W-Cr system, and specifically an alloy comprising 15at%Cr (Lee also discloses Mo compositions with 15at%Cr), which produces nanocrystalline bulk microstructures and reaches densities of greater than 98% without externally applied pressure during sintering (Abstract; Pg. 2, Col. 2, Para. 2).
Park teaches wherein this is achieved by sintering with microscale (1um-1mm) powder comprising nanocrystalline grain sizes within the particle, wherein the particle is in a supersaturated state of solid solution despite miscibility gaps, and wherein phase separation occurs at higher temperatures (Pg. 2, Col. 2, Para. 1; Pg. 2, Col. 2, Para. 3; see Fig. 1(a) wherein powder is micron sized; see Supplementary Fig. 1 wherein all particles are about 1um and Supplementary Table 1).
Lee1991 (previously cited and cited by Applicant in IDS filed September 10, 2021, “Oxidation resistant Mo-W-Cr-Pd alloys with palladium coatings”): discloses a similar alloy to Lee (see cited reference above) comprising W, which substitutes for Mo, such that the combination of W and Mo is more oxidation resistant and comprises improved oxidation life than a W-Cr-Pd alloy (Lee1991, Introduction, wherein Mo-W-Cr-Pd shows increased oxidation resistance compared with W-Cr-Pd).
Additionally, the combination of W and Mo is also more oxidation resistant than the Mo-Cr-Pd (see Fig. 2 of Lee, wherein the composition of 90Mo-8Cr-1Pd shows a weight loss of more than 8 mg/cm2 for cyclic oxidation at 1000C; see Fig. 3 of Lee1991, wherein the composition of 45Mo-45W-9Cr-1Pd and 50Mo-40W-9Cr-1Pd shows improved oxidation with a weight loss of about 2 to 3 mg/cm2 for cyclic oxidation at 1000C).
Ham (previously cited, US 2678270 A): teaches additions of 0.5-9wt% Ta to a molybdenum alloy improve high temperature hardness and strength (Col. 3, lines 60-63; Col. 4, lines 6-9).
Li584 (previously cited, CN 108941584 A): teaches sintering high purity Mo powder with 500ppm oxygen or less, comprising a size of 2-6um, at 1800C-2000C to obtain a theoretical density of 96-98% (Example 1-3, see S2).
Naidu (previously cited, “The Cr-W (Chromium-Tungsten) System”): discloses the binary phase diagram (Fig. 1, Naidu), which shows an inherent miscibility gap between W and Cr in the phase diagram (see also Col. 1, Para. 1 of Naidu).
Venkatraman (previously cited, “The Cr-Mo (Chromium-Molybdenum) System”): discloses the binary phase diagram of Mo-Cr, which shows a miscibility gap (Fig. 1 showing an inherent Cr-Mo miscibility gap in the binary phase diagram; see also Col. 1, para. 1).
Tripathy (US 20200063243 A1): teaches a molybdenum alloy comprising up to 90wt% Mo, at least 1wt% rhenium and up to 10wt% of a metal including chromium (para. [0022]-[0025]), wherein a current assisted sintering process (SPS) conducted under vacuum wherein the coalescing powders of the material constituents are sintered with pressures up to 10MPa in the temperature range of 1200-1600C for less than an hour, and pressureless sintering for 1200-1600C for 4-6 hours (para. [0032]). Tripathy teaches wherein the sintering brings the structure up to about 100% density (para. [0031]).
Zhang (“An industrially feasible pathway for preparation of Mo nanopowder and its sintering behavior”): teaches wherein the introduction of increasing small amounts of nanosized Mo powder to micron powder enables sintering activation and increases densities for lowered sintering temperatures (Abstract; Section 3.2.4; Conclusions; Fig. 5(a)).
Petkovic-Luton (previously cited, US 4619699 A): teaches composite metal powders comprising a particle size less than 50um and an average grain size of 0.05-0.6um (50-600nm), wherein the metal powers comprise a 6b metal (Mo and Cr are 6b metal) and a refractory metal oxide, carbide, nitride, or boride (Mo and Cr are refractory metals) which are mechanically alloyed through milling (Col. 2, lines 37-50; Col. 3, line 25). One of ordinary skill in the art would appreciate that Petkovic-Luton therefore discloses nanocrystalline particles.
Petkovic-Luton teaches wherein such ultra-fine grains in the mechanically alloyed powder reduce slip and the concentration of slip bands, thereby alleviating the tendency of a material to form grain boundary cavities during consolidation, and also enabling texture free products and those free of oxide scales (Col. 3, lines 42-Col. 4, line 4).
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CATHERINE P. SMITH
Patent Examiner
Art Unit 1735
/CATHERINE P SMITH/ Examiner, Art Unit 1735
/KEITH WALKER/ Supervisory Patent Examiner, Art Unit 1735