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 .
Response to Amendment and Status of Claims
Applicant’s amendments to the claims, filed September 22, 2025, are acknowledged. Claims 2, 7 and 21 are amended, and Claim 10 is cancelled. No new matter has been added.
Claims 12-16, and 18, drawn to a process for fabricating a bulk magnet, Claim 19, drawn to a MnBi feedstock powder, and Claim 20, drawn to a bulk magnet, remain withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected Inventions II, III and IV, respectively, there being no allowable generic or linking claim. Applicant timely elected without traverse in the reply filed on December 12, 2022.
Claims 2-3, 5, 7-9, 11-16 and 18-21 are pending, and Claims 2-3, 5, 7-9, 11 and 21 are currently considered in this office action.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 7 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding Claim 7, the claim recites wherein “the non-magnetic metallic or polymeric material of the coating is selected from at least one of…a polymer”. Because the non-magnetic material is already recited as being a polymeric material, it is unclear what further limitation would be required by selection of a polymer, as currently claimed.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 2-3, 7 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Kim882 (previously cited, US 20160314882 A1) in view of Li (previously cited and cited by Applicant in IDS filed August 20, 2021, “Preparation and magnetic properties of anisotropic MnBi powders”), Lee (previously cited, US 20210183547 A1) and Kim134 (US 20160322134 A1).
Regarding Claim 2, Kim882 discloses a process for fabricating a quantity of MnBi feedstock powder (Fig. 1; para. [0033]-[0034]), comprising:
melting a selected ratio of manganese (Mn) metal and bismuth (Bi) metal with varied compositions (MnxB100-x, x=48.5-53.5 at. %) to form an alloy (para. [0018]);
melt-spinning the melted alloy at a wheel speed of 10-300m/s to form as-melt-spun, solidified ribbon flakes that include a crystalized MnBi phase therein (para. [0025]; para. [0027]-[0029]; 10-300m/s reads on the claimed 8-20m/s range; one of ordinary skill in the art would appreciate forming ribbons by melt-spinning creates solidified ‘ribbon flakes’);
annealing the as-cast melt-spun ribbon flakes to promote the formation of LTP MnBi phases (a-MnBi) therein to at least a purity of 90wt% (para. [0032]); and
comminuting the alloy after annealing to obtain comminuted powder particles with particle sizes of 3-5um for use in bulk permanent magnet manufacture by powder consolidation (para. [0018]; para. [0037]; Abstract).
Regarding the amounts of Mn and Bi in the alloy (ribbon) composition, the wheel speed and the particle size, 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.
Kim882 discloses annealing the as-spun ribbon flakes at about 270-350C and for up to 1 day (para. [0032]), but does not disclose annealing for 2-6 days.
Li teaches wherein the amount of LTP MnBi (alpha-MnBi) may be improved by increasing the annealing times (see Abstract; see Table 1).
For example, Lee teaches annealing a rapidly solidified Mn-Bi based ribbon at 270-330C for as long as 48 hours (2 days) in order to obtain the hard magnetic phase (see para. [0070]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have increased the annealing time to 2 days, as taught by Lee, for the invention disclosed by Kim882, in order to maximize and realize the largest amount of LTP MnBi phase possible (see teaching by Li and Lee 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. Additionally, the criticality has not been provided for the claimed range.
Kim882 does not disclose:
providing a non-magnetic second phase on the comminuted powder of the preceding step by depositing a coating consisting of a non-magnetic metallic or polymeric material on exterior surfaces of the comminuted powder particles, to provide feedstock powder consisting of the comminuted powder particles having the particle sizes and non-magnetic coating before bulk magnet manufacture by consolidation and provide the non-magnetic material between MnBi grains at grain boundaries after bulk magnet manufacture by powder consolidation wherein the non-magnetic material is present in an amount of 2wt% or less of bulk magnet weight.
Kim134 teaches adding a low melting point metal to the interface between particles by further milling comminuted powder with 0-10wt%, such as 1wt% and 2wt%, of a low melting point metal powder, such as Sn, Zn and Bi or an alloy thereof, prior to bulk consolidation, in order to improve coercive force, improve maximum energy product at a high temperature and improve thermal stability (para. [0017]-[0022]; para. [0051]-[0052]; para. [0058]; Fig. 1-2; pulverized MnBi powder reads on comminuted powder; Claim 11; Table 1 wherein Sn (low melting point metal powder) is included in 1wt% and 2wt%). One of ordinary skill in the art would appreciate that milling the MnBi comminuted powder with a low-melting point metal powder would coat the MnBi powder and deposit the low melting point metal on the surface of thereof because Sn and Bi are much softer materials than the MnBi powder. Kim134 teaches wherein the low-melting point metal remains as a grain boundary phase after consolidation at the interface between grains/crystal particles, preventing reversal of the magnetic field produced from a crystal particle from propagating to adjacent crystal particles (para. [0017]-[0018]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have milled the MnBi particles with 0-10wt%, including 1wt% and 2wt%, of a low melting point metal powder, such as one comprising Sn, Bi and Zn, or alloy thereof, and thereby formed a coating of the low melting point powder on the exterior surfaces of the comminuted MnBi powder particles prior to bulk magnet consolidation, and to have further formed a grain boundary phase of the low melting point metal at the interface between MnBi grains in the consolidated product, as taught by Kim134, for the invention disclosed by Kim288. One would be motivated to do this in order to prevent reversal of the magnetic field produced from a crystal particle from propagating to adjacent crystal particles, thereby improving coercive force, maximum energy product at a high temperature and thermal stability (see teaching above).
One of ordinary skill in the art would appreciate that a coating of Sn, Bi or Zn, or alloy thereof, reads on a coating which is non-magnetic and one consisting of a metallic material. The range 0-10wt%, including 1wt% and 2wt%, of low melting point metal powder reads on the claimed range of 0-2wt% of the non-magnetic material present in the bulk magnet weight. 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.
Further, regarding the limitations “wherein the particle sizes correspond substantially to grain size of the bulk permanent magnet” (see line 14-15 of Claim 2) and “provide the non-magnetic material between MnBi grains at grain boundaries after bulk magnet manufacture by powder consolidation wherein said non-magnetic material is present in an amount of 2wt% or less of bulk magnet weight” (lines 21-24 of Claim 2), these limitations are directed to the intended use of the feedstock powder and the manufacture of a bulk permanent magnet using the feedstock powder. The claim limitations directed to a process for fabricating a MnBi feedstock powder, including the structure (composition, particle size and the deposited non-magnetic coating) of the feedstock powder, have been met (see above).
Regarding Claim 3, Kim882 discloses wherein the melted alloy is rapidly solidified by melt spinning to form ribbon flakes (Kim882, para. [0027]).
Kim882 does not expressly disclose composition-uniform ribbon flakes, but Kim882 desires a specific composition and obtaining a uniform LTP magnetic phase (para. [0027]; para. [0030]).
It would have been obvious to have formed ribbon flakes with the desired composition throughout each ribbon, and therefore to have formed uniform compositioned ribbon flakes for the invention disclosed by Kim882, in order to subsequently form the uniform LTP magnetic phase.
Further, the method of forming the rapidly solidified ribbon flakes is the same 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 7, Kim134 discloses wherein the non-magnetic coating comprises at least one of Zn, Bi and Sn on the exterior surfaces of the comminuted powder particles (para. [0021]).
Regarding Claim 11, Kim882 discloses wherein the feedstock powder is incorporated as a component of a permanent magnet (Abstract).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Kim882 (previously cited, US 20160314882 A1) in view of Li (previously cited and cited by Applicant in IDS filed August 20, 2021, “Preparation and magnetic properties of anisotropic MnBi powders”), Lee (previously cited, US 20210183547 A1) and Kim134 (US 20160322134 A1), as applied to Claim 2 above, in further view of Xie (previously cited, “Effect of ball milling and heat treatment process on MnBi powders magnetic properties”) and Choi (previously cited, US 20150110664 A1).
Regarding Claim 5, Kim882, Li and Lee disclose wherein the alloy is annealed at 270-350C for 2 days (see Claim 2 above), and wherein the comminuted powder is ball milled or jet milled (Kim882, para. [0036]), but fail to disclose also annealing the comminuted powder at 270-350C for 2-5 days.
Xie teaches wherein MnBi powders subjected to ball milling are susceptible to decomposition. Xie teaches wherein annealing at 290C for 24hours after ball milling improves recovery of the magnetization (see Abstract).
Choi similarly teaches wherein heat treating milled MnBi powders at 250-300C (para. [0027]) increases the magnetic phase, alpha-MnBi (para. [0032]), and produces recovery of an alpha-MnBi phase after milling of 90% or more purity (see para. [0034] and para. [0027]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have annealed the milled powder at 250-300C, such as 290C, as taught by Xie and Choi, and further to have applied the annealing of Li and Lee (annealing for 2 days at 270-350C) to the comminuted/milled powder, for the invention disclosed by Kim882, Li and Lee, in order to recover magnetization lost to decomposition during milling and to obtain an MnBi-phase fraction of more than 90% (see teaching by Xie and Choi above). One would be motivated to use the times of Lee and Li (2 days) in order to recover and maximize the hard magnetic phase fractions, and therefore magnetization (see teaching above in Claim 2 wherein additional annealing time increases hard magnetic phase fraction).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Kim882 (previously cited, US 20160314882 A1) in view of Li (previously cited and cited by Applicant in IDS filed August 20, 2021, “Preparation and magnetic properties of anisotropic MnBi powders”), Lee (previously cited, US 20210183547 A1) and Kim134 (US 20160322134 A1), as applied to Claim 2 above, in further view of Cui (“Effect of composition and heat treatment on MnBi magnetic materials”) and Jin376 (US 20140132376 A1).
Regarding Claim 8, Kim882 discloses milling the powder from the as-cast material, and wherein the material before milling comprises a purity of 95% or more (para. [0032]; para. [0036]).
While Kim882 discloses wherein the powder is formed by milling a rapidly solidified ribbon formed by casting (para. [0025]), Kim882 fails to disclose wherein the powder is produced from comminuting an as-cast solidified ingot, and does not disclose a solidified ingot formed by cooling in a metallic ingot mold (see limitation requirements of option a) above in Claim 2).
Cui teaches wherein MnBi powder may be produced by casting an ingot, annealing the ingot, and subsequently pulverizing the powder (Sect. 2.1-2.2). Cui teaches wherein ribbon manufacturing is smaller scale (10g), wherein conventional arc or induction melting casting is preferred for larger capacity (kilogram or higher) setups and over ribbon manufacturing in terms of feasibility and cost effectiveness (Introduction, Pg. 375; section 2.1, sample preparation, arc melted and cast into buttons; section 2.2, heat treatment, “buttons were crushed, ground and sieved to powders and further heat treated”; section 2.3, ingots; Fig. 1, as-cast ingots).
Cui does not expressly disclose solidifying in a cooled metallic ingot mold.
Jin376 further teaches wherein an ultrafine grained MnBi starting material may be melted, casted, and rapidly solidified using a chilled metallic mold, which enables a compositionally more uniform MnBi phase (para. 0072]). One of ordinary skill in the art would appreciate that casting and rapidly chilling in a mold would produce an ingot.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have casted and rapidly solidified the MnBi material into an ingot, as taught by Cui and Jin376, and further to have rapidly solidified the MnBi melt with a chilled metallic mold, as taught by Jin376, for the invention disclosed by Kim882. One would be motivated to do this in order to produce larger (kilogram or higher) capacity setup with improved feasibility and cost effectiveness, and to also produce an ultrafine grained MnBi starting material which is compositionally more uniform (see teachings by Cui and Jin above).
Cui discloses wherein ingot casting enables larger capacity setups of a kilogram or higher (Pg. 375, para. 2), which reads on the claimed limitation (Claim 8) wherein the ingot is at least 1kg in weight. Additionally, one of routine skill in the art would be easily capable of forming differently sized and weighted ingots as a known and conventional method to tailor the amount of yield and/or production amount of powder. See MPEP 2144.04.A.IV.
Claims 9-10 are rejected under 35 U.S.C. 103 as being unpatentable over Kim882 (previously cited, US 20160314882 A1) in view of Li (previously cited and cited by Applicant in IDS filed August 20, 2021, “Preparation and magnetic properties of anisotropic MnBi powders”), Lee (previously cited, US 20210183547 A1) and Kim134 (US 20160322134 A1), as applied to Claim 2 above, in further view of Xie (previously cited, “Effect of ball milling and heat treatment process on MnBi powders magnetic properties”) and Choi (previously cited, US 20150110664 A1).
Regarding Claim 9, Kim882 discloses milling the powder from the as-cast material, and wherein the material before milling comprises a purity of 95% or more (para. [0032]; para. [0036]).
Kim882 however fails to disclose the purity of the powder after milling.
Xie teaches wherein MnBi powders subjected to ball milling are susceptible to decomposition, but may be subsequently annealed at 290C for 24hours after ball milling to improve recovery of the magnetization (see Abstract).
Choi similarly teaches wherein heat treating milled MnBi powders at 250-300C increases the magnetic phase (alpha-MnBi) and produces recovery of an alpha-MnBi phase after milling to be 95wt% or more (para. [0027]; [0014], greater than 95wt%). One of ordinary skill in the art would be able to convert and appreciate that 95wt% or more alpha-MnBi phase reads on the claimed 95vol% or higher.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have annealed the milled/comminuted powder at 250-300C, as taught by Xie and Choi, and therefore (Claim 9) obtained an MnBi-phase fraction of more than 95vol% in the powder, for the invention disclosed by Kim882, Li and Lee. One would be motivated to anneal at these temperatures and obtain a MnBi phase fraction of 90vol% or more in order to recover magnetization lost to decomposition during milling, and to maximize the quantity of high alpha MnBi phase powder available to be used for permanent magnets (see teaching by Xie and Cho above).
Regarding Claim 10, Kim882 discloses wherein the feedstock powder contains a high-purity a-MnBi phase (para. [0032]), and Kim134 discloses wherein the non-magnetic coating comprises at least one of Zn, Bi and Sn on the exterior surfaces of the comminuted powder particles (para. [0021]).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Kim882 (previously cited, US 20160314882 A1) in view of Li (previously cited and cited by Applicant in IDS filed August 20, 2021, “Preparation and magnetic properties of anisotropic MnBi powders”), Lee (previously cited, US 20210183547 A1), Cui (“Effect of composition and heat treatment on MnBi magnetic materials”), Jin376 (US 20140132376 A1) and Kim134 (US 20160322134 A1).
Regarding Claim 21, Kim882 discloses a process for fabricating a mass quantity of MnBi feedstock powder (Fig. 1; para. [0033]-[0034]; see Abstract wherein sufficient powder is produced to form a sintered magnet), comprising:
melting a selected ratio of manganese (Mn) metal and bismuth (Bi) metal with varied compositions (MnxB100-x, x=48.5-53.5 at. %) to form an alloy (para. [0018]);
rapidly solidifying the melted alloy by casting to form a solidified material that includes a crystalized MnBi phase (para. [0025]; para. [0027]-[0029]);
annealing, in a single annealing step, the as-cast material at about 270-350C for a time to form LTP MnBi phases (a-MnBi) therein to at least a purity of 90wt% (para. [0032]); and
comminuting the solidified material after annealing to obtain comminuted powder particles with particle size of 5um or less for use in bulk permanent magnet manufacture by powder consolidation (para. [0018]; para. [0037]; Abstract).
Regarding the composition and particle size, 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.
Kim882 discloses annealing the alloy material at about 270-350C and for up to 1 day (para. [0032]), but does not disclose annealing for 2-6 days.
Li teaches wherein the amount of LTP MnBi (alpha-MnBi) maybe be improved by increasing the annealing times (see Abstract; see Table 1).
For example, Lee teaches annealing a rapidly solidified Mn-Bi based material at 270-330C for as long as 48 hours (2 days) in order to obtain the hard magnetic phase (see para. [0070]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have increased the annealing time to 2 days, as taught by Lee, for the invention disclosed by Kim882, in order to maximize and realize the largest amount of LTP MnBi phase possible (see teaching by Li and Lee 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. Additionally, the criticality has not been provided for the claimed range.
Kim882 discloses rapid solidification by casting to form the MnBi material in the form of a ribbon (para. [0025]), but does not disclose solidifying in a cooled metallic ingot mold to form an as-cast solidified ingot body.
Cui teaches wherein MnBi powder may be produced by casting an ingot, annealing the ingot, and subsequently pulverizing the powder (Sect. 2.1-2.2). Cui teaches wherein ribbon manufacturing is smaller scale (10g), wherein conventional arc or induction melting casting is preferred for larger capacity (kilogram or higher) setups and over ribbon manufacturing in terms of feasibility and cost effectiveness (Introduction, Pg. 375; section 2.1, sample preparation, arc melted and cast into buttons; section 2.2, heat treatment, “buttons were crushed, ground and sieved to powders and further heat treated”; section 2.3, ingots; Fig. 1, as-cast ingots).
Cui does not expressly disclose solidifying in a cooled metallic ingot mold.
Jin376 further teaches wherein an ultrafine grained MnBi starting material may be melted, casted, and rapidly solidified using a chilled metallic mold, which enables a compositionally more uniform MnBi phase (para. 0072]). One of ordinary skill in the art would appreciate that casting and rapidly chilling in a mold would produce an ingot.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have casted and rapidly solidified the MnBi material into an ingot, as taught by Cui and Jin376, and further to have rapidly solidified the MnBi melt with a chilled metallic mold, as taught by Jin376, for the invention disclosed by Kim882. One would be motivated to do this in order to produce larger (kilogram or higher) capacity setup with improved feasibility and cost effectiveness, and to also produce an ultrafine grained MnBi starting material which is compositionally more uniform (see teachings by Cui and Jin above).
Cui discloses wherein ingot casting enables larger capacity setups of a kilogram or higher (Pg. 375, para. 2), which reads on the claimed limitation wherein the ingot is at least 1kg in weight. Additionally, one of routine skill in the art would be easily capable of forming differently sized and weighted ingots as a known and conventional method to tailor the amount of yield and/or production amount of powder. See MPEP 2144.04.A.IV.
Kim882 does not disclose:
providing a non-magnetic second phase on the comminuted powder of the preceding step by depositing a coating consisting of a non-magnetic metallic or polymeric material on exterior surfaces of the comminuted powder particles, to provide feedstock powder consisting of the comminuted powder particles having the particle sizes and non-magnetic coating before bulk magnet manufacture by consolidation and provide the non-magnetic material between MnBi grains at grain boundaries after bulk magnet manufacture by powder consolidation wherein the non-magnetic material is present in an amount of 2wt% or less of bulk magnet weight.
Kim134 teaches adding a low melting point metal to the interface between particles by further milling comminuted powder with 0-10wt%, such as 1wt% and 2wt%, of a low melting point metal powder, such as Sn, Zn and Bi or an alloy thereof, prior to bulk consolidation, in order to improve coercive force, improve maximum energy product at a high temperature and improve thermal stability (para. [0017]-[0022]; para. [0051]-[0052]; para. [0058]; Fig. 1-2; pulverized MnBi powder reads on comminuted powder; Claim 11; Table 1 wherein Sn (low melting point metal powder) is included in 1wt% and 2wt%). One of ordinary skill in the art would appreciate that milling the MnBi comminuted powder with a low-melting point metal powder would coat the MnBi powder and deposit the low melting point metal on the surface of thereof because Sn and Bi are much softer materials than the MnBi powder. Kim134 teaches wherein the low-melting point metal remains as a grain boundary phase after consolidation at the interface between grains/crystal particles, preventing reversal of the magnetic field produced from a crystal particle from propagating to adjacent crystal particles (para. [0017]-[0018]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have milled the MnBi particles with 0-10wt%, including 1wt% and 2wt%, of a low melting point metal powder, such as one comprising Sn, Bi and Zn, or alloy thereof, and thereby formed a coating of the low melting point powder on the exterior surfaces of the comminuted MnBi powder particles prior to bulk magnet consolidation, and to have further formed a grain boundary phase of the low melting point metal at the interface between MnBi grains in the consolidated product, as taught by Kim134, for the invention disclosed by Kim288. One would be motivated to do this in order to prevent reversal of the magnetic field produced from a crystal particle from propagating to adjacent crystal particles, thereby improving coercive force, maximum energy product at a high temperature and thermal stability (see teaching above).
One of ordinary skill in the art would appreciate that a coating of Sn, Bi or Zn, or alloy thereof, reads on a coating which is non-magnetic and one consisting of a metallic material. The range 0-10wt%, including 1wt% and 2wt%, of low melting point metal powder reads on the claimed range of 0-2wt% of the non-magnetic material present in the bulk magnet weight. 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.
Further, regarding the limitations “wherein the particle sizes correspond substantially to grain size of the bulk permanent magnet” (see line 14-15 of Claim 2) and “provide the non-magnetic material between MnBi grains at grain boundaries after bulk magnet manufacture by powder consolidation wherein said non-magnetic material is present in an amount of 2wt% or less of bulk magnet weight” (lines 21-24 of Claim 2), these limitations are directed to the intended use of the feedstock powder and the manufacture of a bulk permanent magnet using the feedstock powder. The claim limitations directed to a process for fabricating a MnBi feedstock powder, including the structure (composition, particle size and the deposited non-magnetic coating) of the feedstock powder, have been met (see above).
Response to Arguments
Applicant’s arguments, filed September 22, 2025, with respect to Claim 2, and dependent claims thereof, and Claim 21, rejected under 35 U.S.C. 103 over Kim882 in view of Li, Lee, and Kishimoto (see Claim 2), and over Kim882 in view of Li, Lee, Cui, Jin376 and Kishimoto (see Claim 21), have been fully considered and are persuasive in view of Applicant’s amendments to the claims further limiting the coating composition. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made over Kim882 in view of Li, Lee, and Kim134 (see Claim 2), and over Kim882 in view of Li, Lee, Cui, Jin376 and Kim134 (see Claim 21), as detailed above.
Applicant’s arguments directed to Kishimoto is deemed moot in view of the new ground(s) of rejection.
Regarding Kim882:
Applicant argues that Kim882 broadly discloses 10-300m/s, and prefers a range of 60-70m/s, in order to produce the nano-scale (50-100nm) grain structure. Applicant argues that Kim expressly discloses the anneal time to be 3-24 hours, and therefore teaches away from using a slower wheel speed of 8-20m/s in combination with a lengthened anneal time to produce the claimed purity of 90vol% (Remarks, pg. 10).
Applicant argues that Kim134 confirms a wheel speed of 55-75m/s, and expressly teaches speeds below 55m/s in regards to grain coarsening (Remarks, pg. 10).
These arguments are not found persuasive.
As stated before, the broader disclosure of Kim882 discloses the claimed range (10-300m/s reads on the claimed 8-20m/s) and “patents are relevant as prior art for all the contain” (MPEP 2123.I). Regarding the preferred embodiment of 60-70m/s of Kim882, “disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments” (see MPEP 2123.II), as alleged by Applicant. The disclosure of Kim882 does not recite wherein a grain size of 50-100nm is only obtainable within the 60-70m/s wheel speed. The claimed wheel speeds are expressly disclosed by Kim882 and the claimed grain sizes are expressly disclosed by Kim882. The claim limitations have therefore been met.
Further, Applicant has not provided a showing of criticality of the claimed range, and has not explained why the invention of Kim882 would be unable to obtain the claimed grain sizes when the method steps of Kim882 are simultaneously identical to those claimed. Additionally, Zhang (“High energy product of MnBi by field annealing and Sn alloying”) demonstrates, for example, wherein a wheel speed of 20m/s used for forming a MnBi ribbon produces grains of 59nm and 62nm (Pg. 2, Col. 1, para. 3, 20m/s; Pg. 3, Col. 1, Para. 1), such that it would be understood by one of ordinary skill in the art that the disclosed parameters for wheel speed by Kim882 would obtain the grain sizes claimed (50-100nm) and also already disclosed by Kim882.
Regarding Kim134, this reference was not previously applied and is not currently applied to teach wheel speed, and the wheel speeds are already disclosed by Kim882. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Regarding Lee and Li:
Applicant argues Kim882 fails to provide a technical basis or motivation to suggest the claimed method steps, and that the applied references (Lee and Li) teach away from the combination (Remarks, pg. 10-11).
Specifically, Applicant argues that Lee and Li disclose different initial alloy compositions and that the anneal times are contrary to Kim882, and one of ordinary skill in the art of magnetic powder processing efficiency would not be led to increase annealing from hours to days as claimed. Applicant additionally argues that Lee and Li do not provide a motivation for the combination or to modify Kim’s short annealing times for use with high melt spinning wheel speeds (Remarks, Pg. 12).
Applicant further argues that there is no reasonable expectation of success because Lee uses a different wheel speed and yields unpredictable phase fractions, and a low emu/g value. Applicant similarly argues that Li does not disclose the pellet side of the sample and that the results are therefore unpredictable and also comprise a low emu/g value (Remarks, pg.12-13).
These arguments are not found persuasive.
Kim882 only discloses a preferred range of 3-24 hours, and does not teach away from longer annealing times, and therefore the teachings of Lee and Li are applicable, and a teaching of an expanded range for heat treatment duration does not contrast with the disclosure of Kim882. Further, the composition of Lee (para. [0022], MnxBi100-x-ySby wherein x is 48-56 and y is 0-3) overlaps that of Kim882 (para. [0018], MnxBi100-x, wherein x is 45-55). Additionally, the composition of Li (Sect. 2, Experimental, Mn50Bi50), also overlaps that of Kim882, and the annealing times taught by Lee and Li are therefore further applicable.
Regarding motivation, Li teaches wherein the amount of LTP MnBi (alpha-MnBi) may be improved by increasing the annealing times (see Abstract; see Table 1), and Lee demonstrates that the claimed time and temperatures produce the claimed fraction of hard magnetic phase (Table 1, 100%). Thus, motivation is provided by Li, and further demonstration of success for producing the claimed phase fraction is provided by Lee, and it would be obvious to one of ordinary skill in the art to combine the teachings Li and Lee with Kim882 with an expectation of success of providing a higher LTP MnBi phase fraction. Neither reference recites a limit to this teaching (obtaining higher LTP phase fraction through longer annealing times) from initial grain size and/or wheel speed. Moreover, one of ordinary skill in the art could easily extrapolate the data of Li which clearly shows an increasing trend in the amount of LTP MnBi phase fraction with increasing annealing time.
Regarding the wheel speed of Lee, Kim882 already discloses the claimed wheel speed, and Lee does not contain disclosure such that the taught annealing times would only be useful for a certain range of wheel speeds or further, that slow wheel speeds would require shorter annealing times. Applicant argues that Lee and Li disclose low emu/g values, however, this is not a currently claimed feature and Lee and Li are not applied to teach a particular value of emu/g.
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., emu/g value) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
Applicant argues the combination of Li and Lee with Kim882 ignores the unpredictable adverse effect of grain coarsening during the low temperature annealing step. Applicant argues the unpredictable nature of grain coarsening demonstrates nonobviousness (Remarks, Pg. 13).
This argument is not found persuasive.
Lee and Li provide proper motivation for the combination with Kim882 (see above response). The grain size after annealing is not a currently claimed feature, and therefore this argument is not commensurate in scope with the claims. Further, the method steps are met by Kim882, Li and Lee, and the predictability is that of increasing the LTP phase fraction not the grain size after annealing. Moreover, one of ordinary skill in the art would appreciate the grain coarsening to be the same as the instant invention because the processing limitations have been met.
Regarding Xie and Choi:
Applicant argues that Kim882, Li and Lee do not disclose prolonged milling after pulverization (Remarks, Pg. 14).
Applicant argues that Xie only teaches short annealing times, and argues that Choi teaches a short annealing of the MnBi ingot and that the phase fraction of the annealed phase fraction is outside the claimed range (Remarks, Pg. 15).
Applicant argues that Examiner cannot use only the second heat treatment but must incorporate the full heating schedule of Choi to use the teachings of Choi (Remarks, Pg. 15).
These arguments are not found persuasive.
The rejection relies on multiple teachings. Xie teaches annealing after milling to recover lost magnetization from milling, Choi teaches annealing after milling to recover and increase LTP phase fraction lost during milling, and Li teaches that longer anneal times increases the LTP phase fraction. Thus, it would be obvious to one of ordinary skill in the art to anneal after milling and for longer annealing times in order to increase the LTP phase fraction lost during milling and thereby improve magnetization. Applicant fails to find fault in or acknowledge the motivations provided by the references in the rejection. Further, the differences noted by the Applicant are not limiting to the applied teachings of the reference, and the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). Further, the annealing times and temperatures of Choi per the ingot (266-350C, 5 hours or more) appear to overlap and are not mutually exclusive from that of Kim882, Lee and Li (para. [0032], 280-340C; 3-24hours (or more – see teaching by Lee and Li)).
Applicant argues that Kim882 fails to disclose large-scale quantity and purity per processing batch, argues that Li uses laboratory scale pellets, argues that Lee produces gram quantities of melt-spun ribbon, and that no pathway for scale-up is provided by these references (Remarks, Pg. 15).
Applicant argues that Cui only demonstrates a gram-scale arc-melted cast button and does not disclose cooled metallic ingot mold, and discloses heating in two-steps and for compositions outside the claimed range. Applicant argues that the inclusion of the teaching of Cui is unpredictable for combination (Remarks, Pg. 16).
Applicant argues that Jin376 does not disclose batch size and is not related to the claimed production amount of 1kg or more per batch (Remarks, Pg. 16).
These arguments are not found persuasive.
The claims do not require a bulk amount of melt-spun ribbons, and this argument directed towards the melt spun ribbons (see Claim 2) is not commensurate in scope with the claims. Regarding ingots, while the examples of Cui are small-scale, Cui still teaches wherein induction melt casting produces kilogram or higher capacities. Thus, Cui discloses a route for scale-up by induction melting kilogram quantities. Further in regards to the scale-up of the ingot, it is routine skill in the art to change the size of the ingot and one of ordinary skill in the art would be aware of the quench rate for differently sized ingots.
The annealing parameters and composition of Cui are not relied upon as teachings in the rejection, as these features are already disclosed by Kim882 and taught by Li and Lee. Cui is applied to teach the use of an ingot instead of melt-spun ribbons and the amount of MnBi produced from the ingot method. Further, Jin376 is relied upon to teach the use of a chilled mold for the MnBi ingot casting method, as opposed to Cui, and Jin376 is not applied to teach batch quantity. Kim882, Li and Lee are also not applied to teach the batch quantity (Lee and Li teach extended annealing times). In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Cao2018 (previously cited, “Effects of intergranular phase on the coercivity for MnBi magnets prepared by spark plasma sintering”): teaches wherein MnBi powder used for bulk permanent magnets comprises non-magnetic intergranular (at the grain boundary) phases of Bi, which improves coercivity due to magnetic isolation effects (Introduction; Abstract).
Nguyen (previously cited, “Effect of pre-alloy composition on the content of ferromagnetic phase of MnBi melt spun ribbons”): teaches typical melt-spinning wheel speeds of 20 m/s.
Guo (previously cited and cited by Applicant in IDS filed August 20, 2021, “Formation of MnBi ferromagnetic phases through crystallization of the amorphous phase): teaches wherein rapidly solidified melt quenched MnBi may be transformed from the as-quenched amorphous state to form 95wt% or more alpha MnBi phase (LTP phase), with the remaining 5wt% being Bi phase, by annealing at 543K (see Abstract; see Pg. 6067-6068, Results and Discussion, Para. 1; 543K is 270C). One of ordinary skill in the art would be able to convert between weight% and volume%, and appreciate that 95wt% or more LTP phase would read on the claimed 90vol% or more LTP phase.
Guo also teaches melt quenching an ingot in the same manner of the instant invention, wherein MnBi ingots may be prepared by melting the appropriate amounts of Mn and Bi and water-cooling on a copper boat (i.e., mold) (see Pg. 6068, Experimental Methods, Para. 1).
Cao (previously cited, “Microstructure and magnetic properties of MnBi alloys with high coercivity and significant anisotropy prepared by surfactant assisted ball milling”): teaches wherein MnBi powders may be used for bonded MnBi permanent magnets as an alternative to rare earth magnets, which use critical rare earth elements (see Introduction).
Ramlam (previously cited, “Preparation and characterization of bakelite bonded magnet NdFeB used for electric generator”): teaches wherein Bakelite may be used as a suitable binder for bonded permanent magnets because it has superior heat resistance and produce magnetic materials with higher heat resistance (see Pg. 2, Introduction).
Jin (cited above, US 20140291296 A1, teachings previously but not currently relied upon): teaches a hard magnetic particle, including MnBi, and also teaches decorating the hard magnetic particles with nonmagnetic grain boundary barrier material, such as Zn, Sn an Bi, in order to impede domain wall movement, thereby enhancing magnetic properties such as coercivity (para. [0063]-[0064]). One of ordinary skill in the art would appreciate that decorating reads on coating (see para. [0066]-[0067], wherein particles are decorated ‘or coated’ with smaller size particles; see Fig. 9, coating method 910).
Jensen (“Optimizing composition in MnBi permanent magnet alloys”): teaches annealing MnBi melt-spun ribbons at 290C for five days (2.1, Sample Preparation).
Kishimoto (previously cited, US 5648160 A): teaches wherein MnBi particles are coated with an inorganic compound, including a carbide or nitride of Bi or Mn, in an amount of at least 1wt%, in order to improve corrosion resistance (Col. 10, lines 45-47 and 55-60; Col. 3, lines 5-8, 1-50wt%). Kishimoto further teaches wherein CVD, and other conventional methods such as sol-gel, precipitation, microcapsulation, pyrolysis and mechanochemical methods, may be further used to coat MnBi particles with other substances such as an inorganic compound of a metal (Col. 10, lines 61- Col. 11, lines 13).
Yokota (JP 2019054128 A, English Machine Translation provided): teaches wherein MnBi alloys may comprise 0.1-5wt% of an additive element or alloy, including Zn, which improves magnetic properties and corrosion resistance, and wherein the additive alloy may be added at the time of pulverization and present as a coating on the MnBi-based alloy particle (para. [0017]-[0018]).
Irie (previously cited, JP 2017135267 A1, see updated English machine translation): teaches the addition of a nonmagnetic metal binder to feedstock powder in order to increase the relative density of the magnet, and increase residual magnetic flux density without reducing the coercive force (para. [0011]-[0013]). Irie teaches wherein, prior to bulk consolidation, comminuted MnBi powder is mixed with the non-magnetic metal binder powder, such as one comprising Bi, Sn and Zn, and wherein that metal binder is disposed between MnBi particles, and further, exists as a grain boundary phase between particles to magnetically separate the magnetic particle (Abstract; para. [0011]; para. [0024]-[0025]; para. [0034]; see para. [0035] wherein mixing occurs prior to bulk consolidation).
Irie teaches mixing MnBi magnetic powders with the low-melting point metal by mixing at a temperature, such as 50-400C, and above the melting point of the low-melting point metal, in order to provide a powder with good fluidity (para. [0034]; see para. [0035], wherein heated milling process produces a powder used to fill a mold which is then consolidated). One of ordinary skill in the art would appreciate that mixing with a melted low-melting point metal would produce a coating of low-melting point metal over the entire exterior surface of the magnetic particles because the magnetic particles will have remained unmelted.
Wang (US 20130266473 A1): teaches forming a metallic coating on a magnetic particle prior to bulk consolidation wherein the coating is formed via mechanical milling, physical vapor deposition (PVD) or chemical vapor deposition (CVD) (para. [0005]). Thus, Wang recognizes the art equivalence of mechanical milling with PVD and CVD for coating a particle with a metal powder.
Zhang (“High energy product of MnBi by field annealing and Sn alloying”): demonstrates wherein a wheel speed of 20m/s for forming a MnBi ribbon results in grains of 59nm and 62nm (Pg. 2, Col. 1, para. 3, 20m/s; Pg. 3, Col. 1, Para. 1).
Choi (cited above, US 20150110664 A1, further teachings): teaches forming MnBi material at scalable and industrial quantities greater than about 1kg in a single process batch by forming an ingot, annealing, milling, and further heat treatment (para. [0015]; Fig. 1). Choi discloses annealing at 266C (which is very close to the claimed 270) for 8 hours or more and at 266-350C for 5 hours or more (which is inclusive of 2-6 days as Choi does not disclose an upper limit), and then repeating annealing at 250-300C after milling to increase LTP phase fraction (para. [0011]-[0014]).
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CATHERINE P SMITH whose telephone number is (303)297-4428. The examiner can normally be reached Monday - Friday 9:00-4:00 MT.
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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