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 .
Election/Restrictions
Claim 14 withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected product, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 12/23/2025.
Applicant's election with traverse of claims 1-13 in the reply filed on 12/23/2025 is acknowledged. The traversal is on the ground(s) that the 371 Unity of Invention restriction relied on the Lanfant reference which does not teach the relative density amended limitation. This is not found persuasive because a combination of references can still be used to read on the amended limitation wherein combination of references in the following Office Action reads on the argued limitation.
The requirement is still deemed proper and is therefore made FINAL.
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.
Claims 2-3 and 5-10 is 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.
Claim 2 recites “a shaped sintered silicon carbide body” which was already introduced in claim 1. Please correct antecedent basis.
Claim 3 recites “a carbon to silicon molar ratio” which was already introduced in claim 1. Please correct antecedent basis.
Claim 5 recites “a carbon in excess to oxygen molar ratio” which was already introduced in claim 1. Please correct antecedent basis.
Claim 1 recites “nanoparticles containing a silicon carbide core and a surface layer containing carbon and oxygen” which is narrower than Claim 6-8’s “nanoparticles comprising silicon and carbon”. The broader dependent claim limitation mapped to its original narrower independent claim limitation is indefinite.
Claim 9 recites “silicon carbide nanoparticles” wherein claim 9 depends from claim 8 which recites “said nanoparticles comprising silicon and carbon are alpha phase silicon carbide nanoparticles”. Claim 9 does not recite the “alpha phase” portion. Thus, the Examiner interprets claim 9 to refer to the “said nanoparticles comprising silicon and carbon” for the purpose that the instant specification has no express recitation that the alpha phase silicon carbon nanoparticles are produced by laser pyrolysis; the instant specification has only generally stated the laser pyrolysis synthesis of silicon carbide nanoparticles with no mention that the alpha phase is synthesized. Should the Applicant amend the claim to clarify the alpha phase nanoparticles are produced by laser pyrolysis, this 112b rejection will be converted to a written description/new matter 112a rejection.
Claim 10 recites “a sintered silicon carbide body” wherein claim 1 already introduces “a shaped sintered silicon carbide body”. Please correct antecedent basis.
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.
Claim 1-5, 7-8, 10-13 are rejected under 35 U.S.C. 103 as being unpatentable over Lanfant et al (“Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics”, 2015) and further in view of Yu et al (“Sintering Behavior of Spark Plasma Sintered SiC with Si-SiC Composite Nanoparticles Prepared by Thermal DC Plasma Process”, 2017) and Maeda et al (US-20190249059-A1)
Regarding claim 1 and 10, Lanfant teaches of a process for preparing a sintered silicon carbide body (p. 3370 R ¶ “Green bodies (2g)…”) comprising a step of sintering a sample comprising silicon carbide nanoparticles (p. 3376 R ¶ “C-SiC green bodies…”) containing a silicon carbide core (p. 3370 L ¶ “SiC nanopowders…”) and a surface layer containing carbon and oxygen (p. 3372 R ¶ “To summarize…”), said sample having at least 90 wt% being C or Si (Table 1) and carbon in excess to oxygen molar ratio that falls within the instant claimed range (molar ratio of 1 per 3.5/3.5 according to p. 3376 R ¶ “At first sight…”).
Lanfant teaches of carbon to silicon molar ratio lower than 1 (Table 1) and the silicon carbide nanoparticles with a particle diameter of 15.1 nm (Table 1). Lanfant does not expressly teach the carbon to silicon molar ratio is higher than 1 or the silicon carbide nanoparticles have a particle diameter in the instantly claimed range. In the same field of endeavor, Yu teaches of preparing silicon carbide nanoparticles with a 1.5:1 carbon to silicon ratio (p. 2 R ¶ “The micron-sized SiC…”) and further processed to achieve a particle diameter of 20-70 nm (p. 4 L-R “Nano-sized SiC powder…”). It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the silicon carbide nanoparticles of Lanfant with higher carbon content for increased shrinkage/densification for increased hardness end product as taught by Yu (p. 6-7 ¶ “Figure 8 presents…”).
Lanfant teaches of increasing density with increased sintering temperature (Table 2) and a pressure of 73 MPa (p. 3376 R ¶ “C-SiC green bodies…”), wherein the pressure to obtain the sintered silicon carbide body falls within the instantly claimed range. Yu also sees the temperature effect on density (Table 1) wherein holding time of the temperature also increased the density (Table 1 and 2). Neither reference teaches of the instantly claimed temperature and density. In related silicon carbide sintering art wherein there is more carbon than silicon [0038], Maeda teaches of sintering silicon carbide powder with pressure and temperature that falls within the instantly claimed range [0044]. It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use known sintering process parameters on a compositionally similar method as known parameters to increase density [0044] (“denser”).
Though Maeda does not expressly teach of a relative density or a reference density to compare their reported nominally produced densities, there is reasonable expectation of success from the combination of prior art that the process is substantially identical and would thus result in a product with substantially similar properties, such as relative density. It has been held that where the claimed and prior art products are identical or substantially identical in structure or are produced by identical or a substantially identical processes, a prima facie case of either anticipation or obviousness will be considered to have been established over functional limitations that stem from the claimed structure. In re Best, 195 USPQ 430, 433 (CCPA 1977), In re Spada, 15 USPQ2d 1655, 1658 ( Fed. Cir. 1990). The prima facie case can be rebutted by evidence showing that the prior art products do not necessarily possess the characteristics of the claimed products. in re Best, 195 USPQ 430, 433 (CCPA 1977).
Regarding claim 2, depending from claim 1, modified Lanfant has no additives (p. 3378 R “Summary”), wherein Lanfant does not consider the carbon coating as an additive.
Regarding claim 3, depending from claim 1, Lanfant teaches of a 0.46:1 carbon to silicon ratio (Table 1); modified Lanfant relies on Yu’s 1.5:1 carbon to silicon ratio (p. 2 R ¶ “The micron-sized SiC…”).The combination of Lanfant and Yu teaches a workable range broader than is instantly claimed. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. It would have been obvious to one having ordinary skill in the art to have determined the ideal carbon to silicon ratio as a relevant process parameter through routine experimentation in the absence of a showing of criticality.
Regarding claim 4, depending from claim 1, modified Lanfant relies on the nanoparticles of Yu which prepared their particles by ball milling Si powder with activated carbon (p. 2 R ¶ “The micron-sized SiC…”). Lanfant teaches of synthesizing the particles from a gaseous mixture, including the excess carbon embodiment by adjusting the gaseous mixture (p. 3370 L ¶ “SiC nanopowders…”). It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the gaseous mixture composition with more carbon content as a known technique to synthesize SiC nanoparticles.
Regarding claim 5, depending from claim 1, Lanfant teaches carbon in excess to oxygen molar ratio that falls within the instant claimed range (molar ratio of 1 per 3.5/3.5 according to p. 3376 R ¶ “At first sight…”). Overlapping ranges are prima facie evidence of obviousness. It would have been obvious to one having ordinary skill in the art to have selected the excess carbon to oxygen molar ratio that corresponds to the claimed range. See MPEP 2144.05.
Regarding claim 7, depending from claim 1, Lanfant teaches of the nanoparticles are beta phase silicon carbide nanoparticles (Table 1).
Regarding claim 8, depending from claim 1, modified Lanfant relies on the silicon carbide nanoparticle composition taught by Yu which comprises of both beta phase and alpha phase silicon carbide nanoparticles (Fig. 4, p. 4 R ¶ “the phase and structure…”), reading on the instant claim.
Regarding claim 11, depending from claim 1, Lanfant teaches the sintering is spark plasma sintering (p. 3370 R ¶ “Green bodies (2g)…”).
Regarding claim 12, depending from claim 1, Lanfant teaches of using a graphite mold (p. 3370 R ¶ “After dispersion…”) followed by sintering (p. 3370 R ¶ “Green bodies (2g)…”). Lanfant first converts the nanoparticles to a slurry to be slip-casted the graphite mold. In the same field of endeavor, Yu teaches filling a similar graphite mold without slurry slip-casting (p. 3 L ¶ “The mixed powders…”). It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to fill the mold with nanoparticles followed by sintering without slurry slip-casting as a known method in the art to process a shaped body.
Regarding claim 13, depending from claim 12, modified Lanfant relies on Yu’s powder in the mold method which is absent of discussing a pre-compaction step, inherently reading on the claimed limitation.
Claim 6 are rejected under 35 U.S.C. 103 as being unpatentable over Lanfant et al (“Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics”, 2015), Yu et al (“Sintering Behavior of Spark Plasma Sintered SiC with Si-SiC Composite Nanoparticles Prepared by Thermal DC Plasma Process”, 2017) and Maeda et al (US-20190249059-A1) as applied to claim 1 above, and further in view of Herlin-Boime et al (“Flame temperature effect on the structure of SiC nanoparticles grown by laser pyrolysis”, 2004).
Regarding claim 6, depending from claim 1, Lanfant teaches synthesizing the nanoparticles by laser pyrolysis from a gaseous mixture, including the excess carbon embodiment by adjusting the gaseous mixture (p. 3370 L ¶ “SiC nanopowders…”). Lanfant does not expressly teach of the nanoparticles are amorphous. In related laser pyrolysis nanoparticle synthesis art, Herlin-Boime teaches lowering the laser power synthesizes amorphous SiC (p. 65 R ¶ “XRD patterns…”; p. 66 R ¶ “Figures 5 and 6…”). It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to generate amorphous silicon carbide nanoparticles by adjusting the parameters of the laser pyrolysis synthesis is known in the art wherein the normal artisan would understand the compatibility of amorphous nanoparticles to be sintered into a ceramic product such as crystallizing amorphous glass via heat treatment.
Claim 9 are rejected under 35 U.S.C. 103 as being unpatentable over Lanfant et al (“Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics”, 2015), Yu et al (“Sintering Behavior of Spark Plasma Sintered SiC with Si-SiC Composite Nanoparticles Prepared by Thermal DC Plasma Process”, 2017) and Maeda et al (US-20190249059-A1) as applied to claim 8 above, and further in view of Yoshioka et al (US-20190043746-A1).
Regarding claim 9, depending from claim 8, Lanfant teaches synthesizing the nanoparticles by laser pyrolysis from a gaseous mixture, including the excess carbon embodiment by adjusting the gaseous mixture (p. 3370 L ¶ “SiC nanopowders…”) wherein carbon in excess to oxygen molar ratio that falls within the instant claimed range (molar ratio of 1 per 3.5/3.5 according to p. 3376 R ¶ “At first sight…”). Modified Lanfant relies on the silicon carbide nanoparticle composition taught by Yu which comprises of both beta phase and alpha phase silicon carbide nanoparticles (Fig. 4, p. 4 R ¶ “The phase and structure…”). Modified Lanfant does not expressly teach the alpha phase silicon carbide nanoparticles are produced by laser pyrolysis. In related silicon carbide art, Yoshioka teaches of using laser pyrolysis to synthesize SiC particles [0161] comprising both alpha phase and beta phase silicon carbide [0163, 175] after sintering. It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use nanoparticles produced by laser pyrolysis which were then sintered to alpha-phase as taught by Yoshioka and compatible with the sintering process as taught by Yu (p. 4 R ¶ “The phase and structure…”) as motivated by Yoshioka for high temperature or high thermal conductivity properties [0003].
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US-20150151976-A1 teaches the laser pyrolysis nanoparticle synthesis of carbon coated silicon carbide nanoparticles, reading on claim 4
US-20060147369-A1 teaches of generating amorphous SiC from laser pyrolysis
WO-2013190662-A1 teaches vapor phase processing to add carbon coating the silicon carbide particle followed by spark plasma sintering
KR-20130074707-A, US-7150850-B2 teaches organic liquid sol processing to achieve carbon coated silicon carbide particles
Cauchetier (2003) teaches the gas mixture laser pyrolysis to synthesis SiC with beta phase
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/STEVEN S LEE/Examiner, Art Unit 1741
/ERIN SNELTING/Primary Examiner, Art Unit 1741
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