DETAILED ACTION
Response to Amendment
The Amendment filed 15 April 2026 has been entered. Claims 1, 2, and 4-9 remain pending in the application. Claim 3 has been canceled. No new claims have been added. Applicant's amendments to the claims have overcome the 112(b) rejections previously set forth in the Non-Final Rejection mailed 15 January 2026.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 2, and 4-9 are rejected under 35 U.S.C. 103 as being unpatentable over EP3179487 of Kamata.
Claim 1 as currently amended claims a R-T-B sintered magnet comprising a main phase in the form of a R2Fe14B intermetallic compound and a grain boundary phase, wherein the magnet has a composition consisting essentially of 12.5 to 17.0 atom% of R which is at least one element selected from rare earth elements and essentially contains Nd, 4.5 to 5.5 atom% of B, at least 70 atom% of T which is Fe and Co, where at least 90 atom% of T is Fe, 0.1 to 3.0 atom% of Mi which is at least one element selected from Al, Mn, Ni, Cu, Zn, Ga, Pd, Ag, Cd, Sb, Pt, Au, Hg, and Bi, 0.01 to 0.5 atom% of M2 which is at least one element selected from Si, Ge, In, Sn, and Pb, 0.05 to 1.0 atom% of M3 which is at least one element selected from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, and up to 0.8 atom% of O, and the balance of C, N and incidental impurities, the grain boundary phase contains i) a R-T-(M1, M2) phase having higher R, M1 and M2 concentrations than the main phase, ii) a R-M2-C phase having higher R and M2 concentrations than the R-T-(M1, M2) phase, and a higher C concentration than the main phase, and iii) a M3 carbide phase, but the grain boundary phase does not contain a R1.1T4B4 compound phase or a M3 boride phase.
Kamata discloses a rare earth-iron-boron based sintered magnet and method for manufacturing such in the same field of endeavor as the claimed invention. Kamata teaches an R value of 12 to 17 atom%, where R is two or more elements selected from rare earth elements including Y and Nd and Pr, Para[0028]. This overlaps with the range for R of the claimed invention. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05.
Kamata also teaches a range of 0.1 to 3.0 atom% M1 where M1 is one or more elements selected from Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb and Bi, Para[0016]. M1 of Kamata corresponds to M1 and M2 of the claimed invention. The claimed invention states a range for M1 of 0.1 to 3.0 atom%, and a range for M2 of 0.01 to 0.5 atom%. This means a combined range for M1 + M2 would be 0.11 to 3.5 atom%. This overlaps with the range of 0.1 to 3.0 atom% taught by Kamata, Para[0028]. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05.
M3 of the claimed invention corresponds to M2 of Kamata. Kamata teaches a range for M2 of 0.05 to 0.5 atom%, where M2 is at least one from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, Para[0028]. This overlaps with the range of 0.05 to 1.0 atom% M3 of the claimed invention, where M3 is at least one element selected from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05.
Kamata teaches a range of atom% B from 4.8+2*m to 5.9+2*m, where m is the atomic % of M2. Kamata teaches a range for M2 of 0.05 to 0.5 atom%, Para[0016]. This means the lowest possible value for B would be 4.9, corresponding to an m of 0.05, and the largest possible value for B would be 6.9, corresponding to an m of 0.5. This range of 4.9 to 6.9 atom% B overlaps with the 4.5 to 5.5 atom% range of the claimed invention. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05.
Kamata teaches 1.5 atom% or less of O and the balance Fe, Para[0020]. This overlaps with the claimed ranges of up to 0.8 atom% O and at least 70 atom% T, which is Fe and Co. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05.
Kamata also teaches that the grain boundary phase may contain an R'-M1 " phase containing at least 50 at% of R' wherein M1 " is at least one element selected from the group consisting of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi. At the grain boundary triple junction, there are formed an R oxide phase, R carbide phase, R nitride phase, or R oxyfluoride phase of high-melting compound or a mixture of such phases and M2 boride phase, Para[0020]. This means that the boride phase is optional and may be replaced by the R carbide phase.
Additionally, Kamata discloses the same or similar method for producing the R-T-B magnet as the claimed invention. Kamata discloses a method that generally involves coarse grinding of a mother alloy, fine milling, compaction, and sintering, Para[0045]. These are the same general steps described in the instant specification. Furthermore, Kamata discloses the same heat treatment at 700 to 1200 °C, Para[0046], for the mother alloy; the same particle sizes for the coarse and fine powder, Para[0047]; the same sintering temperature, 900 to 1250 °C, and time, 0.5 to 5 hours, Para[0049]; the same high temperature heat treatment, 700 to 1000 °C, Para[0050] ; and the same low temperature heat treatment, 400 to 600 °C, Para[0052] as the claimed invention. Therefore, Kamata discloses a composition and method which do not appear to be patentably distinct from the claimed invention. Where 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 and "Products of identical chemical composition cannot have mutually exclusive properties", see MPEP 2112.01. Thus, all physical properties of the claimed invention, including the microstructural phases of the magnet, are inherently present in Kamata. Therefore, Kamata reads on all limitations of claim 1.
Claim 2 further limits claim 1 by stating that the content of C is 0.1 to 1.0 atom%.
Kamata teaches carbon in the range of 0.5 atom% or less, Para[0020]. This overlaps with the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05. Therefore, Kamata reads on all limitations of claim 2.
Claim 4 further limits claim 1 by claiming that the phase in the grain boundary phase contains 25 to 35 atom% R, 1 to 7 atom% of M1, more than 0 to 5 atom% of M2, and the balance containing T.
Kamata teaches that the grain boundary phase is composed of an amorphous and/or nanocrystalline R'-(Fe,Co)-M1 ' phase consisting essentially of 25 to 35 at% of R', 2 to 8% of M1 ' wherein M1 ' is at least one element selected from the group consisting of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi, up to 8 at% of Co, and the balance of Fe, Para[0020]. As stated above, M1 of Kamata corresponds to M1 and M2 of the claimed invention. The range for M1 + M2 for claim 4 would be more than 1 to 12 atom%. The ranges claimed for R, and M1 + M2 overlap with the ranges taught in Kamata. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05. Thus, Kamata reads on all limitations of claim 4.
Claim 5 further limits claim 1 by stating that the atom concentration of M2 divided by the atom concentration of M1 is greater than 0.6 and less than 3.0.
As stated above, M1 of Kamata corresponds to M1 and M2 of the claimed invention. Kamata teaches a concentration of 2 to 8 atom % M1 in the R-T-M1 phase, Para[0020]. One of ordinary skill in the art could select two elements from M1 of Kamata. One element, for example, Al, could be from M1 of the claimed invention, and the other element, for example, Sn, could be from M2 of the claimed invention. Since Kamata teaches that these two elements can be in any combination of amounts as long as the total is in the range of 2 to 8 atom%, Para[0020], one of ordinary skill in the art could select concentrations for M1 and M2 elements that read on the claimed range of 0.6 < [M2]/[M1] < 3.0. For example, a concentration of Al of 2 atom% and a concentration of Sn of 5 atom% would result in an M1 + M2 of 7 atom%. This falls within the range of 2 to 8 atom% taught by Kamata, Para[0020]. The value of [M2]/[M1] in this instance would be 2.5. This falls within the range of 0.6 to 3.0 of the claimed invention. All combinations of M1 and M2 of the claimed invention that would result in a value for [M2]/[M1] in the claimed range are covered by the combinations taught by Kamata, Para[0020]. Therefore, Kamata reads on all limitations of claim 5.
Claim 6 further limits claim 1 by stating that M2 contains Sn, and the content of M2 is 0.05 to 0.3 atom%.
As stated above M2 of the claimed invention is included in M1 of Kamata. Sn is included in M1 of Kamata in a range of 0.1 to 3.0 atom%. This overlaps with the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05. Therefore, Kamata reads on all limitations of claim 6.
Claim 7 further limits claim 1 by stating that M2 contains Sn, and the grain boundary phase contains a R-Sn-C phase as the R-M2-C phase.
Kamata teaches that the grain boundary phase may contain an R'-M1 " phase containing at least 50 at% of R' wherein M1 " is at least one element selected from the group consisting of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi. At the grain boundary triple junction, there are formed an R oxide phase, R carbide phase, R nitride phase, or R oxyfluoride phase of high-melting compound or a mixture of such phases and M2 boride phase, Para[0020]. The R-Carbide taught in Kamata corresponds to the R-M2-C phase of claim 7. Therefore, Kamata reads on all limitations of claim 7.
Claim 8 further limits claim 1 by stating that the R-M2-C phase is a R-(M1)M2-C phase further containing element M1, the R-(M1)M2-C phase having a higher M1 concentration than the M1 concentration in the main phase grains.
Kamata teaches that the grain boundary phase may contain an R'-M1 " phase containing at least 50 at% of R' wherein M1 " is at least one element selected from the group consisting of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi. At the grain boundary triple junction, there are formed an R oxide phase, R carbide phase, R nitride phase, or R oxyfluoride phase of high-melting compound or a mixture of such phases and M2 boride phase, Para[0020]. The R-Carbide taught in Kamata corresponds to the R-M2-C phase of claim 8. Kamata teaches a concentration of 0.1 to 3.0 atom% M1 overall, Para[0028], and a concentration of M1 in the grain boundary phase of 2 to 8 atom%, Para[0036]. One of ordinary skill in the art could select an amount of M1 in the grain boundary phase that is greater than the overall concentration of M1. In instances where the concentration of M1 in the grain boundary phase is higher than the overall concentration of M-1, the concentration of M1 in the grain boundary phase must be greater than the concentration of M1 in the main phase. As stated above, M1 of Kamata corresponds to M1 and M2 of claim 8. Therefore, Kamata reads on all limitations of claim 8.
Claim 9 further limits claim 1 by stating that the magnet has an average grain size D50 of 1.2 to 4.0 µm, calculated as the area average of equivalent circle diameters of main phase grains in a cross section parallel to the orientation direction of the R-T-B sintered magnet.
Kamata teaches that the magnet has an average crystal grain size of up to 6 µm, preferably 1.5 to 5.5 µm, Para[0043]. This overlaps with the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exist, see MPEP 2144.05. Kamata also teaches that the cross-sectional area of individual grains is determined, from which the diameter of an equivalent circle is computed, Para[0043]. Therefore, Kamata reads on all limitations of claim 9.
Response to Arguments
Applicant's arguments filed 15 April 2026 have been fully considered but they are not persuasive. Applicant argues that (remarks, page 6 of 7) Kamata does not cover the limitation requiring no boride phase because the boride phase is an essential component of Kamata. This is not found persuasive because although Kamata does teach a boride phase, Kamata teaches that at the grain boundary triple junction, there are formed an R oxide phase, R carbide phase, R nitride phase, or R oxyfluoride phase of high-melting compound or a mixture of such phases and M2 boride phase, Para[0020]. This means that the boride phase is optional and may be replaced by one of the other phases, including the carbide phase as in the claimed invention, without a critical change in properties. Additionally, as stated in the 103 rejection above, Kamata discloses the composition and method that does not appear to be patentably distinct from that of the claimed invention. Thus, all physical properties of the claimed invention, including the microstructural phases of the magnet, are inherently present in Kamata. The rejection is maintained.
Conclusion
THIS ACTION IS MADE FINAL. 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.
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/JACOB BENJAMIN STILES/Examiner, Art Unit 1733
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