DETAILED ACTION
REJECTIONS
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim Rejections - 35 USC § 103
Claims 1-2, 5-9 and 11-19 are rejected under 35 U.S.C. 103 as being unpatentable over Takashi et al. (CN 113518674) in view of Watanabe et al. (U.S. App. Pub. No. 2013/0181802).
Regarding claim 1, Takashi et al. discloses a soft magnetic powder comprising 89.5 to 99.6 mass% Fe (Abstract). The soft magnetic powder has a D50 particle diameter of 2.3 micrometers or less, which overlaps with the presently claimed range. (page 3, [5]). As set forth in MPEP 2144.05, in the case where the claimed range “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).
Takashi et al. discloses that the surface of the magnetic powder is coated with an insulated organic or inorganic binder, including silica or alumina. (i.e. an insulating covering oxide, page 8, last 2 paragraphs).
With respect to the contents of O, C and N, Takashi et al. discloses that the oxygen content is in the range of 0.1 to 1.5 mass% (page 5, 2nd to last paragraph), the nitrogen content is in the range of 800 ppm or less (i.e. 0.08% or less) and a carbon content of less than 1 mass%. (page 5, first full paragraph, tables on page 12).
Takashi et al. does not teach the overall O, C and N content including the insulating layer.
Watanabe et al. teaches a soft magnetic powder for use as a dust core that includes an insulating layer comprising Si, O and at least one alkali metal as a layer on the surface of an iron based magnetic core material. (Abstract). The insulating layer has an O content of 20-70% by mass (par. [0049]) with a mass ratio relative to the core of 0.1 to 1.0% which affects the overall thickness of the layer. (par. [0050]). Watanabe et al. teaches that this mass ratio allows for sufficient insulation while ensuring that the coating isn’t excessively thick to allow enough magnetic particles are present in the dust core. (par. [0050]).
It would have been obvious to one of ordinary skill in the art to use an insulating layer content in the range disclosed in Watanabe et al. with the magnetic powders of Takahashi et al.
One of ordinary skill in the art would have found it obvious to use an insulation layer having mass ratio as disclosed in Watanabe et al. in order to provide sufficient insulation to the magnetic particles while ensuring that the coating isn’t excessively thick to allow enough magnetic particles are present in the dust core.
Since the mass ratio of the insulating layer is taught to be 1.0% by mass or lower, the content of O and other impurities such as C and N would be significantly below the claimed values for the total combination of these elements in combination with those present in the core as taught by Takahashi et al. For example, the content of O in the insulating layer in Watanabe et al. with respect to the overall magnetic particle ranges from 0.0002% (0.001 x 0.2) to 0.07% (0.01 x 0.7) which in combination with the O value of the magnetic particles would total 0.1001% to 1.52%. The contents of N and C in the insulating layer, while not explicitly disclosed, would not be substantially contained (i.e. less than 1%) in view of the teachings in par. [0049] of Watanabe et al. regarding the composition of insulating layer containing only Si, O and an alkali metal.
Regarding claim 2, the insulating layer is a glass material such as silica and alumina. (page 8, last paragraph).
Regarding claims 5 and 11, while Takahashi et al. does not explicitly disclose the D90 particle size of the magnetic particles, the D50 value substantially overlaps with the presently claimed range and therefore the D90 value would likewise be expected to substantially overlaps. Alternatively, "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." In re Aller, 220 F.2d 454, 456 (CCPA 1955). MPEP 2144.05 (II). One of ordinary skill in the art would have found it obvious to optimize the D90 particle size and the particle size distribution of the magnetic particles in general in order to improve the filling space between the magnetic particles to form a high density magnetic compacted material.
Regarding claim 6-9 and 12-15, Watanabe et al. teaches an insulating layer materials including Si, Ca, alkaline earth silicates and Fe. (par. [0049]).
Claims 2-3 are rejected under 35 U.S.C. 103 as being unpatentable over Takashi et al. (CN 113518674) in view of Watanabe et al. (U.S. App. Pub. No. 2013/0181802), further in view of Maeda et al. (U.S. App. Pub. No. 2012/0286191)
Takahashi in view of Watanabe et al. are relied upon as described in the rejection of claim 1, above.
Takahashi in view of Watanabe et al. does not explicitly disclose the compound used in the insulating layer being glass or crystalline.
Maeda et al. teaches a magnetic member including iron-based alloys powders which are provided with an insulating layer on the surface thereof. (Abstract, par. [0013], [0066] and Fig. 1). Maeda et al. teaches that the insulating layer may be glass compounds or crystalline films. (par. [0066]).
It would have been obvious to one of ordinary skill in the art to use an insulating layer including glass or crystalline materials as the insulating layer in Takahashi et al.
One of ordinary skill in the art would have found it obvious to use either glass or crystalline compounds in view of the teachings in Maeda et al. that such materials are known in the art to be suitable for providing an insulating film on the surface of magnetic particles. The selection of a known material based on its suitability for its intended purpose is prima facie obvious. MPEP 2144.07.
Claims 4 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Takashi et al. (CN 113518674) in view of Watanabe et al. (U.S. App. Pub. No. 2013/0181802), further in view of Ikari et al. (U.S. App. Pub. No. 2015/0104664).
Takashi in view of Watanabe et al. is relied upon as described in the rejection of claims 1 and 2, above.
Regarding claims 4 and 10, Takahashi et al. does not disclose a compact having a volume resistivity value as claimed under a pressure of 64 MPa.
Ikari et al. teaches a magnetic material made from a soft magnetic powder having a volume resistivity of not less than 1.0x101 Ω.cm. (Abstract and par. [0075]). Ikari et al. teaches that a higher volume resistivity results in reduced eddy current loss which therefore improves the quality of the magnetic core material. (par. [0096]).
It would have been obvious to one of ordinary skill in the art to optimize the volume resistivity of the compact made from the magnetic particles of Takahashi et al. in view of the teachings in Ikari et al.
One of ordinary skill in the art would have found it obvious to optimize the volume resistivity in order to reduce the eddy current loss to form an improved soft magnetic core having improved properties.
ANSWERS TO APPLICANT’S ARGUMENTS
Applicant’s arguments in the response filed 01/16/2026 regarding the prior art rejections made of record in the office action mailed on 08/19/2025 have been carefully considered but are deemed unpersuasive.
Applicant argues that Table 1 of Takashi et al. teaches a Fe content in the range of 92.0% to 92.5% by mass which lies outside the presently claimed range of 99 wt.% or more Applicant similarly argues that the disclosed D50 diameters as shown in Table 1 of the primary reference lie outside the presently claimed range. (Applicant’s response filed 01/16/2026, pages 7-9).
A prior art reference is prior art for all they contained and disclosed examples or preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments. (MPEP 2123 I-II). Takashi et al. discloses a Fe content and D50 particle size diameter which overlaps with the presently claimed range and therefore renders the claimed ranges obvious. (see rejection of claim 1 above). Although Takashi et al. in Table 1 teaches embodiments which lie outside of the presently claimed ranges, these do not negate the broader disclosure which does. Applicant’s argument relying on the specific embodiments in Table 1 therefore are not persuasive.
Applicant further argues that Watanabe et al. teaches using soft magnetic particles that are Fe-Si-Al based alloys which have Fe contents which would be outside the claimed range as well as having having average particle diameters in the range of 10-100 micrometers, which is outside the claimed D50 values. (Applicant’s arguments, page 10).
These arguments are not persuasive because the proposed combination as set forth in the claim rejections above teach all of the claimed features as set forth in both Takashi and Watanabe et al. Applicant’s arguments based on the content of Fe or size of the particles in the secondary reference therefore are not persuasive in relation to the rejection as set forth above which involves applying the insulating layer composition as taught in Watanabe et al. onto the particles of Takashi et al. Applicant has not persuasively argued why the size or Fe difference would not render the claims obvious over the cited prior art.
Applicant finally argues that the coating process according to Watanabe et al. exposes the particles to atmospheric oxygen which oxidizes the surface of the particles prior to coating. (Applicant’s arguments, page 11, relying on Watanabe et al. par. [0029]). However, par. [0029] does not disclose the presence of atmospheric oxygen or the oxidation of the particle surface. If Applicant’s argument is that the Fe content would necessarily lie outside the claimed range using the process disclosed in Watanabe et al., Applicant has not presented evidence to support such an argument. Arguments present by Applicant cannot take place of evidence in the record. MPEP 716.01(c). Therefore, the arguments are not persuasive and the claims remain unpatentable for the reasons set forth above.
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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/ALEXANDRE F FERRE/Primary Examiner, Art Unit 1788 03/17/2026