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
Applicant’s election without traverse of species iii, claims 1-14, in the reply filed on 3/26/26 is acknowledged.
Note that Group 1, claim 10, was previously elected on 11/3/25. Additionally, since the closest disclosed example of an active brazing material, Ag-Cu28-2Ti, to species i, Ag75-Cu26.5-Ti3.0, has solidus temperature of 775°C, it is reasonable to conclude that species i does not have solidus temperature below 650°C. Thus, claim 5 is also withdrawn.
Claim Objections
Claim 2 is objected to because of the following informalities: in claim 2 “an intermediate” should be –the intermediate—and there should be an –and-- after “at least 25 seconds;”. Appropriate correction is required.
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.
Claims 1-4 and 6-10 are rejected under 35 U.S.C. 103 as being unpatentable over Applicant’s Admitted Prior art (AAPA) in view of vbcgroup “Active Braze Alloys and their Applications”, Makino et al. (JP 4-265281 A), and Morgan Advanced Metals “Ticusil”.
Regarding claim 1, AAPA teaches:
A process of connecting a silver-graphite [AgC] contact with a copper carrier, comprising:
brazing the silver-graphite contact to the copper carrier [the AgC contact is brazed to the Cu carrier with Cu-Ag-P braze; 0003].
AAPA does not teach:
coating the silver-graphite contact with a braze at a temperature of at least a solidus temperature of the braze minus 100 K,
wherein the braze contains one or more of Ti, Hf, Zr, Cr, Si and/or V and, further contains Cu in an amount of 24.0 wt.-% to 50.0 wt.% with respect to a total weight of the braze, with a remainder being one or several of Ag, In, Sn and/or Ni, thereby producing an intermediate, and thereafter, brazing the copper carrier onto the intermediate.
Concerning the use of an active braze:
vbcgroup teaches, “Active brazing is used when conventional brazing will not work. This is typically with ceramic materials such as alumina, silicon carbide, sapphire, diamond and graphite… It uses braze alloy in foil, paste, wire or preforms to join ceramic to ceramic or frequently ceramic to metal usually in a vacuum furnace… In the case of active braze alloys however a reaction takes place between the active element within the filler metal, usually titanium and the oxides, carbides or nitrides. This forms titanium oxide, titanium carbide or titanium nitride which allows the filler metal to wet the surface of the ceramic. Titanium is the most commonly used active element in commercially available braze alloys… There is an array of commercially available active braze alloys with brazing temperatures ranging from 700⁰C to over 1050⁰C. The compositions range from less than 1% active element (VBC Alloy 4081, Gold ABA) to 70%(VBC Alloy 4028, Ticuni), though 1%-4% is more typical.”
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to substitute the conventional braze of AAPA with an active braze, comprising Ti, in order to directly bond the AgC contact to the Cu carrier; note this is the main advantage of active brazes.
Concerning the coating with active braze:
Note that the coating/applying of a brazing/soldering material is known in the art as pretinning.
Makino teaches bonding ceramic sheet (13) to metal sheet (11) using Cu-Ag-Ti active brazing material (12), wherein the brazing material is coated onto the ceramic sheet by melting; 0007-0009.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to coat the contact and/or the carrier as taught by Makino because it is known to apply brazing material in this manner. One would have also been motivated to do so in order to speed up the assembly process, to ensure the proper amount and placement of brazing material, and/or to sell/provide the workpieces as ready for brazing.
Concerning the choice of active braze:
AAPA teaches Ticusil is a commercially available; 0038.
Vbcgroup teaches the majority of the brazing alloys are Ag and Cu based with Ti.
Makino teaches using Cu-Ag-Ti active brazing material (12), which has a melting point of ~780°C; 0007-0009.
Morgan teaches Ticusil allows ceramic-to-ceramic and ceramic-to-metal surfaces to be brazed without metallizing, firing and electroplating, cuts time and costs in manufacture of ceramic/metal assemblies, allows one step bonding to ceramics, can bond copper and graphite, and has a solidus temperature of 780°C.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use Ticusil for any of the reasons noted by Morgan, or due to cost, availability, and/or familiarity.
Regarding claim 2, AAPA does not teach:
wherein coating the silver-graphite contact with the braze thereby producing an intermediate is carried out under at least one of:
a temperature above the solidus temperature of the braze [this met by the incorporation of Ticusil coating which is applied by melting];
a temperature of less than 80 K above the solidus temperature of the braze;
in a low oxygen environment;
in reduced pressure environment;
in a protective atmosphere;
for a time of at least 25 seconds;
for a time less than one hour.
Regarding claim 3, AAPA does not teach:
whereby the brazing of the copper carrier onto the intermediate is performed under one or more: at a temperature of 500 °C to 1000 °C; and/or
over a time of up to 5 minutes above solidus.
However, Morgan teaches Ticusil has a liquidus of 900°C.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to braze anywhere between 900-1000°C since Ticusil melts in this range, minus any unexpected results.
Regarding claim 4, 9, and 10, AAPA does not teach:
wherein a total weight amount of Ti, Hf, Zr, Cr, Si and/or V is between 1.0 and 10.0 wt.-% with respect to a total weight of the braze;
wherein the braze is an Ag-Cu-Ti braze;
whereby the braze contains silver in an amount of 44.0 to 75.0 wt.-% with respect to the total weight of the braze; and/or
titanium in an amount of 1.0 to 10 wt.-% with respect to the total weight of the braze.
However, these claims are met by the incorporation of Ticusil.
Regarding claim 6, AAPA does not teach:
wherein coating the silver-graphite contact with the braze thereby producing an intermediate is carried out at a temperature of up to 950°C.
However, Morgan teaches Ticusil has a liquidus of 900°C.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to coat anywhere between 900-1000°C since Ticusil melts in this range, minus any unexpected results.
Regarding claim 7, AAPA does not teach:
wherein the braze for producing an intermediate is a braze powder, braze paste or a braze foil.
Morgan teaches Ticusil is available as foil, powder, and paste.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use Ticusil in any of these forms since it is available in these forms.
Regarding claim 8, AAPA does not teach:
wherein the intermediate is brazed to the copper carrier by inductive, resistive or furnace heating.
Makino teaches active brazing in a vacuum furnace; ~0009.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to vacuum braze the contact and carrier assembly since it is known to do so with an active braze.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure; see PTO 892.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CARLOS J GAMINO whose telephone number is (571)270-5826. The examiner can normally be reached M-F 9-6.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Walker can be reached at 5712723458. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/CARLOS J GAMINO/Examiner, Art Unit 1735
/KEITH WALKER/Supervisory Patent Examiner, Art Unit 1735
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