Abstract A thick, solderable metallic coating is provided on a ceramic member by applying a metallic composition comprised of at least 10 weight percent, preferably at least 30 weight percent, of powdered molybdenum trioxide, or tungsten trioxide, or mixtures thereof, and at least 30 weight percent of powdered gold, or copper, or silver, or alloys thereof, on the surface of the member and then firing the coated member in a wet reducing atmosphere at a temperature above the melting point of the solderable material to substantially reduce the molybdenum trioxide and/or tungsten trioxide to the metallic form. In one embodiment, the molybdenum trioxide and/or tungsten trioxide is applied to the surface of the ceramic member first and gold, copper, silver, or alloys thereof, is then applied over this first coating. In another embodiment, the metallic composition is applied to the ceramic member as an admixture.
The method according to claim 1 wherein both said refractory metal oxide and said solderable material are suspended in a volatile vehicle and said coated member is dried after each coating step.
Claim 2
Dependent Claim
14 words
The method according to claim 2 wherein said refractory metal oxide is molybdenum trioxide.
Claim 3
Dependent Claim
41 words
The method according to claim 2 wherein said refractory metal oxide is an admixture of molybdenum trioxide and tungsten trioxide comprised of about 10 to about 40 weight percent molybdenum trioxide and about 60 to about 90 weight percent tungsten trioxide.
Claim 4
Dependent Claim
12 words
The method according to claim 3 wherein said solderable material is gold.
Claim 5
Dependent Claim
12 words
The method according to claim 4 wherein said solderable material is gold.
Claim 6
Independent Claim
135 words
A method for forming a solderable gold coating arranged in a predetermined pattern on the surface of a ceramic member comprising applying to said surface a first coating consisting essentially of a powdered refractory metal oxide selected from the group consisting of molybdenum trioxide, tungsten trioxide and mixtures thereof, in a volatile liquid vehicle in said predetermined pattern; drying the thus coated member; applying over said first coating a second coating consisting essentially of powdered gold in a volatile liquid vehicle; drying the thus doubled-coated ceramic member; and heating said double-coated member in a wet reducing atmosphere to a temperature at least as high as the melting point of said gold to substantially reduce said refractory metal oxide to metallic form and form a tightly adhering solderable gold coating substantially conforming to said predetermined pattern.
Claim 7
Dependent Claim
14 words
The method according to claim 7 wherein said refractory metal oxide is molybdenum trioxide.
Claim 8
Dependent Claim
41 words
The method according to claim 7 wherein said refractory metal oxide is an admixture of molybdenum trioxide and tungsten trioxide comprised of about 10 to about 40 weight percent molybdenum trioxide and about 60 to about 90 weight percent tungsten trioxide.
Claim 9
Dependent Claim
20 words
The method according to claim 7 wherein said coated member is maintained at said temperature for 1 to 30 minutes.
Claim 10
Dependent Claim
20 words
The method according to claim 8 wherein said coated member is heated to about 2,000* F. for about 5 minutes.