CATALYTIC SENSITIZATION OF SUBSTRATES FOR METALLIZATION

• US 3,798,050 A
• Filed: 05/28/1971
• Issued: 03/19/1974
• Est. Priority Date: 05/28/1971
• Status: Expired due to Term

• Current Assignee: Helmut Franz, Roy G. Crissman
• Original Assignee: Helmut Franz, Roy G. Crissman
• Inventors: Franz, Helmut, Crissman, Roy G.
• Primary Examiner(s): Martin, William D.
• Assistant Examiner(s): Trenor, William R.
• Application Number:
  US05/147,790
• Time in Patent Office: 1,026 Days
• Field of Search: 117/47A,16R,13E,54 106/1
• US Class Current: 427/304
• CPC Class Codes: C23C 18/30 Activating or accelerating or sensitising with palladium or other noble metal

Abstract

Metal films of improved uniformity are formed on substrates having their surfaces sensitized by the deposition of palladium on tin by buffering the palladium salt solution in contact with the glass at a pH from 6 to 9. Buffering is preferably accomplished by contacting the substrate with an aqueous buffering solution and an acidic palladium salt solution.

Claims

2. In the method of coating a non-conductive substrate surface with a metal-containing deposit comprising the steps of:

first, contacting the substrate with a solution of tin salt and then rinsing the same;

second, contacting the substrate with a solution of palladium salt and thereafter contacting the substrate with a solution containing the desired metal to be deposited and reducing agent for such metal, whereby a non-uniform metal-containing deposit is formed, the improvement comprising the steps of;

rinsing the tin salt contacted substrate with a rinse of water containing an alkaline buffering compound in an effective amount to provide a pH of about 7 to about 9 in the mixture of palladium salt solution and remaining rinse in contact with the substrate whereby a uniform metal-containing deposit results.

3. The method of claim 2 wherein the contacting solutions are sprayed against the substrate.

4. The method of claim 2 wherein the alkaline buffer is selected from the group consisting of ammonium hydroxide, ammonium borate and water-soluble ammonium, alkali metal and alkaline earth metal carbonates, bicarbonates and phosphates and mixtures thereof.

5. The method of claim 4 wherein the rinse contains as an esential ingredient from about 0.01 to about 7 percent by weight of the aqueous rinse, sodium bicarbonate.