Claims
- 1. A method for forming a soldering alloy film on the surface of a circuit panel metal substrate for electronic parts, which comprises soaking the metal substrate or a non-metal support having the metal substrate disposed thereon in a solution of a soldering alloy salt in a high boiling point solvent, at a temperature of from about 230.degree. to 280.degree. C., characterized in that the soldering alloy salt is a salt of a soldering alloy, which is the soldering alloy to be formed on the surface of the metal substrate, and an acidic substance selected from the group consisting of an organic carboxylic acid having at least 4 carbon atoms, an acidic substance of natural origin containing abietic acid and d-pimaric acid and that which has been modified to contain 2 or 3 carboxyl groups, wherein the metal substrate is larger in ionization tendency than the soldering alloy to be formed on the surface of the metal substrate.
- 2. The method according to claim 1, wherein the soldering alloy to be formed on the surface of the metal substrate is comprised of at least two of the metals selected from the group consisting of zinc, cadmium, chromium, iron, nickel, cobalt, tin, lead, bismuth, copper, silver and gold.
- 3. The method according to claim 1, wherein the soldering alloy to be formed on the surface of the metal substrate is a mixture of tin and lead.
- 4. The method according to claim 1 wherein the metal of the metal substrate is selected from the group consisting of zinc, aluminum, iron, nickel and copper.
- 5. The method according to claim 14, wherein the metal of the metal substrate is copper.
- 6. The method according to claim 1, wherein the non-metal support is a glass or a resinous base.
- 7. The method according to claim 14, wherein the solvent is squalene and the soaking temperature is 250.degree. C.
- 8. The method according to claim 1 wherein the soaking time is from several seconds to several minutes.
- 9. The method according to claim 1, wherein the organic carboxylic acid having at least 4 carbon atoms is an aromatic mono-carboxylic acid or a di-carboxylic acid.
- 10. The method according to claim 1, wherein the organic carboxylic acid having at least 4 carbon atoms is a fatty acid.
- 11. The method according to claim 1, wherein the acidic substance of natural origin are rosins and derivatives thereof.
- 12. The method according to claim 11, wherein the rosin derivative is selected from the group consisting of a disproportioned rosin, a hydrogenated rosin, a gum rosin, a tall oil rosin, a wood rosin, a maleic acid-adduct of rosin and a fumaric acid-adduct of rosin.
- 13. The method according to claim 1, wherein the soldering alloy content in the solution is at least 0.1% by weight.
- 14. The method according to claim 1, wherein the high boiling point solvent is selected from the group consisting of squalene and high boiling point mineral spirits.
Priority Claims (2)
Number |
Date |
Country |
Kind |
61-114441 |
May 1986 |
JPX |
|
61-154811 |
Jun 1986 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 7/051,299 filed on May 19, 1987 now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
2813805 |
Kendall |
Nov 1957 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
51299 |
May 1987 |
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