Joining process

• US 3,900,151 A
• Filed: 12/04/1973
• Issued: 08/19/1975
• Est. Priority Date: 09/02/1971
• Status: Expired due to Term

• Current Assignee: Heinz Schoer, Werner Schultze
• Original Assignee: Heinz Schoer, Werner Schultze
• Inventors: Schoer, Heinz, Schultze, Werner
• Primary Examiner(s): Shore, Ronald J.
• Application Number:
  US05/421,655
• Time in Patent Office: 623 Days
• Field of Search: 75/178A,178R,175A,175R,175AC,175AT,175AM,175AN,178A 29/494,504
• US Class Current: 228/220
• CPC Class Codes: B23K 35/282 Zn as the principal constituent

Abstract

A process for the fluxless soldering of aluminumcontaining workpieces in substantially non-oxidizing atmospheres is carried out with a solder which contains 2-26% by weight of Al and at least one additive from the group consisting of Bi, Sr, Ba, Sb and Be, the balance being Zn. The additives Bi, Sr, Ba and Sb constitute 0.01-10 percent by weight and the additive Be constitutes 0.00001-1.0 percent by weight of the solder. These additives lower the viscosity and surface tension of the molten solder and also decrease the interfacial tension between the molten solder and the workpieces.

Claims

1. IN A PROCESS OF SOLDERING ALUMINUM-CONTAINING WORKS PIECES, THE STEP OF SOLDERING SAID WORKPIECES WITH A ZN BASE SOLDER COMPRISING 2-26% BY WEIGHT OF AL, AND BE, AS A WETTING AGENT, SAID BE LOWERING THE VISCOSITY AND SURFACE TENSION OF SAID SOLDIER IN IRS MOLTEN STATE AND SUBSTANTIALLY DECREASING THE INTERFACIAL TENSION BETWEEN THE MOLTEN SOLDIER AND SAID WORKPIECES, AND SAID STEP BEING PERFORMED WITHOUT A FLUX AND A SUBSTANTIALLY NON-OXIDIZUNG ATMOSPHERE

2. In a process as defined in claim 1, wherein said solder comprises 0.00001-1.0 percent by weight of said Be.

3. In a process as defined in claim 2, wherein said solder comprises 0.002-0.1 percent by weight of said Be.

4. In a process as defined in claim 1, wherein said solder further comprises at least one substance selected from the group consisting of Bi, Sr, Ba and Sb as an additional wetting agent, said Bi, Sr, Ba and Sb lowering the viscosity and surface tension of said solder in its molten state and substantially decreasing the interfacial tension between the molten solder and said workpieces.

5. In a process as defined in claim 4, wherein said solder comprises 0.01-10 percent by weight of said substance.

6. In a process as defined in claim 5, wherein said solder comprises 0.05-2 percent by weight of said substance.

7. In a process as defined in claim 4, wherein said solder comprises 0.00001-1.0 percent by weight of said Be.

8. In a process as defined in claim 7, wherein said solder comprises 0.002-0.1 percent by weight of said Be.