Summary for solder nickel without flux Discussion
Nickel soldering without flux is the central issue in this thread. Jane He RNT says she has tried to prewet nickel with several solders, including Pb-Sn, Ag-Sn, and indium-based alloys, but none wet the nickel well without flux. The reply from an unnamed answerer is blunt: there probably is no solder choice that will reliably solve the problem on bare nickel. The reason given is that nickel quickly forms an oxide layer in air, and that oxide must be removed before the surface will wet. In other words, the discussion points away from finding a special solder and toward the need for flux or another oxide-removal method if soldering nickel is required.
Q. I have tried to prewet Nickel surface with many kinds of solder including Pb-Sn, Ag-Sn, Indium, Indium…none of them wet the Nickel very well without flux. Anybody knows what kind of solder will be a good choice for soldering Nickel.
Thanks a lot!
Jane He
RNT – Hunt Valley, Maryland
2005
A. I hate to be the bearer of bad news, but I don’t think you are going to have any success soldering nickel surfaces without flux. Nickel forms an oxide coating in air all by itself fairly rapidly, and unless you remove the oxide, the surface ain’t gonna wet.
James Totter, CEF
– Tallahassee, Florida
Q. Thank you for the reply.
So, if I clean the oxidation right before the joining, you think it will work?
Do you have any suggestions on the nickel oxidation cleaning?
Thanks again!
Jane He
– Hunt Valley, Maryland
A. Do not use a bright nickel or one that contains organics. this makes the surface even more resistant to post treatments. I would suggest a simple, basic, dull Watts nickel followed by whatever is suggested for getting solder to stick to nickel without flux.
Trevor Crichton
– UK
A. It is possible to solder to Ni without liquid or powder flux. Our company routinely solders to Ni using a belt furnace with a forming gas cover. The forming gas acts as a flux (i.e. cleaner) for the parts while they are being heated to the solder liquidus. When finished, the parts come out cleaner than when they went in.
Jim Petri
– Melbourne, Florida, USA