Metal finishing Q&As since 1989

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Cleaning Alloy42 for 60Sn/40Pb Solder Dipping

 

I'm trying to pretreat some electronic components (CerDIPs) to successfully solder dip the leads. The leads are made from Alloy42 and have a black oxidized appearance. I'm looking for a good chemical that can pretreat the leads before the solder dip process as well as any processing tips that will yield a good solder adhesion and wetting.

Michael Koelzer
- Austin, Texas

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Composition, % 42 Ni
P 0.025 max.
Al 0.15 max.
Fe Remainder
S 0.025 max.
Co 1.0 max.
C 0.05 max.
Si 0.30 max.
Mn 0.80 max.
Cr 0.25 max.
Anywhere from hot HF, hot 20% HCl, anodic etch in Wood's nickel strike, anodic/cathodic in 30% H2SO4, to get off the black oxides and leave you with a clean part.

  
Tom Pullizzi
Falls Township, Pennsylvania

I don't believe the HF or HCl can clean the Alloy 42. But I have one big concern. If this halide is not clean thoughtfully, it may lead to the oxidation of the alloy. In mass production, there is some imperfection in the clean process. Once, it happens, it may be a big trouble. Is it make-sense? Please advise.

Alan Ng
- Hong Kong
 

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The basic inorganic chemicals are used on this process called "Preclean". I experience with Sulfuric 50% with 50 °C and 10 min immersion condition then rinse, after that move to Bright dip solution which is about 20%Nitric and 25%Sulfuric Mixed under 20-25 C temp., 10-20 second immersion time. It's work but time is critical and I looking for improvement such as inhibitor. That 's all I can share.

Suphanai J.MMT
Millennium Microtech(Thailand) - Thailand