Nickel Plating Titanium(2001)
I am trying to determine if there is a better coating on titanium alloy for solderability. The titanium alloy was chosen to meet customer weight requirements and the nickel plating selected to make the titanium solderable.
We are currently Nickel Plating IAW SAE-AMS-QQ-N-290 [link by ed. to spec at TechStreet] , Class 1, Grade G on Titanium Ti-6-AL-4V ELI. We have experienced areas on the housing assembly that are not solderable. The mean value of the nickel plating is 274.32 micro-inch. SN63 Solder with 1544 Flux is used during the soldering process.
Could this be due to poor nickel plating adhesion to the titanium? Could this be due to the nickel plating thickness? Could this be due to the plating evaporating during the soldering process?Rob Sprong
electronics - Mason, Ohio, USA
First of two simultaneous responses -- (2001)
I'm not familiar with that flux callout but if its RMA flux you're going to have problems. I had a problem like this and I found out that the RMA flux is not active enough to get through the oxide layer. Try soldering immediately after plating and if it works good then this is the problem. You could then ask your plater to ship the parts in a sealed bag that was purged with nitrogen. Delamination of the nickel would appear like blisters, so if you didn't observe any I think its adherent. If that flux is Zinc Chloride or something similar then the nickel could dissolve away. Did the flux appear Green? If so your on the right track. you could do a nitric acid spot test to determine if the nickel is gone.
- Danbury, Connecticut, USA
Second of two simultaneous responses -- (2001)
Would it be possible to reduce the nickel plate thickness and have some tin plating on top which is far better to solder to?
surface treatment shop - Stroud, Glos, England
I would put two to five tenths of a mil of cyanide copper under the nickel.
Falls Township, Pennsylvania
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