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How to solder on a nickel plating surface

Our company have some resistance must be soldering to a nickel plating surface.
but when the soldering tin melt down ,it can not firmly connect with the nickel plating surface, how can we deal with it ? what kind of activator can we use?

Wanliang Dai
- Nanjing, CHINA
2006

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2006

Baker's fluid is a suitable flux.
20%w/v zinc chloride
5%w/v ammonium chloride
5%v/v hydrochloric acid
0.01%w/v o cresol red ⇦ this on eBay or Amazon [affil links] or other dye
sodium lauryl sulphate or other wetting agent
The last two components are optional.
When you solder the acid fumes may damage the rest of the component. You can wash the remains of the acid and zinc off in a dilute (~10%) solution of triethanolamine and then water. The triethanolamine neutralises the acid and dissolves any zinc oxide ⇦ this on eBay or Amazon [affil links] which water would not.
Alternatively you could consider applying an immersion gold coating immediately after nickel plating. Although only 0.1 micron thick the gold preserves the nickel surface for several months. When you solder the gold dissolves and the solder should stick to the nickel without the need for a flux.

Nick Clatworthy
- Whitstable, Kent, UK