Q. A customer claims that brightener and grain refiner concentrations in a plating bath will affect the solderability of the plated surface. In our case, we are talking about nickel deposited from a nickel sulfamate bath. W.N.
A. The most important factor concerning solderability of nickel is oxidation of the nickel surface. Nickel surfaces oxidize (passivate) fairly readily. The amount of oxidation increases the longer the delay between the nickel plating step and the soldering process. The greater the amount of oxidation, the more difficult to solder.
If you have your brightener and grain refiner under control, there shouldn’t be any affect on solderability. However, there is no reason why a nickel sulfamate has to be run with organic additives unless a bright appearance is required. Other factors may also be at play here. Rinsing methods, handling and storage methods, and even weather conditions can affect the solderability of the nickel plate.