Q. We plate components for one of our best customers in a nickel sulfamate plating bath. We use a small amount of brightener and grain refiner in the bath. Our customer thinks that the solder failures are due to the additives present in the bath. Is there any relationship between the amount of brightener and grain refiner in a nickel sulfamate bath and solder failure? Can we run the nickel sulfamate bath without a brightener and grain refiner?
We plate a copper substrate with 100 micro inches of nickel. S.L.
A. This question has been asked before. Why do you run the sulfamate bath with additives? Sulfamate nickel is usually called out when nickel plate without additives is required. Although solderability is not affected by the addition of small amounts of additives, additives are usually unnecessary in the sulfamate bath.
The most important factor is the oxidation of the nickel surface. The longer the delay between the plating step and the soldering step, the more likely you’re going to have solder failure. This is because the longer the nickel surface is exposed to oxygen in the atmosphere, the more the nickel surface will oxidize.
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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.