Why is nickel plated under gold?
Nickel acts as a barrier layer. It keeps base metals such as copper from diffusing into the gold, and it adds hardness, which improves wear resistance and extends the life of the finish.
What specifications govern gold plating?
Common specifications include MIL-DTL-45204 and ASTM B488. They define purity, hardness, and thickness classes for engineering gold plating. Your drawing will call out the required type, grade, and class.
Is gold plating better than silver plating?
Each has its strengths. Silver offers higher conductivity at a lower cost. Gold offers superior resistance to corrosion and tarnish, which makes it the better choice for harsh environments and low-force signal contacts.
Which parts require hydrogen embrittlement relief?
High-strength steels are the most susceptible. Specifications typically require baking for steel parts above a defined hardness or tensile strength threshold. Your drawing or governing specification will state whether relief is required.
How soon after plating must parts be baked?
As soon as practical, and always within the window the specification sets. The longer hydrogen remains in the part, the harder it is to remove, and any cracking that begins before the bake cannot be reversed.