Summary for gold plating brass pins Discussion
Gold plating brass pins for high-temp soldering is discussed as a way to improve solderability for HMP solder assemblies. Mike McMonagle asked whether a nickel underplate is necessary and what problems might occur without it. Dr. Lev Gorker recommended using nickel as an underlayer before gold plating, noting that a non-bright nickel from a sulfamic electrolyte or electroless nickel from an acetic solution is suitable; he also explained that after gold plating and HMP soldering, the nickel will not have micropressing centers. Mike then asked about thicknesses, and Vijay Deval advised that gold on dull nickel should not exceed 0.3 microns, warning that heavier gold can make soldered joints brittle. The thread therefore favors a nickel underplate and very thin gold for this application, with the main concern being joint brittleness if gold is too thick.
Q. We use brass pins and eyelets in our assemblies that are soldered with HMP solder, we are looking to pre-plate the parts with gold to improve solderability. Is a nickel underplate required or can it be skipped for a simple application such as this? What are the pros and cons, and potential problems without the nickel?
Mike McMonagle
– Houston, Texas
Dear Mike,
You can use electroplated nickel without brightness additives, for example from sulfamic electrolyte. Because you make after gold plating and HMP soldering the nickel coating will not nave micropressing centers. Nickel coating from Sulfamic electrolyte or electroless nickel coating from acetic solution are recommended as underlayer before gold electroplating for this causes.
Dr. Lev Gorker
– Israel
Dr. Gorker,
Thanks for your response, it is what I had suspected based on my previous work with gold plated printed circuit boards requiring electroless nickel before immersion gold. What would be the recommended thicknesses of the nickel and gold for this application? Thanks again for your assistance.
Mike McMonagle
– Houston, Texas
Gold plating on dull Nickel should NOT EXCEED 0.3 microns. Heavier gold thickness can cause brittle soldered joints.
Vijay Deval
– Maharashtra, India