Nodular Deposit in Hardchrome Plating

Q. Can I know the root cause for Nodular deposit in hardchrome plating? Please note that component is made by using heat treated highcarbon alloy steel material.

A. Dear Sir, nodules generally indicate a poor surface preparation or inadequate reverse etch. Base metal prep should include degreasing, polishing to meet a required micro and/or grit blasting using a suitable blast media (prefer aluminum oxide) Check anodes for good condition and conductivity. Verify racking and part connection is adequate to carry the necessary amps required. Allow sufficient time for a complete reverse etch especially for large parts and when anode to cathode spacing is excessive. A standard reverse etch for high strength, low alloy steels can be from 1-2 minutes depending on part size and anode configuration.

Randy Taylor