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Ask the Expert Question-and-Answer Archive
(Hard Chrome Plating)
by Randy Taylor, Advanced Tooling Corporation.
December, 2008
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
