45040

White wash deposit after chrome plating [California] 

May 6, 2007

What causes white wash deposit on wheels after chrome plating aside from low ratio of Chromic acid to Sulfate concentrations in Chrome solution?

Thank you.

Louie Rumbaugh
Lab Supervisor - Carson, California

Ed. note: Send a good photo to mooney@finishing.com if you can, Louis. Maybe what you are calling 'white wash' someone else might call haze (or maybe not).

If by deposit you mean a salt layer, will it wash off with DI water? If it is and it has been baked on, it may take a very dilute acid to get it off.
My guess is that it is a haze or milky plate which can also be caused by the amperage either too high or too low for the tank temperature; or another catalyst that you might be using being too low.

James Watts
- FL

Might we not be looking at a passive nickel problem, requiring cathodic activation in acid or cyanide prior to chrome plating.

Geoff Whitelaw
- Port Melbourne, Vic., Australia

Try two simple fixes first -

1. Improve rinsing after nickel.

2. Let the part come to temperature for a short time after immersion in the chrome solution before applying current.

Jeffrey Holmes, CEF - Spartanburg, SC, USA