Summary for satin coat alternative Discussion
Satin coat alternative is the core issue in this thread: Denys needs a RoHS-compliant finish for cold rolled steel electronic enclosures that can be powder coated, remain conductive on masked ground areas, and provide at least light corrosion protection without using zinc electroplating because of prior whiskering problems. He reports rust on masked areas with iron phosphate and says zinc nickel or zinc phosphate base coats may not be readily available in Western Canada. The only answer in the excerpt comes from an unnamed respondent who suggests nickel plating, possibly with a trivalent chromium top layer, as a possible alternative. No one in the excerpt confirms performance, availability, or whether it fully meets all of Denys’s requirements, so the discussion remains a tentative suggestion rather than a settled solution.
Q. I am working on a cold rolled steel, powder coated part that is used as an enclosure for a piece of electronic equipment.
The part used to be satin coat steel. Some spots on the part are masked prior to powder coating to provide a conductive electrical ground path.
Since the part is used in electronic equipment, the finishing needs to be RoHS compliant to be sold in the EU. We are no longer able to get RoHS compliant satin coat steel, and are looking at alternative finishes. Furthermore, we cannot use zinc electroplating as we’ve experienced significant issues with zinc whiskering in the past.
We’ve tried iron phosphate, but our current supplier is giving us a large percentage of parts with rust present on the masked areas. It is not clear whether this is due to inherent lack of corrosion protection of iron phosphate or has something to do with the finisher’s process.
We’re currently looking at using zinc nickel plating or zinc phosphate base coat instead, but both seem to not be available in Western Canada, so it might be more cost-effective to find an alternate solution.
In summary, I need a finishing process for cold rolled steel that:
– provides at least light corrosion protection
– acts well as a base coat for powder coating
– is conductive
– is RoHS compliant
– is not zinc electroplating
Any input would be greatly appreciated!
Denys [surname deleted for privacy by Editor]
– British Columbia, Canada
A. Why not nickel plating, maybe with a trivalent chromium top layer?
Jim Treglio – scwineryreview.com
PVD Consultant & Wine Lover
San Diego, California
January 6, 2015