Powder Coating Adhesion on Stainless Steel

Article From: Products Finishing, , from Powder Coating Consultants, Div. of Ninan, Inc.

Posted on: 8/1/2001

Question: I am experiencing loss of adhesion in the field with powder coating over 304 stainless steel.

Question:

I am experiencing loss of adhesion in the field with powder coating over 304 stainless steel. The adhesion is terrific after it is painted. After the product is mounted to a truck and driven through snow, salt and sand, the non-stainless steel components begin to rust as expected. Unexpectedly though, is the loss of powder coat adhesion around the stainless steel components attached to the non-stainless steel parts. On these areas the paint comes off in chunks, and on the bare stainless steel surface there appears to be a white residue creeping under the paint from the non-stainless steel parts. We process our parts through a five-stage washer using iron phosphate and a non-chrome rinse. Why is the powder coating coming off the stainless steel parts? T.R.

Answer:

I suspect that the non-stainless steel parts and the stainless steel parts create a galvanic reaction due to the dissimilar metals. This causes the non-stainless steel parts to corrode at a faster rate and causes under-film corrosion on the stainless steel. Replacing the non-stainless steel components with similar stainless steel components should correct the problem.

Comments are reviewed by moderators before they appear to ensure they meet Products Finishing’s submission guidelines.
blog comments powered by Disqus


Learn More

Zones

Supplier Categories


Finishing Solutions
Therma-Tron-X
SIDSP
Magic Rack
Performance and Service

Suppliers | Products | Experts | News | Articles | Calendar | Process Zones

The Voice of the Finishing Industry Since 1936 Copyright © Gardner Business Media, Inc. 2014

Subscribe | Advertise | Contact Us | All Rights Reserved