Where the
world gathers for metal finishing
Q&As since 1989


-----

Brown Stain on TiN coating after Salt Spray Testing

We are having problems with TiN coatings over chrome plated plastic failing in a 96 hour Salt Spray Test. The product out of the test chamber shows a brown staining on the PVD layer. A similar product PVD coated at a different facility passed the test.The noticeable visible difference between the two coatings before testing is a purple colour in deep recesses where chrome hasn't covered nickel on the product that passed testing. The failed product had a uniform colour over the complete product. Could this be a difference in the PVD layer i.e TiN or TiCN and would you expect one type to be better than the other? Has any one had similar experiences and any ideas as how to fix ?

Tim Strickland
General manager - Waitakere, Auckland, New Zealand
2003