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Problem about bright surface coating by pvd

I am working as a engineer in a company which manufactures handles. we use cathodic arc PVD processes on the handles. but before PVD processes we are doing electroless coating .we coat nickel first.we use brass alloy for handles.my problem is we have some problems like uncoated part on the surface when we tried to coat TiN on the brass handle with nickel coated.some part was coated some part wasn't coated.we have this problem just bright nickel surface.could you help me please.what can you suggest me?

Burak Kosif
handles - Istanbul, Turkey
July 9, 2009

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Coating over nickel is a problem. The TiN won't adhere well if there is residue left over from the nickel bath, in which case it's a cleaning problem. It could also be associated with stress. The nickel is likely to have a residual tensile stress, and the TiN a residual compressive stress, hence you get a large problem at the interface. If it's due mostly to stress in the nickel plating, you should see more delamination on convex surfaces; if due to the coating, concave surfaces.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
July 20, 2009