Failure testing of nickel plating
I would like to test the integrity of a nickel plating (IAW Mil-C-26074 [linked by editor to free spec at Defense Logistics Agency, dla.mil]E CLASS 2, .0015 MIN THICKNESS) on a part. Please tell me what the MOST harmful environment is for the plating. I need to know what will cause the plating to flake off, wear down, or be destroyed in some other way.Vince Vendetti
Naval Surface Warfare Center - Dahlgren VA
Flaking off occurs as the result of poor adhesion from improper surface preparation; this is probably best tested with a thermal stress cycle, most importantly, just heating the item to a substantial temperature. Wear can be tested with a Taber Abrasion tester.
Ted Mooney, P.E.
Pine Beach, New Jersey
Ted's suggestions are sound- and since MIL-C-26074 has been discontinued and the suggested replacement (AMS2404 [link by ed. to spec at TechStreet]) is really intended for the automotive industry and is less demanding in terms of physical requirements, you must choose your testing based on the intended service conditions. We employ a bend test of coupons using a 1/2" mandril. Also, since our parts are subsequently soldered in a vapor phase, we subject the parts (100%) to a vapor phase test (the thermal shock Ted mentioned) to check for blistering. In lieu of Taber abrasion resistance, you could also consider a microhardness test. For corrosive environments, think about CASS or salt spray testing as well.
avionics - Minneapolis, Minnesota
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