Electroless Nickel Problem Solving and Related Applications
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Q: The AMS2404 spec allows for "slight" discoloration, whereas the AMS-C-26074 does not.
How do you define "slight?" ....AMS2404G 3.5 Quality Plating, as received by purchaser, shall be smooth, continuous, and uniform in appearance and shall be free from frosty areas, pinholes, blisters, and other imperfections detrimental to usage of the plate. Slight staining or discoloration is permissible. Class 2 plating may discolor from thermal treatment.
The staining would be caused by "water mark" or drying of EN on the part. This is common on larger, flat pieces. To avoid this, add 1% ammonia and water-wetter to your final hot DI rinse. This will eliminate the staining while increasing the resistance other post plate imperfections(fingerprints and such).
As far as why the specs state different staining between the two...many times the specs are written for different applications in different parts of the world. One area may have had an issue with staining which did not harm part performance.
Date asked: 31 December 2013
Q: We are coating 6061 parts with two coatings: one is electroless nickel with tin plating on top.
After plating, we have noticed that some areas have a coarse texture relative to areas with a smooth surface.
What could be the reason for that?
If the roughness is occurring after the tin plating, but not after the electroless nickel plating, I would be focusing my concentration on the tin bath itself. First, make sure the tin bath you are using is within spec and not contaminated. Second, check your rectifier to make sure it is operating properly.
Date asked: 11 November 2013
Q: I have a question about mid-phosphate electroless nickel: How many hours (salt spray test) are required to pass with 15 micron thickness? We are plating over aluminum 6061, and we require 48 hrs of salt spray test to pass. Note: Any white spots on the component will be rejected after salt spray test.
The standard for most mid-phos electroless nickel is 100hr salt spray protection with 1mil of thickness. Over 6061 aluminum, you should not see any white spots after testing. Note: not all electroless nickel's are created equal. Please contact me if you need information on a product that is guaranteed pass your 48 hour test (standard for the aerospace connector industry).
Date asked: 05 September 2013
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