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Metal finishing Q&As since 1989
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What is the pretreatment for NiP coating on Al sheet by electroless method?
2006
I am doing NiP coating on Al sheet(commercial grade). I pretreated the substrate in SnCl2 and in PdCl2 respectively. But I got the coating dark/and sometimes bright but with dark patches. Is there any post-treatment which I should do?
Dhananjay Kumar2006
To plate electroless nickel on aluminum requires a zincate preplate step (double zincate is better). No need for palladium or tin, that's for plastics.
Guillermo Marrufo2006
That and a alkaline pH EN strike will really reduce the problems.
James WattsNavarre, Florida
2006
I agree with Mr. Guillermo Marrufo. Double zincating is the recommended pretreatment for Al alloys before electroless plating.
![T.S.N. Sankara Narayanan](../portraits/sankara_narayanan.jpg)
T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )
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