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We increase magnetism of electroless nickel plating by baking, but oxide becomes a problem

I an new to the black art of plating/finishing and so apologise if my question appears naive.

EN plating (Low P) of microsized glass particles (NiCl2.6H2O, sod cit. 2H2O, NH4Cl, hypo, pH8 / 70° C) gives non-magnetic particles with about 400nm Ni coat. Subsequent heat treatment in a baffle furnace in air dramatically increases the magnetic properties of the composite material but is accompanied by an oxide layer (golden brown, higher temperatures gives blue layer) which suppresses electrical conductivity. Can anybody suggest a suitable acid treatment to remove the thick nickel oxide layer and replace it with an orderly thin layer that will enhance conductivity-and not remove too much of the nickel layer.

Malcolm Banks
Product Designer - Edinburgh United Kingdom
March 13, 2011

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March 16, 2011

Hi Malcolm,

Bi-fluoride base activator is more effective to remove nickel oxide. You may contact proprietary chemical supplier for such nickel activator.

Regards,
David

David Shiu
- Singapore

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Is it not possible to do heat treatment either in vacuum or inert atmosphere and avoid oxidation?

H.R. Prabhakara - Consultant
Bangalore Plasmatek - Bangalore Karnataka India
March 17, 2011