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Plating EN and bright Nickel on Mg

Does anyone know why I am getting blistering on the bright Nickel plating process after the EN plating? The EN plating looks fine on MG.

Tomy Brosius
San Jose, California
1999

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My guess is you are not successful in activating the EN. EN passivates or oxidizes rapidly and most nickels are much harder to activate than say steel. They also do not lend themselves to a visual inspection for activation unless the etch is excessive which creates other problems. A one minute transition from the EN to the bright nickel will give poor adhesion.

You may have to put a Woods nickel strike on the EN to get the bright nickel to adhere.

James Watts
- Navarre, Florida
1999

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The EN is probably passive before you go into the bright nickel. I would not recommend a woods nickel strike because the low pH and high chloride would dissolve the Mg very fast, even with the EN on the part and any microporosity in the coating would increase the dissolution of the Mg. A slightly acid dip before nickel plating, 1-3% sulfuric acid without a rinse should help.

George Shahin
Atotech - Rock Hill, South Carolina
1999