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Anhydrous nickel(2)chloride in nickel sulfamate bath

Does it make any difference if I add anhydrous nickel(2)chloride instead of hydrated nickel(2)chloride salt in a conventional nickel sulfamate bath? Shall I have to add a smaller amount if I add the first one? What is the chloride concentration for a given concentration of nickel(2)chloride?

SAID EMRE ALPER
MIDDLE EAST TECHNICAL UNIVERSITY - ANKARA, TURKEY
2003

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Anhydrous salts tend to absorb water, so you don't know their true composition. Consequently you cannot make precise additions of specific ions (i.e., nickel or chloride) as you don't know the true molecular weight. It is better to use the hydrated salt and work out your weights from the known compositions. However, technically, sulphamate nickel doesn't need chloride added if you use S-nickel rounds as the anode. Saying this, most sulphamate users tend to use about 10g/L nickel chloride (as the hydrate) to be on the safe side.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003