Question? I want to try some Nickel oxide or nickel carb as a colorant in my glaze. Does anyone know the pros and cons of using one instead of the other. I know that nickel carbonate is less expansive.
B Macdugal
Nickel carb has less nickel per pound, so while it is less expensive more nickel carb will be required than nickel oxide to get the same effect. You'll likely find that the same dollar amount is needed to get the same amount of nickel with either so the cost difference probably isn't meaningful. With cobalt, the carbonate disperses better in glazes and is less likely to cause spotting as the oxide can. I don't know if you'll see a similar effect with nickel.
deg
fyi: there are two nickel oxides and one nickel carbonate basic offered commercially: nickel-3 oxide: gray-black powder, Ni2O3, density 4.84 g/mL, on firing at 600 oC it changes to:
nickel-2 oxide: green powder, becoming yellowish on standing, density 6.6-6.8 g/mL, on firing at 400 oC it changes to nickel-3 oxide which reverts to nickel-2 oxide at 600 oC.
nickel carbonate basic: uncertain composition, probably NiCO3.2Ni[OH]2.4H2O comes closest to its formula. This comes as light green cystals or brown powder, density 2.6 g/mL. made by combining soda ash, Na2CO3, to a solution of of nickel-2 sulfate aka sulphate. this compound on firing above 600 oC becomes nickel-2 oxide.
ask your supplier to tell you the amount of Nickel (elemental form) in the material you buy. it is the only way you can compare the above compounds since their compositions are variable from time to time. also be aware that nickel-2 oxide may be toxic in some fired glazes because it can be solubilized by weak (dilute) acids ... vinegar, lemon juice, orange juice. so do not use it in a liner glaze without careful testing and analysis.
Tom Buck -- primary address. "alias" or secondary address. tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada). mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
Unless it is essential, I would strongly suggest that you avoid using nickel salts. These have been classified as confirmed human carcinogens. Their use in industry inside the European Union is, quite rightly, very tightly controlled.
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