Nickle Oxide Black
A powerful and refractory colorant that produces greys, blues, and yellows. It is more concentrated than nickel carbonate and as little as .02% gives a noticeable tint. Normal additions are 2-5%. Typical grades are 75-77% nickel metal with trace elements (0.0001-0.01%) of cobalt, iron, copper, zinc, manganese, magnesium, calcium, sodium and sulfur and chloride volatiles. Particle sizes can be very fine, down to 5 microns (below 325 mesh). It can also soften and mute more intense colorants such as copper and cobalt. It is refractory and can raise the melting temperature of glazes if used in large amounts.