Ceramic Black Pigments Based on Chromium-Nickel Spinel NiCr 2 O 4

The possibility of obtaining black pigment based on nickel chromite (NiCr 2 O 4 ) is examined. The morphological, granulometric, x-ray structural, and optical characteristics of synthesized crystalline powders of chromium nickel spinel are investigated. Upon spontaneous crystallization at temperature 950°C nickel chromite crystallizes in the spinel structure Fd3m with crystals ranging in size from 1.29 to 84 μm (predominantly in the form of an octahedron). The diffuse reflection spectra showed high emissivity of NiCr 2 O 4 : the diffuse reflection coefficient ranges from 2.65 to 4.81% in the range 320 – 1080 nm. Black glazes based on nickel chromite were obtained; the optimal weight content of the pigment is 6 – 8%.