Ceramic Black Pigments Based on Chromium-Nickel Spinel NiCr2O4

Resumo

The possibility of obtaining black pigment based on nickel chromite (NiCr₂O₄) 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 NiCr₂O₄: 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%.