Green nanoceramic pigments based on cobalt chromite doped with Al: Synthesis, characterisation and colour performance

Nano-sized spinel cobalt chromite oxide CoCr2O4 and its substituted forms CoCr2−xAlxO4 (0 ≤ x 2) have been successfully synthesised by wet chemical route. The prepared powders were characterised means of thermal analysis (DTA/TGA), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET), UV–visible techniques (UV–Vis) colorimetric analyses (L* a* b*). results show that the samples are in crystalline phase at 900 °C with a particle size range 20–200 nm. colouration pigments is sensitive to distribution doping trivalent ions lattice. Al-enrichment leads colour shift from green blue grains become more spherical less agglomerated. Green 50% aluminium (CoCrAlO4), allowing specific surface area nanometric be increased 7.4 12.4 m2/g.