Synthesis, properties and applications of novel inorganic yellow pigments based on Ni-doped Al2TiO5

Single phase Al 2-2 x Ni x Ti 1+ x O 5 (0 ≤  x  ≤ 0.4) solid solutions were successfully synthesized by solid-phase reaction. The color of the compounds varied from yellow ( x  = 0.1) to turmeric ( x  = 0.4) with increasing nickel content. X-ray photoelectron spectroscopy analysis confirmed that the oxidation state of Ni is +2. The UV–Vis absorption spectrum showed that the color of the sample comes from the d-d transition of Ni 2+ in octahedral coordination. Owing to excellent high temperature stability, the as-prepared oxide powders (10 wt%) were mechanically mixing with Al 2 O 3 by conventional ball milling to prepare colored alumina ceramics. When Al 2 O 3 is in excess, the blue NiAl 2 O 4 impurity phase appeared, contributing to an intense green color of the Al 2 O 3 ceramics composite. The Vickers micro hardness value of green alumina was higher than that of pure white alumina. The as-prepared samples were also dispersed in PMMA and bright yellow polymer composites were obtained, indicating great potential in polymer colorant.