Synthesis of CoAl2O4 by double decomposition reaction between LiAlO2 and molten KCoCl3

Submicronic CoAl2O4 powders were prepared by double decomposition reaction between solid LiAlO2 and molten KCoCl3 at 500 °C for 24 h. The reaction mechanism involves the dissolution of LiAlO2 shifted by the precipitation of CoAl2O4 until complete transformation and the reaction leads to powders with a very homogeneous chemical composition. The powders obtained were mainly characterized by XRD, FTIR, ICP, X.EDS, electron microscopy and diffraction and diffuse reflexion. The blue pigments obtained exhibit a high thermic stability allowing their use for the colouring of ceramic tiles.