Abstract: | Ferrites and chromites of Ni and Co synthesised by solid reaction method are usually used as black colour ceramic pigments. Due to the presence of Co and Ni in their composition they are classified as harmful substances. In this work, Co, Cr and Fe have been partially substituted by harmless Mg and Al ions, and the optimised compositions have also been synthesised by coprecipitation and gel polymeric route. Samples obtained have been characterised by CIEL*a*b colour parameters, XRD, DTA-TG, and SEM-EDAX techniques. Samples obtained by gel polymeric route presents the best reactivity and black colouring results. |