SYNTHESIS AND CHARACTERIZATION OF SOME THERMORESISTANT PIGMENTS BASED ON THE Al3+ -> Cr3+ SUBSTITUTION

The paper presents the obtained results in the synthesis of some thermoresistant pink pigments with different structures, such as: corundum (Al2-xCrxO3), spinel (ZnAl2-xCrxO4, MgAl2-xCrxO4) and perovskite (LaAl1-xCrxO3). An unconventional synthesis method has been used in order to increase the substitution of Al3+ with Cr3+. The method used is based on the thermal decomposition of organic complex combinations containing as ligand the glyoxylate dianion, (C2H2O42-). The evolution of the crystalline phases with temperature has been investigated by XRD. The colorimetric characterization of the obtained pigments has been studied by diffuse reflectance spectrophotometry.