Spinel pigments in the ZnO-CoO-Al_2O_3-Cr_2O_3 system prepared from organometallic precursors

摘要

The synthesis of oxide compounds by thermaldecomposition of complex polynuclear combinations providessignificant improvements as compared with the traditional methods, particularly:- lower synthesis temperatures;- higher purity and fine grain.There have been obtained spinel pigments in the ZnO-CoO-Al_2O_3-Cr_2O_3 system by the thermal decomposition ofcertain complex heteropolynuclear compounds.The complex compounds have been isolated after the heatoxidation in aqueous solution of 1,2-ethanediol to the glyoxylatedianion by nitrates of zinc, cobalt, aluminium and chrome,according to the following redox reaction [1,2]:C_2H_4(OH)_2 + 2NO_3->C_2H_2O_4~2- + 2NO + 2H_2OThe aim of the paper is to study the behaviour of the complexcombinations during the thermal treatment in order to synthesisespinel pigments in the ZnO-CoO-Al_2)_3-Cr_2O_3 system aswell as the correlation between their composition and colour.