Síntese do pigmento CoCr2O4 pelo método de gelatina comercial

Abstract

There is a growing interest of the ceramic industries in developing more stable pigments that are low cost and little environmental damage. The ceramic industries mainly use pigments of predominantly inorganic nature, such pigments are the most used because they havean excellent chemical and thermal stability besides a lower toxicity to the man and few environmental damages. The most commonly used inorganic pigments used in ceramics are mixed oxides with spinel structure and AB2O4. Spinels are one of the most interesting crystalline structures in the development of stable and chemically inert pigments. In this structure, ions of different oxidation states are present in both tetrahedral and octahedral sites. In addition, there are several ways of arranging the cationsat these sites (normal and inverse spinel). These characteristics led to the development of different colors, being these intense and stable, suitable for use as pigments. Among the compounds used as ceramic pigments, we have highlighted CoCr2O4which is a mineral oxide belonging to the group of spinel, such structures cover a group of well-establishedmagnetic materials that may have a green coloration. The objective of the present work was to synthesize the CoCr2O4pigment using commercial gelatin as precursor and to characterize the following techniques: Thermogravimetric analysis (TG), Xray diffraction (XRD), surface area (BET), Scanning electron microscopy (SEM) spectroscopy in the infrared region (FTIR), and colorimetric measurements by the CIEL*a*b*method. The route of synthesis used was confirmed viable from the results. Crystalline, monophasic and high surface area compounds were obtained. The powders presented green coloration with phase obtained from 500 ºC.