Synthesis of CoCuMnOx Pigments for Solar Collectors Absorbent Enamels

Abstract

This aim of this research is to produce Co, Cu and Mn mixed oxides by means of one-step solution novel combustion methods using aspartic acid, lysine or ethylenediaminetetraacetic acid as fuels. The pigments were characterized using x-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy with Fourier transform, Brunauer–Emmett–Teller techniques and the crystal structures refined by the Rietveld method. Finally, an enamel of alkyd- resin base was prepared with the pigment obtained and applied on an aluminum substrate (coating). In this coating, the solar spectral absorbance was determined. The obtained powders showed a CoCuMnO4 composition with spinel structure. An extraordinary value of absorption on the coatings between 95 and 97% was noted. The temperature achieved by coating to the sun was higher than that obtained for commercial black coating. These results suggest the possibility of utilizing these oxides in absorbent solar enamels.