Combustion syntheses of CoAl2O4 powders using different fuels

MARÍA CELESTE GARDEY MERINO; ALFREDO L. ESTRELLA; MARIANA E. RODRIGUEZ; LEANDRO ACUÑA; MARÍA SILVINA LASSA; GUSTAVO E. LASCALEA; PATRICIA VÁZQUEZ

Procedia Materials Science

Elsevier

Lugar: Amsterdam; Año: 2015 vol. 8 p. 519 - 525

2211 8128

This research intends to analyse the potential use of CoAl2O4 as an opaque pigment for solar collector selective paints. The opacity of the pigment occurs when the average crystallite size is micrometric. The CoAl2O4 samples were synthesized through combustion methods using aspartic acid (Asp) or lysine (Lys) as fuels. The powders obtained were calcined at temperatures between 600 ¡ãC and 1100 ¡ãC. Afterwards, the product was characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). It was observed a CoAl2O4 phase in all the samples. The lowest average crystallite size was ¡Ö24 nm corresponding to the sample obtained with Asp and calcined at 600 ¡ãC, while both powders calcined at 1100 ¡ãC showed sizes higher than 200 nm. In the light of these results it is suggested the use of even higher calcination temperatures so as to obtain opaque pigments for solar collectors selective paints.