DETERMINACION DE LA CONDUCTIVIDAD TERMICA EN POLVOS AISLANTES TÉRMICOS DE MgO A ALTA TEMPERATURA: EFECTO DE LA DISTRIBUCION DEL TAMAÑO DE GRANO E IMPUREZAS.

Abstract

MgO is one of the most important products of magnesium used in industry. Mexico is one of the largest producers of MgO, the states of Nuevo Leon and Coahuila, with large deposits of high purity dolomite, which is obtained MgO by calcination processes [1]. Because of its poor electrical conductivity and thermal conductivity at high temperatures the MgO powder is used extensively by manufacturers of electrical resistance, and its primary application Fluid warming. In every industrial application MgO powder requires specific characteristics, the critical parameters are: particle size, density, activity and chemical purity [2]. Here we report the determination of thermal conductivity at high temperatures (259 – 860 ° C) in electrical grade MgO powders with different grain sizes (53 to 420  m), using the technique of radial heat flow in steady state according to the standard of the American Society for Testing and Materials (ASTM) 2858-90, and a composition analysis by EDS and XRD[3]. [1] Lide, David R., ed. Handbook of chemistry and Physics, 78th edition, pp B-7, B-8 y B-24 (1998). [2] A.N. Copp., Am. Ceram. Soc. Bull. 75, 135 (1996) [3] Gabriel Peña Rodríguez, Tesis de Doctorado, Microestructura y caracterización térmica en sólidos y polvos de interés industrial, CICATA-IPN, Mexico D.F. Agosto de 2003.