Low-temperature synthesis of BaAl2O4 aluminum-bearing composites by the oxidation of solid metal-bearing precursors

BaAl2O4/aluminum-bearing composites have been synthesized via the low-tempe rature oxidation of Ba-Al precursors. Ba-Al powder mixtures that were prepa red via high-energy vibratory milling were uniaxially pressed into bar-shap ed specimens that were then exposed to a series of heat treatments in pure, flowing oxygen at temperatures up to 640 degrees C. Oxidation at a tempera ture of 300 degrees C resulted in the formation of barium peroxide (BaO2). Additional heat treatment at a temperature of 550 degrees C resulted in the consumption of BaO2 and some aluminum to yield BaAl2O4 and Al4Ba. The oxid ation of Al4Ba at a temperature of 640 degrees C yielded additional BaAl2O4 . Microstructural analyses revealed that a well-dispersed, co-continuous mi xture of Al2O3-excess BaAl2O4 and 99.5% pure aluminum was produced.