Research on preparation optimization of nano CeB6 powder and its high temperature stability

Abstract

High temperature self-propagating synthesis (SHS) process is very rapid, the reaction process becomes un-controlled after the SHS reaction is ignited. So the initial reaction conditions will have great effects on phase compositions and microstructures of reaction products. In this paper, the effects of the proportioning amount of Mg on the yield ratio and particle sizes of CeB6 were studied. The SHS reaction products and leached products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the SHS products consisted of MgO, CeB6 and little Mg3B2O6. The single CeB6 phase was contained after the SHS reaction products were leached. The purity of CeB6 was higher than 99.0 mass%, and the minimum particle sizes of CeB6 were within 30–70 nm. When the proportioning amount of Mg was 25% more than the theoretic amount, the yield of CeB6 was 68.68%. The antioxidant ability of CeB6 was rather stronger, which was oxidized step by step, and the initial oxidation temperature was 750 °C, which indicated that it had good high temperature stability. The apparent activation energies of oxidation reactions of CeB6 were 200.09 and 312.10 kJ/mol, respectively, and reaction orders were 0.69 and 0.40, respectively.