Synthesis of nano-structure molybdenum disilicide from primary mixture of MoO3 + Si + Al through mechanochemical reactions

Abstract

The formation of nanocrystalline molybdenum disilicide intermetallic compound from the primary mixture of MoO3+Si+Al by mechanochemical synthesis (MS) method via mechanical milling was investigated. The mechanochemical processes were designed based on thermodynamic calculations and with the aim of studying the effects of changing the Al amount of the primary mixture. An MSR (mechanically induced self-propagating reaction) process was done using a high-energy planetary ball mill. The experiments were optimized to increase the amount of low temperature α-MoSi2 phase and convert the unstable β-MoSi2 phase to the stable α-MoSi2 phase. With the aid of XRD (X-ray diffraction) experiments, phases and their microstructure were analyzed. EDX (energy dispersive X-ray) experiments were carried out in order to investigate the composition of the products and TEM (transmission electron microscopy) was used to study powder particles. The crystallite size and the particle size of the obtained α-MoSi2 phase were around 18.2 and 179nm, respectively. The mass fraction of each obtained phase was determined employing the semi-quantitative analysis of X-ray diffraction patterns.