Investigation of Mechanochemical Synthesized Tungsten Silicides from WO3, SiO2 and Mg Blends

In this study, tungsten silicide powders mechanochemically synthesized using WO3-SiO2-Mg powder blends. Stoichiometric proportions and excess amounts of initial powders were used to indicate the effects of final composition of synthesized tungsten silicide powders. Since the initial powder compositions affect the reaction times, all compositions were mechanically alloyed for 1 hour. In addition, thermodynamic calculations of all compositions were theoretically conducted. The dominant phases are WSi2 and MgO for all mechanically alloyed powders. Results show that the excess amount additions of initial powders directly effects the amount and formation of resultant phases in the synthesized powder compositions.

Effect of Ar Gas Pressure on Phase Separation of Tungsten Silicides Intermetallic Compound In Situ Self-Propagating High Temperature Synthesis-Casting Process

Tungsten silicides intermetallic compound (WSi2) was synthesized in-situ by self-propagating high temperature synthesis-casting of WO3-Si-Al system in Ar gas environment. It is proposed that the extent of phase separation between oxide ceramic and intermetallic compound depends on the reaction temperature that made a lower viscosity and longer lifetime of the melted. The effects of inert gas pressure on densification of the intemetallic product were investigated.