Two reactant systems for self-propagating high-temperature synthesis of tungsten silicide
- 18 Downloads
Tungsten silicide (WSi2) intermetallic was prepared via self-propagating high-temperature synthesis (SHS) from two reactant systems: one using scheelite (CaWO4-Si-Al) and the other pure oxides (CaO-WO3-Si-Al). The equilibrium compositions of the reactions were calculated by a standard Gibbs energy minimization. Reactant mixtures were high-energy milled for durations of 0.5, 2, 4, and 8 h and the effects of milling on the synthesized products were studied. The effects of the sand mold on the products were also studied. The phase constituents and microstructural morphologies of the products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDS) capability. Intermetallic WSi2 was successfully synthesized from both systems. The system that contained the pure oxide (CaO-WO3-Si-Al) reactant gave a higher yield of WSi2 than the system that contained scheelite (CaWO4-Si-Al) but the yield from the CaWO4-Si-Al reactant system could be optimized by increasing the proportion of Si in the system. The sand mold helped the phase separation of the oxide slag and the intermetallic.
KeywordsSelf-propagating high-temperature synthesis WSi2 CaWO4 High-energy milling Sand mold
The authors also sincerely thank the Ceramic and Composite Materials Engineering Research Group (CMERG), Center of Excellence in Materials Engineering (CEME), Faculty of Engineering, Prince of Songkla University (PSU), Thailand. Also, the authors were highly grateful to Mr. Thomas Duncan Coyne for suggestions and improvements to the English text.
The authors gratefully acknowledge the support for this work from Thailand’s Education Hub for Southern Region of ASEAN Countries Project Office of the Higher Education Commission (TEH-AC).
- 4.Merzhanov, A.G.: Theory and practice of SHS: worldwide state of the art and the newest results. Int J Self-Propag High-Temp Synth. 2, 113–158 (1993)Google Scholar
- 12.Niyomwas, S.: Synthesis and characterization of silicon-silicon carbide composites from rice husk ash via self-propagating high temperature synthesis. J Met Mater Min. 19, 21–25 (2009)Google Scholar
- 18.Outokumpu HSC Chemistry® for windows, version HSC 4.1. Finland: Outokumpu Research Oy; (1999)Google Scholar
- 19.Ramos, J., Hernández, J., Cambeses, A., Scarrow, J., Galindo, A.: Pathways for quantitative analysis by X-ray diffraction, an introduction to the study of mineralogy. Cumhur Aydinalp (Ed.) In Tech, Croatia (2012)Google Scholar