Synthesis WSi2 coating on W substrate by HDS method with various deposition times

Abstract

The hot dip silicon-plating method (HDS) is used to deposit a two-layer silicide coating on tungsten substrate. The growth behavior, microstructure, and phase composition of silicide coating are investigated. The silicide coating is composed by out layer (WSi2 layer) and interfacial layer (W5Si3 layer), which have a very dense, smooth and homogenous surface microstructure. The coating surface has a higher silicon concentration (34.90 wt%) with a surface composition of WSi2-14.97 wt%Si under the deposition time is 25 min. The grain sizes and thicknesses of WSi2 coatings show a trend of gradual increase with increasing deposition time. However, the thicknesses of interfacial layers (W5Si3 layers) present a parabolic shape with increasing deposition time, which is due to the W5Si3 phase spontaneously transforms into WSi2 at high temperature with a sufficient silicon source.