Effect of heat treatment at 1300A degrees C on W coating prepared by double-glow plasma on carbon/carbon composite

W-coated carbon/carbon composite has been considered as an attractive ITER plasma facing material in fusion devices. In this paper, W coating was prepared on the carbon/carbon composite substrate by double-glow plasma method using pure W as target. Argon was input into the chamber as the plasma and the reactive gas. W-coated carbon/carbon composite was heat-treated in vacuum furnace at 1300A degrees C for 1 h. Phase and microstructure of W coating were examined by X-ray diffraction and scanning electron microscopy, respectively. The chemical composition of W coating was analyzed by energy dispersive spectroscopy. The micro-hardness of the W coating was estimated by nano-indentation instrument. The results indicated that a continuous and dense W-modified layer could be successfully coated on the carbon/carbon composite surface by double-glow plasma method. W coating completely reacted with C to form WC at 1300A degrees C. WC almost completely diffused into the carbon/carbon composite after heat treatment. The great decrease in elemental W on the carbon/carbon composite surface after heat treatment led to a significant reduction in micro-hardness.