Synthesis of diamond films on W mono-blocks by MWCVD for modification of fusion materials

Abstract

Using the plate-to-plate microwave-plasma chemical vapor deposition (MWCVD) method, it is possible to deposit the diamond films on two W mono-blocks simultaneously. Substrate pretreatment was performed by sandblasting with WC particles, which resulted in excellent adhesion of the deposited films. Films with thickness up to about 200 μm and a maximum linear growth rate of 12 μm/h were deposited. Raman spectra of deposits show the presence of pure diamond phase (intense 1332 cm−1 Raman peak, without the presence of D, G graphite peaks). The XRD spectrum shows strong diamond reflections, as well as the presence of WC/W2C phase as a consequence of substrate carburization. Due to its chemical and phase purity as well as perfect adhesive property, the deposited diamond films could improve the properties of the plasma facing material under conditions of specific thermal load and chemical attack by the fusion plasma.