Changes of composition and microstructure of joint interface of tungsten coated carbon by high heat flux

Tungsten coatings of 0.5 and 1 mm thickness were successfully deposited by the vacuum plasma spraying (VPS) technique on carbon/carbon fiber composite (CFC), CX-2002U and isotropic fine grained graphite, IG-430U, High heat Au x experiments by irradiation of electron beam with uniform profile were per formed on the coated samples in order to prove the suitability and load lim it of such coating materials. The cross-sectional composition and structure of the interface of VPS-W and carbon material samples were investigated. C ompositional analyses showed that the Re/W multi-layer acts as diffusion ba rrier for carbon and suppresses tungsten carbide formation in the VPS-W lay er at high temperature about 1300 degreesC. Microstructure of the joint int erface of the sample changed in the case of a peak temperature of about 280 0 degreesC. The multi-layer structure completely disappeared and compositio nal distribution was almost uniform in the interface of the sample after me lting and resolidification. The diffusion barrier for carbon is not expecte d to act in this stage. (C) 2000 Elsevier Science B.V, All rights reserved.