Tungsten Coating for Thermal Fusion Material Produced by Gas Tunnel Type Plasma Spraying

Tungsten (W) is a material which has the highest melting point of 3422 ℃ among metals. Therefore when deposited as a coating it can protect the substrate surface from high heat flux. The W composite will be a superior candidate for thermal fusion materials. In this study, tungsten sprayed coatings were produced on stainless steel substrates by gas tunnel type plasma spraying at a short spraying distance (40mm). The Vickers micro-hardness of the W coating was measured as the mechanical property. The tungsten coating had a hardness of Hv=260-300 along its cross section, which is a little lower than the hardness for bulk tungsten. Regarding the microstructure the coating contained some pores. The results of X ray Diffraction show that the coating consists of pure tungsten, without oxidation