Advanced materials are the crucial factors determining the successful application of future nuclear fusion energy. Plasma facing materials (PFMs) are one of the most important armor materials in nuclear fusion experiment devices for direct facing with the extremely high thermal load, thermal shock and strong irradiation of high energy particles. W coated CuCrZr substrate has been considered as one of the candidates to the armor materials due to its high melting point, chemical stability and good thermal conductivity. However it was a challenge to obtain high strength thick W coatings because of the major difference of CTE between the W and CuCrZr substrate. In this paper, graded W/Cu layers were deposited as the bond layer via Low Pressure Plasma Spraying (LPPS) on the CuCrZr substrate. Subsequently, thick LPPS W coatings over 1.5 mm were prepared as the top layer. The adhesive and cohesive strengths for thick W coatings on CuCrZr substrates were evaluated according to the standard of ASTM C633. The results showed that the oxide formation on the W coating surface rapidly deteriorated the coating microstructure and properties.

Low pressure plasma spray (LPPS) technology has exhibited its advantage in deposition of yttria stabilized zirconia (YSZ) coating. The YSZ coatings deposited under different chamber pressures were characterized by XRD and SEM in this paper. Preliminary results showed that as-sprayed coatings contained partially-melted zone, and increased chamber pressure was beneficial to the melting of particle. It was revealed that as-sprayed coatings were mainly composed of metastable tetragonal phase except for minor content of cubic phase analyzed by XRD. Compared to air plasma spray (APS) coating, the microhardness and toughness of well-flatten LPPS coating are respectively high and excellent.