面向等离子体材料钨厚涂层的制备及表征

等离子体喷涂技术在面向等离子体材料钨涂层的制备中占据主导地位,本实验采用CuMo/MoW作为涂层的中间过渡层,分别以结晶钨粉和羰基钨粉为原料,用大气等离子体喷涂技术在CuCrZr合金基体(110 mm×130mm)上制备了3-4 mm厚的3种钨涂层.对钨涂层微观组织、力学性能和热学性能研究表明,羰基钨粉制备的钨涂层的综合性能优于结晶钨粉,且薄涂层的结合强度优于厚涂层.优化喷涂工艺后,金相法测得钨涂层孔隙率＜2％,涂层的结合强度最大值为10 MPa,EDS测得氧含量为6％左右,纯钨层热导率最大值为12.52 W/(m.K),涂层氧含量过高导致涂层热导率显著降低.研究表明采用大气等离子体喷涂技术在铜合金上制备3～4mm厚的钨涂层是可行的,该技术可为下一步低成本、高性能厚钨涂层的制备奠定基础.

Preparation and Characterization of Thick Tungsten Coatings for Plasma Facing Materials

Plasma spray (PS) is the dominant technology for preparing tungsten (W) coatings used as plasma facing materials (PFM). Two types of tungsten powders, i.e. crystal tungsten powder and carbonyl tungsten powder, produced by different methods, were adopted during plasma spray. Three thick tungsten coatings with thickness of 3-4 mm on copper-chromium-zirconium (Cu, Cr, Zr) alloy substrate with 110 mm × 130 mm were fabricated by means of atmospheric plasma spray (APS). The CuMo/MoW was used as the interlayer of tungsten coatings. Characterization of coatings was performed in order to assess microstructure, mechanical and thermal properties. The results indicate that the coating from carbonyl tungsten powder has better over-all properties than that from crystal tungsten powder, and for the coatings from the same powder, the thin coating possesses higher bond strength than the thick. The porosity of the coating is less than 2% by digital image analysis. The maximal tensile strength value of coatings is about 10 MPa. The content of oxygen is about 6 wt% by EDS. The maximal thermal conductivity of the pure tungsten coatings is 12.52 W/(m·K). The high oxygen results in the low thermal conductivity of the tungsten coating. The work performed has demonstrated the feasibility of 3-4 mm thick W coatings on flat geometries by APS, which is the foundation of preparing the low cost and high property thick tungsten coatings.