利用Na₂WO₄-WO₃熔盐体系在V-4Cr-4Ti合金基体上电沉积制备了金属W涂层,在电流密度为10-160 mA/cm²范围内研究了电流密度对金属W涂层的显微结构和力学性能的影响.研究结果表明, 增大电流密度促进了W晶核的生长以及晶粒尺寸的增大. W原子更容易在V-4Cr-4Ti合金基体上形核,而在初始W晶核上继续沉积主要是W晶核长大的过程,电流密度较大(100 mA/cm²)时, W涂层的金相组织呈柱状和条状结构, 电流密度较小时,W涂层组织呈牙柱状. W涂层的硬度随着电流密度的增加而下降,W涂层与V-4Cr-4Ti合金基体的结合强度超过59.36 MPa. 电流密度为10 mA/cm²时, 虽然涂层厚度仅有10 μm, 但W涂层晶粒尺寸小于5 μm, 涂层硬度、电流效率以及涂层和基体的结合力达到最大值, 分别为628.42 HV, 99.71%和96 N.

The W coatings prepared on structure materials (V-4Cr-4Ti) as plasma facing materials, not only can release impinging thermal power but also can resist erosion under plasma particles bombardment in international thermonuclear experimental reactor. The electro deposition of W in Na₂WO₄-WO₃ melt as a promising technique was studied in this work. The effects of current density on microstructure and mechanical properties of W coating were investigated, and the results show that, with the increasing of the current density, the trend of crystal growth is promoted and the grain size of W coatings increased. The nucleation easily occurs on V-4Cr-4Ti alloy substrate for W atom, and after that, the growth of crystal nuclei is the most important factor for the formation of coatings. When the current density increases to 100 mA/cm², the metallographic structure of W coatings presents columnar or stripy structure, and tooth-like grains were presented in microstructure as current density is lower. The Vickers micro-hardness of W coatings is decreased as increasing current density, and the adhesive strength of the coatings is greater than 59.36 MPa by the tensile test. Although the thickness of tungsten coatings is 10 μm as current density is 10 mA/cm², grain size is less than 5 μm, Vickers hardness, current efficiency and the coatings adhesion are all maximum, and the values are 628.42 HV, 99.71% and 96 N respectively.