打壳锤头等离子堆焊Co—Cr—W合金涂层组织和性能研究

采用等离子堆焊技术在铝电解打壳锤头表面堆焊Co-Cr-W合金粉末。利用光学显微镜、扫描电镜、能谱仪和显微硬度计等，分析了堆焊层的微观组织、微区成分和硬度分布。利用恒电位法进行腐蚀模拟测试。试验结果表明，合金层为典型的等轴晶和柱状晶组织，与基体之间形成了良好的冶金结合。合金层外层硬度最高，平均硬度为基体的2倍，从合金层到基体硬度值不断减小，在熔合线附近迅速降低，表明合金层稀释率较低。合金层的腐蚀速率为基体的1／53左右，合金锤头的耐腐蚀性显著提高。

Microstructure and Properties of Co-Cr-W Alloy Layer by Plasma Surfacing Process on Crust Breaker

The Co-Cr-W alloy powder was deposited on the surface of crust breaker for alumi- num electrolysis cell by plasma surfacing process. Microstructures, composition and microhard- ness of this alloy layer were investigated by OM, SEM, EDS and microhardness system. The potentiostat was used to do simulation test of the corrosion rate of plasma surfacing layer and the matrix metal. The results show that the alloy layer consists of the isometric crystal and co lumnar crystal, and it is well bonded to the matrix metal. The highest hardness of the alloy layer exists on the surface and the average microhardness of the plasma surfacing layer is 550 HV0.1, which is 2 times of the matrix one. The hardness decreases from alloy layer surface to the matrix and it comes down sharply near the fusion line, which indicates the low dilution ratio of the alloy layer corrosion resistance The alloy layer＇s corrosion rate is about 1/53 of the matrix metal, and the of the material is obviously improved.