不锈钢表面激光熔覆无钴镍基合金涂层研究

为满足某装置用阀门密封面材料不能含有钴的要求,通过激光熔覆两种无钴镍基合金粉末,在0Cr18Ni10Ti不锈钢表面制备出具有梯度硬度分布的较厚涂层,分析了涂层的微观组织、硬度及界面结合强度。结果表明,采用硬度较低的镍基合金涂层作为过渡层,解决了具有较高硬度镍基合金涂层的开裂问题;涂层与基体及两种镍基合金涂层之间界面连续过渡,硬度呈梯度变化,涂层表面硬度达HRC47;涂层与基体界面为完全冶金结合,其界面结合强度大于565MPa;经弯曲及热震试验后,涂层未出现开裂及剥落现象,说明涂层具有良好的抗热震性能。

Study on laser clad cobalt-free nickel-based alloys coatings on stainless steel

To meet the cobalt-free requirement for a certain valve, thicker coating with gradient hardness distribution was prepared on 0Cr18Ni10Ti stainless steel by laser cladding two kinds of cobalt-free nickel-based alloy powder. The microstructure, hardness and the interface bonding strength of the coating were analyzed. The results showed that using nickel-based alloy with lower hardness as a transition layer, the problem of cracking for nickel-based alloy coating with higher hardness could be resolved. The interfaces between the coating and the substrate as well as these two nickel-based alloy coatings were smoothly transited. The hardness was also gradient along the cross-section of the coating. The hardness of the coating surface was about HRC 47. The coating was metallurgically bonded with the substrate. And the interface bonding strength of the coating was higher than 565 MPa. There was no de-bonding and cracking after bending and thermal shock test, indicating the good anti-thermal shock property of the coating.