激光合金化Ni-W-Si涂层的组织与性能研究

Microstructure and properties of laser alloying Ni-W-Si composite coating

摘要:

以Ni-W-Si合金为原料，利用激光合金化技术在AISI 304不锈钢表面上制备了以W5Si3的复合相为增强相的Ni-W-Si涂层，用SEM、XRD与EDS等方法分析了合金的显微组织、相组成及成分，讨论了不同W、Si含量对涂层组织和耐磨性能的影响。结果表明，涂层中析出了大量花瓣状或胞状W5Si3、CrSi2及（Fe，Ni）复合相，对提高涂层抗磨损能力有良好的增强作用；含W量较高的粉末经激光合金化后残余大量未熔W颗粒，新相以其为形核中心析出并长大形成夹心结构；涂层磨损机制主要为磨粒磨损，高强韧的W5Si3相使涂层的显微硬度显著提高（最高达1040HV），并使室温干滑动摩擦磨损抗性提高了3~8倍。

Abstract:

Ni-W-Si intermetallic composite coatings with W5Si3 compound phase as the reinforcing phase were fabricated on AISI 304 stainless steel by laser alloying process using Ni-W-Si powers. The microstructure and composition of the coatings was characterized by SEM, XRD and EDS. The effect of the W、Si content on the hardness and wear resistance of coatings was investigated. Results indicate that a great deal of petaloid or cellular compound phase of W5Si3、CrSi2 and (Fe, Ni) solid solution were found after laser alloying process. Unmelted W particles were found particularly in the coatings with high proportion of tungsten. New alloy phase nucleated and grown into petaloid structure around W. The wear mechanism was mainly abrasive wear. Attributed to the high hardness and toughness of W5Si3, coatings had high hardness (the highest being 1040HV) and the wear resistance was elevated to 4~8 times higher.