不锈钢基体上激光熔覆原位合成制备TiB_2/WC增强镍基复合涂层

Ni-based Composite Coatings Reinforced by TiB_2/WC Synthesized in Situ on Stainless Steel by Laser Cladding

采用激光熔覆原位合成技术在不锈钢基体表面制备了TiB2/WC增强镍基复合涂层,用X射线衍射仪、能谱仪、扫描电镜等对涂层进行了分析,并对涂层进行了热震试验。结果表明:涂层致密、厚度均匀、表面平整、无裂纹和孔隙、与基体呈冶金结合;涂层主要由TiB2、WC、γ-Ni等物相组成,细小的TiB2和WC粒子主要分布于γ-Ni枝晶间,可阻碍基体晶粒晶界的推移长大;WC颗粒主要分布于涂层中部和下部区域,原位合成的细小TiB2粒子主要分布于涂层上部;涂层具有较高的抗裂能力,与基体具有良好的结合强度。

The Ni-based composite coatings reinforced by TiB2 and WC were prepared on the stainless steel substrate by laser cladding. The coatings were analyzed by means of X-ray diffraction, X-ray energy dispersive spectroscope, scanning electron microscope and thermal shock experiment. The results indicate that the coatings were dense, smooth, uniform, free of cracks and pores, and had good adherence to the substrate. The coatings were composed of TiB2, WC and γ-Ni phases and the fine TiB2 and WC particles mainly dispersed at grain boundaries of γ-Ni dendrite and hindered the expansion of the grain boundaries. WC particles mainly dispersed at the middle and bottom zones after the laser cladding. TiB2 grains synthesized in situ were fine and mainly distributed at the upper zone. The coatings pocess a good metallurgical bond with the substrate and excellent cracking resistance .