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以Ni25、WO_3、Al、石墨混合粉体为预制合金材料采用YAG固体激光器进行激光熔覆处理,在45钢表面原位合成了W_xC颗粒增强镍基复合涂层。利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)对涂层显微组织、相组成以及硬质颗粒的分布进行了观察、分析。结果表明在高能激光辐照下,可以获得WC、W_2C、W_3C、Cr_7C_3弥散分布的多元硬质相增强的镍基复合涂层。W_xC颗粒尺寸小于200 nm。涂层组织致密、无裂纹和孔洞等缺陷与基体间有良好的冶金结合。涂层的显微硬度最高可达900 HV0.2,为45钢基体的4.5倍。
The Ni_25, WO_3, Al and graphite mixed powders were pre-alloyed by YAG laser and the W_xC particles reinforced nickel-base composite coating was synthesized in-situ on the surface of 45 steel. The microstructure, phase composition and hard particle distribution of the coating were observed and analyzed by SEM, EDS and XRD. The results show that the WC-W2C, W_3C and Cr_7C_3 dispersed Ni-based composite coatings with multiple hard phases can be obtained under high-energy laser irradiation. W_xC particle size is less than 200 nm. The coating has the advantages of compact structure, no cracks and defects such as holes and good metallurgical bonding with the substrate. The coating has a microhardness of up to 900 HV0.2, 4.5 times that of a 45 steel substrate.