【摘要】 为了提高镀锌钢板点焊电极的寿命,以TiC为沉积材料,在铬锆铜球型点焊电极表面进行了电火花振动沉积功能涂层的工艺试验,研究了首次单点沉积、限时沉积、清洗前处理、扩散后处理等方法获得功能层的显微组织与性能。结果表明,首次单点沉积后功能层呈溅射状,类似树枝晶。限时沉积后材料由强化层、过渡层、热影响区、基体组成。强化层结构致密、硬度很高;过渡层有微孔及微裂纹,存在明显的元素互扩散,表明功能层与基体之间为冶金结合。通过清洗前处理可改善过渡层的显微组织,而不影响功能层硬度;而扩散后处理改善了过渡层的组织,但降低了功能层的硬度与厚度。更多还原

【Abstract】 Functional TiC coating was deposited on the surface of Cr-Zr-Cu spot-welding electrode by vibrating electrospark deposition.Microstructure of the functional coating of single-pulse and timed deposition with pre-treatment(cleaning) or post-treatment(diffusion) were tested,respectively.The results indicate that microstructure of the first-pulse deposited coating is dendrite-like crystalline with splash appearance.The coating formed by timed deposition consists of white layer,trasition layer,heat affected zone and substrate.Some micro-pores and micro-cracks in transition layer can be observed after multi-time deposition.Mutual diffusion of Ti and Cu in the transition layer occurs in the process of post-treatment after deposition.The metallurgical bonding between the coating and the substrate is confirmed by experiment.Cleaning treatment of the substrate can improve the coating microstructiure with little influence on its hardness,however,post-treatment after depositicon amends the coating structure,reduces its hardness and thickness,and it is hopeful to prolong the service life of the electrode due to occuring of alloy elements diffusion to reduce defects in the coating and the formation of metallurgical bonding between the coating and substrate.更多还原