Electrospark deposition of Al2O3–TiB2/Ni composite-phase surface coatings on Cu–Cr–Zr alloy electrodes

Ping Luo, Shijie Dong, Anzhuo Yangli, Shixuan Sun, Zhong Zheng, Huihu Wang
2015 Journal of Asian Ceramic Societies  
To improve electrode life during the resistance spot welding of galvanized steel plates, an Al 2 O 3 -TiB 2 composite coating was synthesized on the surfaces of spot-welding electrodes through an electrospark deposition process. The microstructure, elemental composition, phase structure, and mechanical properties of the coating were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and microhardness testing. It was found that
more » ... was found that extensive cracking occurred in the monolithic Al 2 O 3 -TiB 2 coating and at the coating-electrode interface. When the Al 2 O 3 -TiB 2 coating was deposited on electrodes precoated with Ni, the number of defects decreased significantly. Further, delamination did not occur, and fewer cracks were formed. The average hardness of the multilayered Al 2 O 3 -TiB 2 /Ni coating was approximately 2200 HV and higher than that of the monolithic Al 2 O 3 -TiB 2 coating (1100 HV).
doi:10.1016/j.jascer.2014.11.005 fatcat:ehssjrusmfdjbkxv3bei6zeg4i