WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

International audienceHigh current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 vs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope ( SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC1 _,, CO3 W9 C4, CO3 W3 C phases and graphite precipitate domains 50 nm. The friction coefficient of modified surface decreased to 0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 x 10-5 mm3 /min to 6.3 x 10-6 mm3 /min, showing a significant self-lubricating effect