Tribological Properties of B4C-Ni Cermet Coating Produced by HVOF Process on the Surface of 4130 Steel

Abstract

In this research, B4C-Ni cermet coating was sprayed on the surface of 4130 steel from B4C and Ni feed-stock<br />powders using high velocity oxy-fuel (HVOF) method. In order to characterize the tribological behavior of the<br />coating, ball on disk wear tests were done at the ambient temperature and under the loads of 1, 3 and 5 N.<br />Phase analysis of the coating after spraying was studied by X-ray diffractometery (XRD). Microstructure of the<br />coating and wear track was evaluated by scanning electron microscopy (SEM), field emission scanning electron<br />microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). The microhardness test was done to measure<br />the hardness of the produced coating. It was found that a good coating with suitable interface and no significant<br />pores and cracks in the microstructure of coatings was formed. The main wear mechanism of the coating was<br />delamination with some oxide layers due to the frictional heat during wear test.