Microstructure and properties of laser cladding in-situ ceramic particles reinforced Ni-based coatings

In order to explore the effect of in-situ ceramic particles on the microstructure and properties of nickel-based composite coatings, the nickel-based coatings reinforced by the in-situ ceramic were prepared on the surface of 40CrNiMo steel using laser cladding technology. On the basis of NiCrBSi (Ni45) powder, 0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% of B4C and ferrovanadium (FeV50) were added, which the atomic ratio of V to C was 1:1. Microstructure and phase analysis were carried out by metallographic microscope (OM), X-ray diffractometer (XRD), and scanning electron microscope (SEM). The results show that the NiCrBSi coating without B4C and FeV50 are mainly composed of ?-Ni, Cr23C6, Cr7C3, and CrB phases. After adding B4C and FeV50, the matrix is mainly composed of ?-Ni(Fe) solid solution, and strengthening phases such as CrB2 and VB2 appear in the coating. With the increase of the B4C and FeV50, the amount of CrB2 and VB2 increased, and the hardness and wear resistance were improved. When the addition amount of B4C and FeV50 is 10 wt%, the in-situ reinforced particles were uniformly distributed and the wear resistance of the coating was the best and was about 15 times that of Ni45 coating.