Thick Ni based amorphous composite coating with good erosion wear resistance

Abstract

A thick Ni based amorphous composite coating was prepared by the laser cladding technology. The microstructure, phase composition, hardness and erosion wear resistance of the coatings were characterised by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and erosion wear experiments in this study. The results showed that the amorphous and nanocrystal composite coatings had dense structure, low porosity and metallurgical bonding with the substrate. The addition of TiB2 played a significant role in improving both the amorphous content and the mechanical behaviours of the coatings. With the increasing content of B, the hardness, erosion and wear resistance of the coatings increased. The overall performance showed better for the Ni based coating containing 20%TiB2, due to the superior combined efforts of amorphous and nanocrystallines. The hardness of the coating was about 6·5 times better than that of the 304 steel, and the erosion rate, especially at high impact angles, is superior to the commercial NiCr/Cr3C2 coating.