Microstructure and wear resistance of laser-clad Ni60-Ti-B4C coatings.

In order to improve the surface performance of engineering components, a Ni60-Ti-B4C hard coating was prepared in-situ on the surface of Q235 using laser cladding method based on Ni60-Ti-B4C powder. The effect of process parameters (laser power and scanning speed) on the microstructure, dilution rate, microhardness and wear resistance of the coatings was investigated in detail. The highest microhardness and lower dilution rate coatings were obtained by process optimization. A laser power of 1000 W and scanning speed of 6 mm/s were found to be the optimum parameters. The optimized Ni60-Ti-B4C coating mainly consists of in-situ rod-like TiB2 and block-like TiC of different sizes with TiB2-TiC eutectic structure and small amounts of FeNi, Ni3Cr and NiSi phases. The optimized Ni60-Ti-B4C coating has a dilution rate of 27.1% and a wear loss of 2.1 mg. The microhardness is 1278 HV0.3, which is about 7 times of the microhardness of Q235 steel substrate, and 2.5 times the microhardness of laser cladding coated Ni60 coating. The abrasion of the Ni60-Ti-B4C coating is mainly adhesive abrasion. This study can provide a reference value for the use of surface technology to improve the overall performance of metal parts. [ABSTRACT FROM AUTHOR]