Study on the Microstructure and Performance of the Multi-Field Composite-Assisted Laser Cladding of Nickel-Based Tungsten Carbide Coatings

Abstract

Improving the hardness and wear resistance of die cutting tools is an important issue in the study of the service life of die cutting equipment. Using laser cladding technology, nickel-based composite coatings with varying BiFeO3 contents were prepared on a 45 steel substrate, because BiFeO3 can have an effect on the dilution rate and microstructure of the sample; morover BiFeO3 is a new type of multiferroic material with certain magneto-electric coupling effects which can be prepared for the study of added magnetic fields. The microstructure and morphology were characterized to determine the optimal BiFeO3 content. Based on the optimal addition of BiFeO3, a comparative analysis was conducted to investigate the effect of different magnetic field strengths under a composite energy field on the microstructure, hardness, and wear resistance of Ni-based WC cladding layers. The results show that the optimal addition of BiFeO3 was 5 wt%. At this concentration, there were no significant porosity defects in the coating, and the dilution rate was appropriate (4.77%). Additionally, the interface bonding strength was also increased. With optimal BiFeO3 addition, stirring with different magnetic field strengths was applied to the cladding layer, and the results show that the aspect ratio of the cladding layer gradually increased with increasing the alternating magnetic field strength. When the magnetic field strength in the composite energy field was 40 mT, the microstructure was fine and uniform, the hardness of the cladding layer reached the highest level, about 925.2 HV1.0, the wear resistance was also the best, the friction coefficient of the cladding layer was about 0.54, and the width of the wear mark was about 0.53 mm.

Keywords

• laser cladding
• BiFeO₃
• magnetic field
• hardness
• friction and wear