Study on Preparation of Carbon Nanotube Reinforced In Situ WC Composite Coating by Laser Cladding

In situ WC/Ni-based coatings containing carbon nanotubes (CNTs) were synthesized using laser cladding on the surface of alloy steel. The phase and microstructure of the composite coating were characterized using SEM and XRD detection techniques. Further analysis was conducted to evaluate the morphology and distribution of reinforcing phase particles, employing thermodynamic calculations. The findings reveal that during the solidification process of molten pool, chemical reactions occur between W and C atoms, resulting in the in situ generation of regular WC. This process leads to the creation of a robust reinforcing phase involving other atoms. Remarkably, the addition of 0.1 wt % CNTs to the composite powder significantly elevated the coating hardness, reaching 1080 HV. Compared to coatings without CNTs and substrate, the wear loss is reduced by 28.6 and 50.24%, respectively. Additionally, the worn surface exhibited a smooth and flat profile, effectively resisting external loads and demonstrating the exceptional wear resistance of the composite coating.