High-Speed Laser Cladded Ni-Based WC Coatings: Microstructure, Friction-Wear Property and Wear Mechanism

Ni60WC coatings were prepared on 45 steel by laser cladding with different scanning speeds, and the effects of laser scanning speed on the microstructure, phases and hardness were analyzed using a super-depth field microscopy, x-ray diffraction and microhardness tester. The tribological performance of Ni60WC coatings fabricated at the different scanning speeds was analyzed using a ball-on-disc wear tester, and the wear mechanism was discussed. The results show that the hardness of Ni60WC coating fabricated at the laser scanning speeds of 50, 60 and 70 mm/s is 1475.0 ± 129, 1564.9 ± 117 and 1527.2 ± 140 HV_0.5, respectively, showing the coating hardness fabricated at the laser scanning speed of 60 mm/s is the highest. The average coefficients of friction of Ni60WC coatings fabricated at the laser scanning speeds of 50, 60 and 70 mm/s are 0.297, 0.344 and 0.440, respectively, and the corresponding wear rates are 949.2, 854.6 and 881.4 μm³s⁻¹N⁻¹, respectively, showing that the wear resistance of Ni60WC coating fabricated at the laser scanning speed of 60 mm/s is the best. The wear mechanism of Ni60WC coating is combined of abrasive wear and adhesive wear, which is attributed to the WC particle with the high hardness.