Effects of Electromagnetic Field on Microstructure and Properties of Ni- Based Coatings Reinforced by WC in-Situ

Abstract

The in situ WC-reinforced Ni60 laser cladding layer-assisted electromagnetic field is prepared on the H13 steel surface. The microstructure and phase of the cladding layer are analyzed by scanning electron microscope, energy disperse spectroscopy, and X-ray diffractometry, the hardness and wear resistance of the coating are tested by microhardness tester and ring-block friction and wear tester. The results indicate that more WC particles are generated with the increase in the magnetic field strength and current value, and many uniformly distributed eutectic carbides are formed in the coating, which makes the structure more uniform and dense. The average microhardness of the coating reaches 786.5HV when the electromagnetic intensity is 20 mT-9 A, and the wear amount after 90 min is 35.2 mg, which is 65.7% of the nonelectromagnetic-assisted WC/Ni60 coating and only 28.6% of the substrate, the wear resistance is obviously improved. The change in the structure and the improvement in microhardness and wear resistance are the result of the combined action of the directional Lorentz force generated by the electric field and the inductive Lorentz force generated by the magnetic field.