Effect of Cr₃C₂ on particle size and coating properties of in situ generated WC particles

In order to study the inhibition effect of Cr₃C₂ on the particle size of in situ WC reinforced phase and the effect on coating properties, WC reinforced nickel-based coatings containing 0, 1%, 1.5%, 2% and 2.5% Cr₃C₂ were prepared on H13 steel surface. The microstructure of the coating was analyzed by scanning electron microscopy (SEM), and the change of WC particle size and the distribution of elements in different morphology regions of the coating were compared. The phase composition of the coating was analyzed by X-ray diffraction (XRD). The hardness of the coating was analyzed by microhardness tester. Friction and wear testing machine was used to test the friction and wear properties of the coating. The results show that Cr₃C₂ can significantly inhibit the growth of WC particles, but there is an optimal value. The main reason that Cr₃C₂ can inhibit the growth of WC grains is that Cr₃C₂ can reduce the solubility of WC in the binding phase. With the addition of Cr₃C₂, the amount of chromium in the coating increases, and the microhardness of the coating also increases. When the content of Cr₃C₂ is 2%, the microhardness of the coating is the highest. The friction and wear properties of coatings with Cr₃C₂ inhibitor are also better, and the main wear mechanism is adhesive wear.