Improvement of Impact Resistance of WC-Cr₃C₂-Ni Based Coatings by Means of Hardness Control of Undercoat

This study shows how the impact resistance of WC-Cr₃C₂-Ni coatings can be improved by as much as an order of magnitude through the addition of an undercoat with suitable hardness. It also investigates the effect of powder modifications and substrate hardness. Undercoats with Vickers hardness ranging from400-600 HV provided the biggest increases in impact resistance, but at around 700 HV and above, they are shown to have the opposite effect. The influence of the process used to apply the undercoat and the magnitude of the impact load used for testing are also considered in the study.