Influence of loading levels on RCF life and failure mode of Ni-based alloy and WC–Ni ceramic composite coatings

• RCF performance of NiCrBSi/WC–Ni coating was studied on a double-roller test-rig.
• Abrasion, spalling, delamination, and rolling cracking were main failure modes.
• Main RCF failure modes of NiCrBSi/WC–Ni coating were related with contact stress.
• RCF life became more difficult to predict as contact stress increased.
• RCF life can be predicted by established lognormal distribution and σmax − N model.

This paper studied influence of loading levels on rolling contact fatigue (RCF) performance of NiCrBSi/WC–Ni composite coating. The results showed that abrasion, spalling, delamination, and rolling cracking were four kinds of main failure modes related with contact stress. Under relatively high contact stress, intense deformation of NiCrBSi particles resulted in rolling cracking failure. Furthermore, RCF life can be predicted by established lognormal distribution and σmax − N model. The study also found that RCF life was closer to expectation E(N), higher failure probability of the coating. And RCF life became more discrete and more difficult to predict as contact stress increased.