Tribocorrosion mechanisms of NiCrMo-625 alloy: An electrochemical modeling approach

The analysis presented in this work provides a tentative explanation to the large wear rate differences registered in the normal load range of 6-70 N for the sliding tribocorrosion of NiCrMo625 alloy in 3.4%wt NaCl aqueous solution by means of making the association of volume loss and wear track surface morphology with the CoF values measured. A transition from a nanowear mechanism towards fatigue wear was found to occur between 15 N and 35 N normal load. Furthermore, mathematical modeling of the tribocorrosion parameters at high loads have enabled to monitor the time evolving wear characteristics of this process and have assisted in confirming the influence of the changing surface condition of the counterpart and of the contact area curvature on the observed wear. The triboelectrochemical model prediction of the ideal OCP behavior over the experimental time domain provided insight to the increasing potential divergence measured after 300 s, proven to be an effect of the presence of debris particles. A correlation between the varying wear rate, the contacting surface topography and the recorded variations in the CoF over the 3000 s time domain of continuous tribocorrosion at 35 N against alumina, is also proposed.