A New Asperity-Scale Mechanistic Model of Tribocorrosive Wear: Synergistic Effects of Mechanical Wear and Corrosion

Abstract

A corrosive wear model is considered at the asperity-scale of a tribocorrosive wear system as well as the traditional Archard-type mechanical wear model. The geometry of the surface asperities is modified in a contact mechanics model with respect to both corrosive and mechanical wear calculations. This model was presented and validated for prediction of the electrochemistry in the first part of this work. The material used in the experimental part of this work was CoCrMo plate working electrode (WE) and Si3N4 ball as the counter body in a reciprocating configuration. Experiments were conducted at loads of 5, 7.5, and 10 N and the contributions of total mechanical wear and corrosion were measured. The model is then tuned to predict the chemical and mechanical components of the total wear of the system. The synergistic effect of corrosion on mechanical wear and mechanical wear on corrosion are modeled numerically in this work. The values are then used to explain different components of mechanistic tribocorrosive wear models present in the literature. This deterministic model, for the first time, calculates the corrosion-enhanced wear in a tribocorrosive wear environment and proposes that changes in the topography are responsible for this synergistic effect. The results show a linear dependence of the corrosion enhanced wear, wear-enhanced corrosion, and the pure mechanical wear on the applied load. Results also suggest that the wear enhanced corrosion has a significant contribution in the overall degradation of the material.