Tribocorrosion properties of polycrystalline diamond compact in saline environment

Tribocorrosion properties of polycrystalline diamond compact (PDC) in solution containing sodium chloride were investigated using a modified pin-on-disc wear test rig. Tests were conducted at various salinities (0-20%) for a better understanding of the abrasion-corrosion interaction. The corrosion behavior was examined through a three-electrode electrochemical cell. The contributions of pure abrasion and pure corrosion as well as their synergy to the total volume loss were calculated. The influence of cathodic protection on the abrasion-corrosion performance of PDC was also evaluated. Experimental data in this paper shows that the PDC suffers more severe damage as the sodium chloride concentration increases gradually and the applied potential of -1.0 V vs. SCE can suppress the corrosion-related effects to a negligible level. Both electrochemical measurements and SEM micrographs of worn surfaces were used to detail the degradation mechanism. Despite the fact that it is the mechanical wear that dominates the abrasion-corrosion mechanism, results reveal that the interaction between the abrasion and corrosion plays a significant role. Moreover, an effective volume calculation method based on three dimensional point cloud was proposed to determine the wear volume of PDC. Validation studies demonstrate that the measurement method is feasible and accurate with an error of no more than 5%.