Volume 26, Issue 4 (July 1998)
Pin-on-Disk Corrosion-Wear Test
An electrochemical pin-on-disk corrosion-wear apparatus was developed at the Albany Research Center of the U.S. Department of Energy. The instrument was qualified on a low-alloy T1 tool steel [ASTM A 514] and a 304 stainless steel (Type 304). The apparatus incorporates simple specimen and counterface geometry and is instrumented for simultaneous corrosion and wear testing. The electrochemical and wear parameters of potential, current, charge, sliding speed, frictional force, and normal acceleration can be continuously displayed and recorded. After a break-in period, the electrochemical pin-on-disk produced constant wear rates independent of path length for both ASTM A 514 steel and 304 stainless steel. Results for 304 stainless steel in sulfate solutions show that abrasive wear causes the corrosion potential to shift by 0.4 V in the active direction and the passive current density to increase by three orders of magnitude, compound with the condition of no wear. Current density was a linear function of the sliding speed at a constant applied anodic potential. The open circuit corrosion potential exhibits a decay function behavior with respect to the sliding speed. Volume loss and corrosion measurements showed that mechanical removal of material was responsible for 95% of the corrosion-wear losses for 304 stainless steel. Continual corrosion exposure, however, increased the mechanical removal of material by 35 to 48%.