Synergistic effects of micro-abrasion-corrosion of UNS S30403, S31603 and S32760 stainless steels

In this study, the synergistic effects of abrasion and corrosion on UNS S30403, S31603 and S32760 stainless steels have been investigated using a micro-abrasion test rig. The stainless steel samples have been studied under both pure abrasion (PA) and abrasion-corrosion (AC) conditions simulated by using silicon carbide based slurries in either distilled water or 3.5% sodium chloride solutions. Tests have been conducted at various abrasive concentrations (0.006-0.238 g/cm3) and at 38 and 180 m sliding distance to enable the interactions between abrasion and corrosion to be better understood. Wear mode identification and regime mapping was used to establish the dominant wear mechanism at the different slurry concentrations. The synergistic effect has been quantified and related to the material composition and the grooving or rolling abrasive wear mechanisms present. The synergistic levels were typically positive and have been discussed in terms of their dependence on the integrity of the passive films and the repassivation kinetics. The three-body abrasion-corrosion rates for all steels were found to be 14 times higher than two-body abrasion-corrosion rates. S30403 shows weak repassivation performance with electrochemical activity being proportional to mechanical activity. S31603 showed a constant electrochemical activity over a variety of mechanical conditions, indicating a stronger repassivation performance than S30403. S32760 has the best repassivation performance with negative synergistic characteristics until abrasion rate are such that depassivation occurs and the electrochemical activity is then comparable to the other steels.