Mechanisms responsible for synergy between fretting and corrosion for three biomaterials in saline solution

摘要

The material removal caused by synergistic interaction of fretting and corrosion is much larger than the summation of individual fretting and corrosion loss. The increment of removal should result from the synergistic effect of mechanical and corrosive losses of materials, i.e. the acceleration of corrosion by fretting and the increase of fretting by corrosion. The fretting corrosion behaviors of three biomaterials, 316L stainless steel, Co-Cr-Mo and Ti-6Al-4V alloys were investigated. The total removals of materials should come from five components, pure corrosion, pure wear, corrosion increment caused by fretting, fretting increment caused by corrosion and synergy. Experimental results showed that the dissolution processes of three materials were accelerated significantly by fretting. The approximate removals of materials caused by synergy in saline solution are 31.6% for 316L stainless steel, 15.3% for Co-Cr-Mo alloy and 7.2% for Ti-6Al-4V alloy of total loss, respectively. The corrosion alone was a small percentage, just accounting for about 3% of total loss for three materials, The synergistic process of three materials was discussed based on three important stages, pure fretting, pure corrosion and synergy. The results suggested that both factors of materials and surface contact state should be considered simultaneously for the protection of three biomaterials under fretting corrosion conditions. The possible mechanism responsible for synergy between fretting and corrosion was also discussed.