Synergistic effect of fretting wear and sliding wear of Co-alloy and Ti-alloy in Hanks' solution

In corrosive wear authors have previously considered the synergistic effect as the dynamic corrosion, where the fresh surface was exposed in solution during sliding. In this paper the synergistic effect was more discussed. The mechanical assisted corrosion, related to the dynamic corrosion, and corrosion assisted mechanical wear was introduced. Two corrosive wear tests, fretting wear test with slip amplitude below 80 μm and reciprocating sliding wear test with 10 mm stroke, were carried out for biomaterials of Co-29Cr-6Mo alloy and Ti-6Al-4V alloy against Al2O3 ball in quasi-body fluid, Hanks' solution. SUS304 stainless steel was also tested as a reference material. Co-alloy was newly developed as a new Ni free bio-metal. Ti-alloy revealed good fretting resistance, but not for the sliding wear due to the abrasion by roughened Al2O3. Co-alloy showed the insensitive property on slip amplitude and shows the good wear resistance over 100 μm. The synergy effect appeared much stronger in the fretting than in the sliding wear. The chemically assisted mechanical wear Wcm was positive in the fretting, but it was negative for Co-alloy and SUS304 steel in the sliding wear.