Mechanical and chemical properties of tantalum-implanted steels

The surface mechanical and chemical properties of tantalum-implanted AISI 52100, AISI M50 and AISI 9310 steels and pure iron were investigated. Sputter Auger profiles of pure iron indicate significant carbon incorporation during implantation. For AISI 52100 steel the unlubricated kinetic coefficient of friction is reduced from 0.6 to 0.38, the load-carrying capacity is increased and the pitting potential in a 0.01 M NaCl solution is increased by 510 mV. The corrosion resistance of tantalum-implanted AISI M50 steel in 0.5 M H₂SO₄ is equal to that of high dose chromium implantation. The rolling contact fatigue life is significantly improved for tantalum-implanted AISI M50 steel and a 24% increase in load-carrying capacity is measured for Ryder gear scuffing tests on tantalum-implanted AISI 9310 steel. The mechanism producing the improvements in corrosion resistance is thought to be selective dissolution of iron with the formation of a tantalum-rich passive oxide film on the surface, while friction reduction is at least partly responsible for improving the wear properties.