Tribological Studies of Ion-Implanted Steel Constituents Using an Oscillating Pin-on-Disk Wear Tester

Wear tests of ferrite (pure α-Fe) and austenite (AISI 304 stainless steel) implanted with nitrogen have been conducted using a unique oscillating pin-on-disk test machine. The results show that nitrogen implantation at elevated temperatures to high doses dramatically improves the adhesive wear resistance of ferrite and the critical load at which the wear mechanism changes from mild to severe adhesive wear for austenite. The wear resistance of nitrogen implanted ferrite is determined by the nitride formed. Ranked from most to least wear resistant the nitrides observed are γ’-Fe₄N, ε-Fe₃N, and ζ-Fe₂N. No evidence of nitride break-up and attendant nitrogen migration during wear testing is found. Nitrogen does diffuse into both ferrite and austenite rapidly when they are implanted at an elevated temperature and this enhances their wear resistances.