Wear resistance of nitrogen-implanted steels

Abstract

The wear behaviour of various steels implanted with nitrogen was investigated by using a ball-on-disc tester under oscillating conditions without lubrication. The effect of nitrogen implantation on wear is highly dependent on the implanted steel composition; ferritic and austenitic stainless steels were examined and showed an improved wear resistance by more than two orders of magnitude, and even a martensitic stainless steel yielded an improvement of more than tenfold. Steels with a low chromium content (1−1.5 wt.%) showed less or no improvement. Corresponding measurements of microhardness indicated a marked increase in hardness (50%–300%) only for the stainless steels. For the CrNi steel X10 Cr Ni Ti 18 9 the dependence of the wear rate on the nominal ion dose was examined in the range (0.5–7) × 10 17 N + ions cm −2. A hundredfold decrease in wear rate was observed when the dose was increased from 2 × 10 17 to 3 × 10 17 N + ions cm −2. The dramatic decrease in the wear rate remained even after a wear depth of 2 μm.