Enhancement of wear resistance of AISI 1045 steel by a two-step plasma treatment

A two-step plasma treatment (TSPT) combining plasma nitrocarburizing (PNC) and plasma nitriding (PN) was developed for AISI 1045 steel, and also compared with PNC-only and PN-only treatment. The microstructure and related properties were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers hardness tester and pin-on-disk tribotester. The results showed that TSPT treated specimens exhibited highest surface hardness, lowest friction coefficient of 0.35, decreased 37.5% and 18.6% comparing with PN and PNC, and lowest wear rate of 3.34 × 10−5mm3·Nm−1, decreased 75.4% and 55.7% comparing with PN and PNC. In other words, TSPT treatment could bring out significant enhancement of wear resistance, which is more than 4 times better than that of PN and more than double than that of PNC, due to the increased compound layer thickness, optimized phase constituents and decreased friction coefficient.