Wear behavior and mechanism of plasma nitrided steel oscillating against a heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer.The influence of heat treatment on the mechanical properties of the alloy was evaluated.Furthermore,the wear debris was also examined to understand the wear mechanisms.The results show that a 220-230μm nitrided layer,which was harder than the substrate,was obtained on the steel surface.The tensile strength and hardness of the alloy are found to be significantly improved by the heat treatment associated with low impact toughness.The heat treatment of the alloy did not obviously decrease the friction coefficient of the nitrided steel-bronze couple.However,the wear loss of the nitrided steel increased when it mated with the treated bronze by a severe three-body abrasion.The nitrided steel was mainly damaged by fatigue spalling.Under plane contact conditions,the wear debris was mainly generated from the bronze part and can escape from the interface before being oxidized,leading to the phase structure of all the debris being copper rather than copper oxides. Wear behavior and mechanism of plasma nitrided steel oscillating against heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer. Influence the heat treatment on the mechanical properties of the alloy was.Furthermore, the wear debris was also examined to understand the wear mechanisms. The results show that a 220-230 μm nitrided layer, which was harder than the substrate, was obtained on the steel surface. tensile strength and hardness of the alloy are found to be significantly improved by the heat treatment associated with low impact toughness. the heat treatment of the alloy did not obviously decrease the friction coefficient of the nitrided steel-bronze couple. Host, the wear loss of the nitrided steel increased when it mated with the treated bronze by a severe three-body abrasion.The nitrided steel was mainly damaged by fatigue spalling.Under plane contact conditions, the wear debris was mainly generated from the bronze part and can escape from the interface before being oxidized, leading to the phase structure of all the debris being copper rather than copper oxides.