Self-Adaptive Formation of Tribo- Oxide Layer and Its Effect on the Friction and Wear of 40CrNiMoA Steel/Si3N4 Tribopair at 400 °C and 600 °C

The dynamics of friction and wear of a contact pair consisting of 40CrNiMoA steel/Si3N4 ball were determined at 400 °C and 600 °C respectively with a variable of sliding duration in the air. The results showed that friction instability predominantly occurred at the initial running-in period, while an exponential reduction in the specific wear-rate was observed at both temperatures. The temperature exerts greater influence on the spontaneous formation of a tribo-oxide layer on the rubbing contact, and the deleterious effects of wear at 600 °C. Friction-induced hardening accounted for improved wear resistance behavior along with the sliding extending. The influence of temperature on the structural alteration and elementalmigration at the rubbing surface was further discussed based on the mechanics of the tribo-induced layer.