Formation and Evolution of Tribo-layer on Al_2O_3 and Al_2O_3-Based Ceramics in Sliding Against Si_3N_4 under Dry Sliding

摘要

Alumina (Al_2O_3) and Al_2O_3-based ceramics are candidate wear-resistant materials for many applications. In the past decades, the friction and wear behaviors of Al_2O_3 and Al_2O_3-based ceramics in dry sliding and lubricated conditions have been extensively investigated. In dry sliding, surface modification of Al_2O_3 and Al_2O_3-based ceramics at tribo-interface can be observed. In other words, the original surfaces of Al_2O_3 and Al_2O_3-based ceramics can be modified by friction and friction-induced material interaction (fracture, mechanical mixing, tribo-sintering) at the tribo-interface, and hence give birth to a tribo-layer. The formation and evolution of the tribo-layer on the worn surfaces of Al_2O_3 and Al_2O_3-based ceramics are the keys to understand the friction and wear behaviors of Al_2O_3 and Al_2O_3-based ceramics. This is conducted by scanning electron microscopy (SEM) observation and classification of the morphology and composition of the worn surfaces of Al_2O_3 and Al_2O_3-based ceramics at different sliding stages. The typical characteristics of the tribo-layers on the worn surfaces of Al_2O_3 and Al_2O_3-based ceramics in sliding against Si_3N_4 in a reciprocating motion are smooth surface with many interlinked cracks in morphology, mechanical mixing in chemical composition. The condition allowing the formation of the tribo-layer is briefly discussed.