Ag/Ti_2AlC复合材料的电弧侵蚀及退化机理

Arc Erosion and Degradation Mechanism of Ag/Ti_2AlC Composite

通过动态电弧放电实验深入研究了Ag/10TAC触头材料的抗电弧侵蚀机理。不均匀的电弧侵蚀使Ag/10TAC触头表面产生未受侵蚀、过渡和侵蚀3个特征区域。Ag微结构和化学组成变化归因于Ag熔化、气化、吸收O_2、Ag-O蒸气沉积和Ag-Al相互扩散。电弧侵蚀过程中Ti_2AlC微结构演变和氧化行为归因于Ti_2AlC的快速"分解-氧化"过程。触头表面的结构和功能变化导致了Ag/10TAC复合材料退化。

Ag-based contact is widely used in low-voltage switch(contactor,relay and breaker),which determines the safety and stability of the circuit.Toxic Ag/CdO goes against the development of environmentally friendly materials and will be excluded from future market.Ag/10%Ti2AlC(mass fraction,Ag/10TAC) composite shows excellent arc erosion resistance,and has the potential to replace Ag/CdO.Dynamic electric arc discharging experiment was performed on the Ag/10TAC contact surface to investigate its arc erosion mechanism.Inhomogeneous arc erosion generates three featured regions(unaffected,transitional,affected) on the contact surface.The various microstructure and chemical composition of Ag are attributed to the melting and vaporization of Ag,absorption of O2,deposition of Ag-O vapor,and interdiffusion of Ag-Al.The rapid "decomposition-oxidation" process of Ti2AlC accounts for the microstructure evolution and oxidation behavior of Ti2AlC during arc erosion.The changes of structure and function on the contact surface lead to the degradation of Ag/10 TAC composite.