新型 Ti₂Cd 增强银基电触头材料的制备及抗电弧侵蚀特性

Due to their outstanding electrical contact properties, Cd⁃containing silver⁃ matrix electrical contact materials can meet the requirements of high stability and long life for military defense and aerospace applications. In order to further reduce the Cd content under the premise of meeting the high-performance requirements, in this study, high-purity intermediate Ti₂ Cd powder of MAX phase (Ti₂ CdC) was synthesized with a pressureless technique and then applied to reinforce the Ag matrix. The Cd content of the as-prepared Ag / Ti₂ Cd composites was actually reduced by 38.31% compared with conventional Ag / CdO material. Based on the systematic study of the effect of heat treatment temperature on the physical phase, morphology, interface and comprehensive physical properties of Ag / Ti₂ Cd composites, the preferred samples (heat treated at 400 ° C for 1 h) showed high density (97. 77%), low resistivity (2. 34 μΩ · cm), moderate hardness (90. 8HV), high tensile strength (189.9 MPa), and exhibited good electrical contact performance after 40000 cycles of arc discharging under severe conditions (DC 28 V / 20 A) . The results of microscopic morphological evolution, phase change and elemental distribution of the electrical contact surface show that the combination of high stability of Ti₂ Cd reinforcing phase, good interfacial bonding with Ag matrix and improved melt pool viscosity in the primary stage of arc erosion, results in low and stable contact resistance (average value 13. 20 mΩ) and welding force (average value 0. 6 N), low fluctuation of static force (2.2—2.5 N) . The decomposition and absorption energy of Ti₂ Cd and the arc extinguishing effect of Cd vapor are the main reasons for the stable arcing energy and arcing time of electric contacts in the late stage of arc erosion.