Nano-mechanical Degradation Behavior and Mechanism of Ag/Ti2SnC Composite Electrical Contact Materials During Arc Erosion

Silver-based electrical contact is a key material for structural-functional integration of low-voltage electrical equipment. In the actual service process, the maintenance of material composition-mechanical properties is the key to resist arc erosion and avoid premature failure of electrical contact materials. Therefore, elucidation of the degradation law of nano-mechanical properties at different arc erosion stages can further enrich the mechanism of electrical contact, which is of great significance for developing new electrical contact materials and advancing the innovation of low-voltage switch materials. In this study, Ag/Ti2SnC electrical contact material samples with different arc erosion times were designed, and nanoindentation techniques (static indentation, creep, continuous stiffness, NanoBlitz 3D indentation)were used to systematically analyze the nanomechanical properties of the section near the arc erosion area. Our results indicated a gradual degradation in the nano-mechanical properties of the samples with increasing arc erosion times, although the rate of this degradation appeared to decelerate over arc erosion times. During the early (1～100 times)and intermediate (100～1000 times)stages of arc erosion, the decline in the nano-mechanical properties was primarily due to the decomposition of Ti2SnC and limited surface oxidation. During the later stages of arc erosion (1000～6200 times), even though Ti2SnC damage from the surface to the inside, the formation of a surface oxidation layer and Ag-Sn interdiffusion behavior effectively slowed the mechanical property degradation, enabling Ag/Ti2SnC to maintain good arc erosion resistance. This study delivers an insightful nano-mechanical perspective on the arc erosion resistance of Ag/Ti2SnC electrical composite contact materials, providing a solid theoretical base for future material system continued design and optimization. © 2024 Chinese Mechanical Engineering Society. All rights reserved.