Interfacial thermal stress relief in Ag–SnO2 composites by in situ formation of CuO nanoparticles additive on SnO2

Abstract

Interfacial thermal stress is induced by the large differences in the thermal expand coefficients between SnO2 and the Ag matrix in the Ag–SnO2 composite, resulting in the initiation and propagation of microcracks during service. In this study, the in situ formation of CuO nanoparticle additive on SnO2 reinforcements was used to relieve interfacial thermal stress in Ag–SnO2 composites and the electrical contact performances were systematically evaluated. The CuO nanoparticles formed at the interface between SnO2 and the Ag matrix effectively inhibited the initiation and propagation of cracks in the Ag–SnO2 material during the arc erosion process. The arc erosion resistance of the prepared material was significantly improved, accompanied by a significant decrease in the arc energy. The thermal stress concentrated around the SnO2 phase was noticeably relieved by the CuO nanoparticles formed in situ, which is superior to that of the general CuO additive. Moreover, the electrical conductivity of the Ag–CuO@SnO2 composite increased by 41% and the contact resistance was quite stable. This work provides theoretical implications and serves as an application reference for the development of high-performance electrical contact materials.