Effect of SnO2 particulate characteristics on mechanical properties of Ag/SnO2 electrical contact materials

Abstract

The particulate characteristics (shape, size, and mass fraction) of SnO₂ particles in Ag/SnO₂ electrical contact materials govern their complex mechanical response, which cannot be fully characterized through conventional experimental methods. Here, finite element modeling was employed to unravel the intrinsic coupling between the matrix and particles in Ag/SnO₂. Representative volume element (RVE) models were constructed based on experimentally derived microstructural data, enabling systematic analysis of deformation mechanisms, interfacial debonding phenomena, and crack propagation pathways under varying geometrical parameters and mass fractions. Key findings demonstrate that short prismatic (SP) particles optimize the strength-ductility balance, whereas long prismatic (LP) particles enhance load transfer at the expense of plasticity. Striking a balance between the intricacy of particle shape complexity and dimensional control emerged as a critical strategy for mechanical performance enhancement. The progressive damage evolution was simulated by integrating cohesive zone modeling with ductile fracture criteria. The crack formation mechanism was identified to be caused by interfacial debonding-induced microvoid nucleation and coalescence. Crack extension was effectively impeded by SP particles, correlating with improved material elongation. Therefore, a computational framework was established for elucidating microstructure-property relationships in particle-reinforced electrical contact materials.