Improvement of Arc Erosion Resistance of Ag–SnO₂ Contact Materials by Reducing Molten Pool Size

The splash of molten Ag under arc erosion is the major reason for the failure of Ag-based contact materials. Changing the size of the molten pool may manipulate the splash process and suppress the arc erosion. Herein, the size effect by fabricating a SnO₂ network with pores smaller than the typical Ag molten pool is investigated. Silver is subsequently infiltrated into the SnO₂ network to form Ag–SnO₂ interpenetrating contact materials. It is found that the SnO₂ network with small pore sizes separates the Ag matrix into smaller regions, reducing the melting volume. Compared with the particle-dispersed one, the interpenetrating composite decreases ≈90% mass loss and temperature rise, as well as provides superior microstructure stability. This finding demonstrates a promising way to improve the arc erosion resistance of contact materials by tailoring the size of molten pool, benefiting long-lifetime contact materials for smart grid applications.