Study on the modification mechanisms of TiO 2 and Bi 2 O 3 doping in AgSnO 2 contacts on arc erosion characteristics

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Abstract This study investigates the distinct modification mechanisms of TiO 2 and Bi 2 O 3 doping on the arc erosion behavior of AgSnO 2 electrical contacts via a two-dimensional magnetohydrodynamic simulation and experimental validation. The maximum molten pool volume and the quasi-steady average arc temperature were calculated as primary and secondary indicators respectively. The influences of the additives and their concentrations on the erosion were analyzed by linking with the intrinsic physical properties. Results reveal opposing effects on arc temperature: TiO 2 , which has high melting and boiling points, remains solid, stabilizes the arc, enhances heat conduction, and reduces quasi-steady average arc temperature by 1053 K at 3% doping. Conversely, Bi 2 O 3 , with lower melting and boiling points, may vaporize, potentially increases plasma radiative conductivity, and is associated with a rise in quasi-steady average arc temperature by 714 K at 3% doping. Regarding erosion, TiO 2 more effectively reduces molten pool volume—achieving a 20.3% reduction at the anode with 3% doping—by increasing melt viscosity and providing physical constraint, whereas Bi 2 O 3 offers weaker inhibition with a 16.1% reduction, which may be partly due to vapor-enhanced heat input and lack of solid-state confinement. Simulations also confirm asymmetric erosion, with anode pool volume ∼30% larger than the cathode’s, attributed to differential energy deposition and sputtering. It is concluded that TiO 2 is superior to Bi 2 O 3 for enhancing arc erosion resistance in AgSnO 2 contacts, and an asymmetric doping strategy with a higher additive proportion at the anode is recommended. This work provides a mechanistic basis for designing durable AgSnO 2 contact materials.

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