Silver-tin oxide materials used in low voltage switching devices

Seven AgSnO₂ contact materials produced by powder metallurgy were tested on accelerated test machines and on contactors. The performance of these materials is compared to those of an AgCdO material. All these materials have in common the fact that their composition is similar (88/12), and that they are all prepared using powder metallurgy. The weld and erosion tests were orientated towards applications in contactors whose nominal current is over 100 A. The results of these tests show that, when used with high currents, AgSnO ₂ materials do not normally increase the life expectancy of the equipment concerned. However, their excellent antiwelding characteristics in dynamic operation ensure that they provide increased operational safety