Performance of different types of silver/tin oxide in regard to applications in automotive relays

Two types of automotive relays were used under different electrical loads (motor load, lamp load, resistive load) in order to compare different types of silver/tin oxide contact materials. Contact materials examined are all produced by means of the powder metallurgical technique, using additives in order to improve switching behaviour. It was found that Ag/SnO/sub 2/ materials using doped tin oxides are superior to the conventional types in regard to service life, i.e. resistance against material transfer and welding or adhering.