Contacts materials performances under break arc in automotive applications

New materials for electrical contacts have been developed recently, based o n AgFeOx, AgFeRe, AgZnO, and doped AgSnO2. The work described here aims at evaluating the material transfer characteristics, and the contact resistanc e behavior, of these materials under break are in automotive applications ( 14 V dc, 30-40 A). A comparison is made between these new materials and fou r reference materials: Ag, AgCdO, AgSnO2, and AgNi. Four of the new materials appear very promising: AgZnO, AgFeOx, doped AgSnO 2 io 6, and EMB8. These combine the good transfer performance of AgCdO in i nductive load, i.e., in long cathodic are, with that of AgSnO2 in resistive load, i.e., in short anodic are. For all materials, contact resistance is much higher in inductive load (7 m Omega) than in resistive load (1 m Omega ). An explanation of the different behaviors of these materials is attempte d by means of metallographic analysis.