Optimization of silver tin oxide chemistry to enhance electrical performance in a.c. application

The addition of copper oxide (0.37-0.53%) to silver tin oxide based material substantially improved the electrical performance in a.c. application. The erosion behavior of the material was directly related to the level of copper oxide in the silver tin oxide based materials. The investigation was undertaken to correlate the changes in contact performance as the copper oxide additive varied. Performance changes and physical characteristics of each material, such as formability (tensile properties), contact resistance and contact material erosion (arc erosion) were evaluated. The resistance to arc erosion of silver tin oxide based material containing 0.37-0.53% copper oxide by weight was superior in comparison to other silver tin oxide based materials containing 0.025%, 0.065% and 0.96% of copper oxide. In addition changes in electrical resistance were not dependent on the chemistry of each material. The results suggested copper oxide addition of 0.37-0.53% by weight was the chief reason silver tin oxide based materials out-performed other doped silver tin oxide based material under the same test conditions.