Abstract
Cr-Cu-Te alloy prepared by PM method showed better performance than conventional Cr-Cu alloy for electric-contacts of vacuum insulated switches. In order to improve insulation performance by decreasing vaporization of Te, optimization of Te addition was conducted.
As the performance of Cr-Cu-Te is determined by the bonding strength between Cr particles and Cu matrix, the boundary layer between Cr and Cu was investigated by TEM, STEM and EDS. The boundary layer contained Cu, Cr and Te, and is considered to be multiple ternary intermetallic compounds.
Based upon an assumption that the bonding strength depends on area of the boundaries and natures of the boundary, those two factors were changed by using 3 different sizes of Cr particles and amount of Te addition. In case of coarse (>53 μm) Cr particles, even 0.05% addition of Te showed the effect as significant as that of 0.1 or 0.2% addition, while that of fine (22-45 μm) Cr particles requires more than 0.1%.
Possible mechanisms of the boundary layer and the gap were discussed.
