Long Time Stability of Pb-Free Sn-9Ze Elements for AC-Low Voltage Fuse Performance

摘要

In order to evaluate the stability in long time for the performance of AC-low voltage fuses, this study aimed to measure the changes of the specific resistivity, specific heat and thermal conductivity due to the microstructure-change, using a diffusion couple consisting of the Sn-9Zn fuse element and Cu-connector which are exposed at 443 K for 7.2 ks. The reaction area with the thickness of 5 μm consisting of Sn, Cu and Zn phases, was formed at its interface. The values in their properties were increased due to microstructure-change caused by the diffusion. The equations for the estimation of their values could be represented as a function of temperature. The good stability in long time for the un-melt down performance at 210 A of electric current, was confirmed by three-dimensional voltage and temperature calculations on fuse elements after diffusion.