电极对PTC热敏电阻老化性能的影响

Influence of Electrodes on Aging Performance of PTC Thermistor

为探究电极因素对PTC热敏电阻老化性能的影响,分别对烧渗Al电极,烧渗Ag-Zn电极和烧渗Ni电极等三种类型的PTC热敏电阻元件进行了老化试验。结果显示:烧渗Ag-Zn电极的元件有较好的老化性能,阻值变化率?R/R≈–4%,电流冲击失效率≈0。从材料热力学和电极的电化学两方面,对该老化特性进行了分析,表明材料热膨胀失配和电极电化学不稳定性,是电极影响元件老化性能的两大因素。

For study on the influences of electrodes on aging performances of PTC thermistors, the three kind of PTC thermistors which were freezed on Al electrode, Ag-Zn electrode and Ni electrode, respectively, were investigated. Experiment results indicate that the ones with Ag-Zn electrode possess better ageing performance (Their resistance value variance rate is about –4%, surge current failure rate is nearly 0). The effects of electrodes on aging performance of PTC components were researched in the material thermodynamics field and electrode galvano-chemistry field, respectively. Obteined results show that materials’ heat expansion mismatch and its instability in electrode galvano-chemistry field are two important factors of affecting the aging performance.