Kovar合金引脚的热电效应对压力敏感芯体输出的影响

Influence of thermoelectric effect of Kovar alloy pin on output of pressure sensitive core

可伐(Kovar)合金与玻璃、陶瓷等被封接材料的热膨胀系数相近,在航空、航天、军工所使用的传感器领域主要用作压力敏感芯体的引脚。航空、航天、军工领域所使用的传感器一般都有低输出漂移量的需求,但是在实际使用过程中,部分传感器上电后会存在较大输出漂移的现象,可伐合金引脚的热电效应就是导致这种现象的原因之一。测量可伐合金引脚热电势-温度变化曲线,计算出可伐合金引脚的Seebeck系数;分析不同引脚上产生的热电势对压力敏感芯体输出造成的影响,并给出了详细的计算公式;讨论了几种设计要点,可以通过更改可伐合金引脚的布局、增加热传递的距离、增加隔热层等手段削弱可伐合金引脚热电效应造成的影响。

The thermal expansion coefficient of Kovar alloy is similar to that of glass, ceramic and other sealed materials. Kovar alloy is mainly used as the pin of pressure sensitive core in the field of sensors used by aviation, aerospace and military industry. The sensors used in aviation, aerospace and military fields generally have a low output drift demand, but in the actual use of the process, some sensors after power-on will have a large output drift phenomenon, the thermoelectric effect of the Kovar alloy pin is one of the reasons for this phenomenon;The thermoelectric potential-temperature curve of the Kovar alloy pin was measured, and the Seebeck coefficient of the Kovar alloy pin was calculated. The influence of thermoelectric potential on the output of pressure sensitive core is analyzed, and the detailed calculation formula is given. Several design points are discussed. The thermoelectric effect of the Kovar alloy pin can be reduced by changing the layout of the Kovar alloy pin, increasing the heat transfer distance, increasing the insulation layer and so on.