柔性高温NiCr薄膜应变计研究

耐高温的NiCr薄膜应变计在航空、航天领域有广泛的需求。采用射频磁控溅射方法制备了NiCr薄膜,研究了溅射气压和衬底温度对NiCr薄膜电阻温度系数的影响规律,结果表明:当溅射气压为0.2 Pa,基片温度为400℃时,电阻温度系数最小为130.7×10^-6/℃。利用优化的工艺条件,在Hastelloy柔性合金衬底上制备了NiCr薄膜应变计,测试结果表明,所制备的NiCr薄膜应变计在各个温度下其电阻随着应变呈线性变化,其应变灵敏度(GF)因子随温度增加而增大,当温度超过200℃后,GF因子缓慢变化。温度为400℃时,GF因子达到3。实验得到的基于Hastelloy合金衬底的柔性薄膜应变计为高温应变测量提供了一种新的手段。

Study on flexible NiCr film strain gauge for high temperature applications

High temperature NiCr film strain gauge can be widely used in Aeronautics and Astronautics.NiCr thin films were prepared by RF sputtering method in this work.The influences of the sputtering pressure and substrate temperature on the temperature coefficients of resistance of NiCr films were investigated.The minimal temperature coefficients of resistance is 130.7×10^-6/℃when the sputtering pressure is 0.2 Pa and the substrate temperature is 400℃.The NiCr film strain gauge was prepared on Hastelloy tapes with the optimized process.The results show that the resistance of the NiCr film strain gauge is linear to the applied strain at each temperature.The GF factor increases with temperature and vary slowly when the temperature is above 200℃.The GF factor is 3 at 400℃.The flexible film strain gauges based on Hastelloy tapes provide a new way for strain measurement at high temperature.