| With the rapid development of aerospace industry in China,the traditional metal wire/foil strain gauges and semiconductor strain gauges are more and more difficult to meet the requirements of hypersonic wind tunnel.The thesis aims to develop a strain gauge with small size,high gauge factor（GF）and low temperature coefficient of resistance（TCR）,and apply it to the microstrain measurement of hypersonic wind tunnel model,which is of great significance for the development of hypersonic technology in China.The gauge factor of thick film resistor（TFR）is higher than that of metal strain gauge,and the temperature stability is higher than that of semiconductor strain gauge.TFR has excellent comprehensive performance and wide temperature range,which make it has the potential to be used in hypersonic wind tunnel test.Based on the above advantages,a TFR based on fluorophlogopite substrate was developed,and the feasibility of forming a Wheatstone full bridge sensor by TFRs was verified.（1）The preparation process of TFRs was explored,and the parameters of screen printing and sintering of TFRs were optimized.The structural design of TFRs based on fluorophlogopite substrate was completed from three aspects: the selection of electronic paste,the determination of substrate thickness and the design of resistor size.Through experiments,it was determined that the substrate thickness of TFRs was 0.1 mm and the effective resistor size was 1 mm × 1 mm.（2）The performance changes of TFRs prepared by two kinds of Xi’an Hongxing R-2200 ruthenium series resistor pastes at different sintering temperatures were studied experimentally.The results showed that R-2214 resistor paste with a sheet resistivity of10 kΩ/□ had higher GF and TCR than R-2213 resistor paste with a sheet resistivity of 1kΩ/□.When the sintering temperature was 850 ℃,the temperature stability of R-2213 TFRs was the best,its GF and TCR were 5.42 and-13.22 ppm/℃.When the sintering temperature was 800 ℃,the gauge factor of R-2214 TFRs was the highest,its GF and TCR were 8.14 and 95.79 ppm/℃.（3）The effect of sintering time on the performance of TFRs prepared by R-2214 resistor paste was analyzed.The results showed that the increase of sintering time was helpful to improve the performance of TFRs.When the sintering time increased from 10 min to 180 min,the GF of R-2214 TFRs increased by 9.25%,and the TCR decreased by45.03%.（4）The sensitivity of Wheatstone full bridge composed of TFRs based on fluorophlogopite substrate was explored experimentally.The results showed that the sensitivity of Wheatstone full bridge in the ipsilateral plane was just about 2.The sensitivity of the Wheatstone bridge in the opposite plane was similar to the gauge factor of TFRs themselves. |
