For aerospace and nuclear fields at high temperatures,strain gauge that can be used in various hot sections is in urgent need to provide accurate measurement of strain,fatigue and other structural parameters.PdCr thin film resistive strain gauges were fabricated on the nickel-based superalloy substrate.NiCrAlY alloy as a buffer layer was first deposited to enhance the adhesion of the following layers,YSZ/Al2O3 as a composite insulating layer was then prepared to obtain the required electric insulation,then PdCr thin film as the sensing material was sputtered,and patterned using the metal mask,finally Al2O3 thin film layer as a high temperature protective overcoat was deposited.The gauge factor,apparent strain and drift strain of PdCr thin film strain gauge at different temperatures were investigated.The results indicated that resistance value of PdCr thin film strain gauge showed an excellent linear relationship with strain at different temperatures.Gauge factor(GF)of PdCr thin film strain was measured to be 1.40 at room temperature;At 800 ℃,apparent strain sensitivity is 127 με/℃,and the resistance value of the strain gauge insignificantly decreased with time and the drift strain was about 1 800 με/hr.Gauge factor at 800 ℃ was 1.41,almost the same as that of room temperature.The reproducibility and lifetime of PdCr thin film strain gauge were also evaluated.It showed that the repeatable measurement error was 5.71%,and lifetime was over 10 hours.%在航空航天以及核电领域中,准确测量高温部件的应变、疲劳等结构参数十分重要,对满足高温应用环境的高温应变计需求非常迫切.在镍基合金基底上研制了PdCr薄膜电阻应变计,依次在基片上沉积NiCrAlY作为过渡层来增强附着性,沉积YSZ/Al2O3作为复合绝缘层满足绝缘性需求,溅射PdCr合金作为应变敏感层,并采用金属掩模对PdCr敏感层进行图形化,最后沉积Al2O3薄膜层作为高温保护层,并对PdCr薄膜应变计的应变敏感系数(GF)以及高温环境下的表观应变、漂移应变等性能进行了表征.结果表明,不同温度下PdCr薄膜应变计的电阻值随应变呈良好的线性关系;在常温下,其应变敏感系数为1.40;在800 ℃时,应变计的表观应变系数127 με/℃.应变计的电阻值随时间线性减小,导致的漂移应变约为1 800 με/hr,应变敏感系数为1.41.同时,对制备的PdCr薄膜应变计进行了可靠性评估和寿命评估.结果表明,其重复性测量误差约为5.71%,工作寿命超过10 h.
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