工作温度对Pd-Ni合金薄膜电阻氢敏性能的影响

The Effect of Working Temperature on Hydrogen Sensor Performance Based on Pd-Ni Alloy Thin-films

目的 围绕氢气传感器在航天领域生命保障系统、氢燃料电池汽车领域能源供给系统等领域氢气泄露检测的迫切需求,针对在实际工况下工作温度对Pd-Ni合金薄膜电阻氢敏性能影响尚不清楚的问题,研究不同应用场景下工作温度对Pd-Ni合金氢敏电阻的灵敏度、响应-恢复时间以及回零特性影响。方法 将氢敏电阻分别置于80、90、100、110℃等不同工作温度,采用一定流量的动态气体测试方法,通入不同氢气浓度的测试气体,通过数据采集系统实时测量其电阻变化曲线,并评价其氢气敏感特性。结果 通过提高工作温度,在2%H_(2)/N_(2)和4%H_(2)/N_(2)氢气浓度下,110℃下的灵敏度相比80℃近线性降低约28%,80℃下2个浓度点的响应-恢复时间分别从16.5、12.9 s降低至110℃下的12.5、9.5 s,灵敏度的降低幅度与响应-恢复时间的加快幅度在100~110℃趋于平缓;在氮气气氛或空气气氛下,其零点电阻存在差异或未恢复至绝对零点,不影响氢气浓度测量的绝对值。结论 工作温度升高会降低氢敏灵敏度,但能提升其响应与恢复时间,也能加速其零点电阻的恢复,100~110℃工作温度下综合性能较佳。测试氢气浓度越高,其响应恢复时间越快。同时也发现“假零点”现象,可以指导在实际场景中如何有效更优使用。

Hydrogen sensors is urgently demanded for hydrogen leakage detection in the space field and energy supply system for hydrogen fuel cell vehicles.However,the effect of the working temperature on the hydrogen resistance properties of Pd-Ni alloy films is still not clear in different actual working conditions.Therefore,it is necessary to study the effect of working temperature on the sensitivity,response-recovery time and back-zero characteristics of the Pd-Ni alloy thin film resistance.The Pd-Ni alloy thin film resistance chip was prepared on the Al2O3 ceramic substrate by an ion-beam sputtering and a Lift-Off technique.After the heat treatment in a certain atmosphere and for a certain time,a printed circuit board of the packaging structure was placed at different operating temperatures of 80℃,90℃,100℃and 110℃.By using the dynamic gas test method,the test gas with different hydrogen concentration of a certain flow was measured through the data acquisition system,and the hydrogen sensitive characteristics were evaluated.The nitrogen zero-point resistor and hydrogen sensitivity response resistance values of Pd-Ni hydrogen sensitive resistance increased almost linearly with increasing temperature.The zero resistance was enhanced by 10Ωas the temperature increased by 10℃.At 2%and 4%,the response resistance increased by 9Ωfor every 10℃increase in temperature.At the concentrations of 2%H_(2)/N_(2) and 4%H_(2)/N_(2) hydrogen,the sensitivity at 110℃decreased nearly 28%compared to 80℃,and decreased nearly linearly with increasing the operating temperature.The sensitivity was 1.001%and 1.386%at the 2%concentration for the cases of 2%H_(2)/N_(2) and 4%H_(2)/N_(2),respectively;The sensitivity was 1.33%and 1.837%at the 4%concentration for the cases of 2%H_(2)/N_(2) and 4%H_(2)/N_(2),respectively.For the same hydrogen concentration,the response time and recovery time decreased rapidly initially and then tended to decrease slowly with further increasing the temperature.The response and recovery times were nearly equivalent under the same conditions,the response-recovery time at concentrations of 2%and 4%was reduced from 16.5 s,12.9 s at 80℃to 12.5 s,9.5 s at 110℃,respectively.As the hydrogen concentration increases,the response-recovery time increased by about 3-5 s at an operating temperature of 110℃,and the response-recovery times at concentrations of 2%and 4%were 12.48 s and 9.37 s,respectively.The decrease of sensitivity and the increase of response-recovery time entered the saturation region at 100-110℃.Considering the response-recovery time and sensitivity comprehensively,it showed good performance at the operating temperature of 90-100℃.The recovery of the zero-point resistance to the relative equilibrium platform at 80℃was 5-10 min slower compared to 110℃.At operating temperatures of 100℃and 110℃.The zero-point resistance initially decreased and then stabilized.In particular,the 110℃overshoot was particularly evident.The zero-point resistance of this working temperature range stabilized faster.The zero resistance was different or not restored to absolute zero in nitrogen or air atmosphere.The absolute value of the hydrogen concentration measurement was not affected.The working temperature would reduce the hydrogen sensitivity,but can improve its response-recovery time,also accelerate the recovery of its zero point resistance.The higher the hydrogen concentration,the faster the response-recovery time,Comprehensive performance of sensitivity,response-recovery time and zero speed was improved at 100℃.We also found"false zero"phenomenon,which can guide us to obtain the actual scene more effectively.