【作者】 张宗阳；

【导师】 刘胜；

【作者基本信息】 华中科技大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 压力传感器在各个行业各个领域都有着广泛的应用，是传感器大家族中需求量最大的品种。然而目前市场上的各种压力传感器都存在着这样或那样的缺点，无法满足不同应用领域的实际需求。针对当前主流压力传感器技术存在的不足，结合国内外行业发展状况，本文提出了两种非传统的基于厚膜工艺的不锈钢压力传感器，并对其进行研究。第一种是在430不锈钢弹性体上烧结厚膜电阻应变片制作不锈铁压力传感器。测试所需材料参数，借助于有限元法设计厚膜不锈钢压力传感器的结构和制造工艺，评估其的综合性能和可靠性。第二种是采用外延沉积技术制作半导体应变片，并将其通过厚膜工艺烧结在17-4PH不锈钢弹性体上制成不锈钢压力传感器，评估其主要性能指标；研究粘接剂材料特性和微观结构对传感器输出特性的影响。主要研究内容包括：（1）采用纳米压痕连续刚度法测试430不锈钢基片上介质层的力学性能，结果显示，其平均杨氏模量为126.56GPa，平均硬度为8.364GPa。测试厚膜电阻的性能参数，评估其作为力传感器应变片的可行性。厚膜电阻的应变系数约为10.2，电流噪声约为20dB，在40～125℃的温度系数小于230ppm/K，在125～220℃的温度系数小于250ppm/K。（2）自由落体试验和热冲击试验验证介质层和430不锈钢基片粘接的可靠性；微观结构分析表明不锈钢、介质层和厚膜电阻层在材料成分上是兼容的，证实了制作厚膜不锈钢压力传感器的可行性。（3）采用有限元模拟，确定介质层的厚度与在额定载荷下厚膜电阻在介质层-不锈钢弹性体上的印烧位置。模拟计算厚膜电阻的自热效应、介质层与不锈钢的热胀系数失配产生的热应力对厚膜不锈钢压力传感器输出特性和可靠性的影响，并提出相应的改进方法。（4）设计厚膜应变片式不锈钢压力传感器工艺流程，制作样品，评估其性能指标。该传感器在40～125℃的温漂小于2.5%，与精度相关的参数误差（线性度、迟滞和重复性误差）都在0.15%以内；在125～220℃范围内，该传感器的温漂不高于2.85%，与精度相关的参数误差都在0.3%以内。（5）采用外延沉积技术制造半导体应变片以提高其阻值一致性。借助于厚膜技术，用微熔玻璃作为粘接材料将半导体应变片烧结到17-4PH不锈钢弹性体上制作不锈钢压力传感器。该传感器在125℃的迟滞和重复性误差分别低于0.05%和0.12%，几乎完全等同于其在常温下的性能，表明微熔玻璃粘片工艺提高了传感器的高温性能。进一步的实验显示粘接剂微观结构缺陷会使应变片式压力传感器的迟滞和重复性误差恶化。更多还原

【Abstract】 Pressure sensors, with demand being the largest among all sensors, are widely used invarious industry fields. However, most of the products currently available are not perfectenough to meet the requirements of some specific occasions.Taking the technical weaknesses of mainstream pressure sensors and the developmentstages at home and abroad into consideration, two types non-traditional steel pressuresensors based on thick film technology are proposed and investigated in this thesis. First,thick film resistors (TFRs) on430stainless steel substrate for strain sensor applicationsare investigated. The material parameters related to the sensors are tested and the steelpressure sensors are designed and manufactured by using finite element method (FEM).Second, a novel pressure sensor design using epitaxial silicon strain gages bonded on17-4PH stainless steel diaphragm based on thick film technology is also proposed andevaluated, and effects of the microstructure of the adhesive on the sensor performances areanalyzed. The main research efforts are as follows:(1) Nanoindentation test with the continuous stiffness method (CSM) is conductedon the dielectric-on-430steel substrate to obtain its mechanical properties. Test resultsshow that the average elastic modulus of the dielectric-on-steel substrate is126.56GPaand the average hardness is8.364GPa. The performance parameters of the thick filmresistors (TFRs) are measured to verify their feasibility as strain gages for pressure orforce sensors. Results show that gauge factor (GF) and noise indices (NI) of TFRs are10.2and20dB, respectively. And the temperature coefficients of resistivity (TCRs) are230ppm/K (40～125°C) and250ppm/K (125～220°C).(2) Reliable bonding between the dielectric and430steel substrate is confirmed byfree fall test and thermal shock test. Microstructure analysis shows the compatibility ofTFRs and the dielectric on steel substrate, which indicates the feasibility ofmanufacturing thick film steel pressure sensors.(3) The thickness of the dielectric and the positions of TFRs on thedielectric-on-steel are obtained by FEM. Effects of the thermal stresses and the self-heating of TFRs on the performance and reliability of the steel pressure sensors areevaluated, and the corresponding improvement measures are proposed.(4) Thick film based steel pressure sensors are designed and manufactured, and theperformance characteristics are evaluated. Test results show that the temperature driftsof the sensors are less than2.5%full scale (FS), and the accuracy-related parametererrors are no more than0.15%FS from40°C to125°C. And from125°C to220°C,the temperature drifts of the sensors are less than2.85%FS, and the accuracy-relatedparameter errors are no more than0.3%FS.(5) The strain gages with uniform resistance are obtained by growing an epi-siliconlayer on a single crystal silicon wafer using epitaxial deposition technique rather thanconventional photolithography and etching techniques. The inorganic glass frits ratherthan organic adhesives are used as the bonding material between the strain gages and the17-4PH SS diaphragm. Results show that the hysteresis and repeatability errors of sensorsare less than0.05%FS and0.12%FS at125°C, respectively, which are almost equal tothose at room temperature, showing the robust high temperature stability. Experimentalresults show that the defects in the organic adhesive greatly deteriorate the hysteresis andrepeatability errors of the sensors.更多还原