中国微米纳米-PdCr薄膜电阻应变计研制及其高温应变敏感性能研究

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.     

薄膜应变计的横向效应及其影响因素

从电阻公式出发，利用金属的应变－电阻效应理论、弹性力学理论和薄膜的电导理论，导出了薄膜应变计的横向效应的表达式．分析了薄膜的厚度对薄膜应变计的横向效应的影响，并给出了实验结果与理论分析结果的对比．     

电阻应变计的温度效应及其消除方法

<正> 一、概述 电阻应变计是应变电测技术和应变式传感器必不可少的敏感元件。理想上,粘贴在试件上的应变计只响应施加在试件上的机械应变,而不受其它环境因素的影响。然而,同其它敏感元件一样,电阻应变计也并非尽善尽美。其一,应变计的电阻不仅随机械应变变化,而且随温度变化亦在变化(热输出);其二,应变计的灵敏系数,即电阻变化量与应变量之比本身也是温度的函数。这些温度效应如果不予以控制或消除,往往会带来显著的测量误差,有时甚至完全掩盖被测信号,而得出错误的结果。     

电阻应变计技术六十年（2）——电阻应变计敏感材料的发展（上）

敏感栅材料电阻应变计的关键元件，其性能将直接影响电阻应变计的各项特性，敏感材料的进展促进了电阻应变计的发展，本文主要介绍金属电阻合金，半导体，薄膜，厚膜等电阻应计敏感栅材料的进展，着重介绍各种金属电阻合金的主要性能。     

超低温应用的电阻应变计研究

介绍可应用于液氮至液氦超低温度和超导磁体系统的电阻应变计的研究工作，主要是对超低温电阻应变计进行热输出，灵敏系数对强磁场效应等工作特性的实验研究。     

一束常温应变计热零漂温补曲线族

一 概述热零漂温度补偿计算是相当复杂的.根据大量试验结果分析、比较,在一维稳定导热过程下,研制了拟合最佳的热零漂温补曲线——L曲线,将使问题简化.下面对有关曲线的几个因素进行分析.1.应变计通电后的热动态平衡电流流过应变计金属丝后,将引起焦耳热.为防止粘结剂因升温软化不能正常地传递信号,造成测量误差.不允许超过应变计主体发热与散热达平衡时的温度,应变计的热平衡与金属丝几何尺寸、环境条件、粘结剂底层和被测零件的导热系数有关.     

测定电阻应变计灵敏系数的一种方法

采用等强度梁、挠度计、并联电阻箱、电位差计等测定电阻应变计的灵敏系数是一种常用的方法。根据电桥的平衡条件建立了简单易懂的平衡方程，回避了桥臂阻值相对变化率的计算及电桥非线性输出等问题，正确计算了应变计的灵敏系数Ｋ。     

金属基Pt/ITO薄膜热电偶的制备

采用多层膜结构制备了金属基Pt/ITO薄膜热电偶,薄膜热电偶由Ni基合金基片、NiCrAlY过渡层、热生长Al2O3层、Al2O3绝缘层、Pt/ITO功能层和Al2O3保护层构成.静态标定结果表明:样品的平均塞贝克系数为107.45 μV/℃.测试温度可达到1000℃.时效处理可以有效提高薄膜热电偶的输出热电势.     

电阻应变计技术六十年（5）：———电阻应变计在传感器技术中的应用（上）

本文主要介绍电阻应变计在传感器中应用的一般情况,着重介绍目前应用最广的电阻应变式称重（测力）传感器和电阻应变计压力传感器的现状及展望。     

双层电阻栅SOI应变计的设计及其在煤矿的应用

设计了一种微熔结构的双层电阻栅SOI应变计,该应变计利用热生长氧化、光刻、刻蚀等工艺方法进行制作,解决了通常SOI应变计体电阻阻值小、易受污染的问题,提高了应变计的精度、绝缘性和工作稳定性。现场试验结果表明,利用该应变计制作的煤矿钻孔应力计测量数据准确,工作稳定可靠,适用于煤岩体应力监测。     

Effect of nitrogen doping on piezoresistive properties of a-Si x C y thin film strain gauges

In this study, the effect of nitrogen doping on piezoresistive properties of non-stoichiometric amorphous silicon carbide (a-Si _x C _y ) thin-film strain gauges was investigated. The films were prepared by plasma-enhanced chemical vapor deposition (PECVD) and the strain gauges were patterned by fabrication processes like conventional photolithography, metallization and reactive ion etching (RIE). The structure of the strain gauges consists of a a-Si _x C _y thin-film resistor with one Ti/Au electrical contact at each extreme of the resistor. In order to determine the piezoresistive properties, each strain gauge type was bonded near the clamped edge of a stainless steel cantilever beam and on the free edge calibrated weights were applied. The influence of the temperature on piezoresistive properties also was evaluated through the temperature coefficient of resistance (TCR) measurements from room temperature up to 250oC. It was observed that nitrogen doping increased the piezoresistive coefficient and TCR of a-Si _x C _y thin film strain gauges.     

功能-结构一体化NiCr/NiSi薄膜热电偶的制备

采用多层薄膜结构制备了NiCr/NiSi薄膜热电偶,该薄膜热电偶依次由Ni基超合金基片、NiCrAlY过渡层、Al2O3热氧化层、Al2O3绝缘层、NiCr/NiSi薄膜热电偶层以及Al2O3保护层构成.主要研究了热电偶层薄膜厚度和时效处理对热电偶性能的影响以及温度对Al2O3绝缘层绝缘性的影响.静态标定结果表明,热电...     

WO_3/Si-NPA复合薄膜的电容湿度传感性能研究

制备了基于硅纳米孔柱阵列(Si-NPA)的WO3/Si-NPA复合薄膜,并对其表面形貌进行了表征,研究了其电容湿度传感性能和基点电容的温度漂移。研究表明:WO3/Si-NPA继承了衬底Si-NPA规则的阵列结构的表面形貌特征,WO3的沉积形成了连续的WO3薄膜,WO3/Si-NPA是一种典型的纳米复合薄膜。室温下,WO3/Si-NPA的电容值随测试频率的增加而单调减小,但其灵敏度则在100 Hz时达到最大值。在此测试频率下,当环境的相对湿度从11%RH增加到95%RH时,元件的电容增量高达16 000%,显示WO3/Si-NPA对环境湿度有较高的灵敏度。同时,电容的湿度响应曲线显示出很好的线性。对其基点电容的温度稳定性研究表明:WO3/Si-NPA用作湿度传感的最佳工作温度区为15~50℃。     

传感器在监测隧道开挖对上方铁塔影响的应用

煤矿开采通常会导致铁塔基础发生沉降,塔体受力发生改变,对铁塔基础的沉降和铁塔的受力情况进行了监测.对铁塔受力的监测采用应变计与配套测试仪,并给出了应变计和沉降监测点的布设方案.监测结果表明:铁塔基础与地表的沉降都不大,铁塔的应力变化也不大.这说明隧道采用三台阶式开挖,对此铁塔的影响较小,可以保证铁塔的安全.     

Measurement of mechanical and thermal properties of co-sputtered WSi thin film for MEMS applications

In this study, mechanical and thermal properties of the co-sputtered tungsten silicide (WSi) thin film were evaluated to consider the possibility of its use in MEMS applications. WSi film was prepared by co-sputtering and basic micromachining processes, and its mechanical and thermal properties such as Young’s modulus, temperature coefficient of resistance (TCR), strain gauge factor, coefficient of thermal expansion (CTE) and thermal stress were studied. The measurement method was simple and efficient since only one test pattern was used for all measurements. At room temperature, the TCR, gauge factor, CTE and thermal stress were measured to be −670 ppm/°C, 2.8, 32 ppm/°C and 1.76 GPa, respectively. The dependence of these coefficients on temperature was also evaluated experimentally.     

Development of a flexible three-axial tactile sensor array for a robotic finger

In this paper, we propose a flexible three-axial tactile sensor array for measuring both normal and shear loads. The sensor array has 16 tactile sensor units based on piezoresistive strain gauge. It is constructed on a Kapton polyimide film using advanced polymer micromachining technologies. Thin metal strain gauges are embedded in polyimide to measure normal and shear loads, which are tested by applying forces from 0 to 1?N. The developed sensor unit had a hysteresis error of about 9% and repeatability error of about 1.31%. The sensor showed a good resulting image when pressed by a circle-shaped object with 10?N loads. The proposed flexible three-axial tactile sensor array can be applied in a curved or compliant surface that requires slip detection and flexibility, such as a robotic finger.     

Calibration of MEMS strain sensors fabricated on silicon: theory and experiments

A calibration technique for measuring MEM's strain sensor performance is presented. For resistance based sensors, calibration entails determining a relationship between change in resistance of the sensor and strain (the gauge factor). A modification to the standard calibration method employed for metal foil, resistance strain gauges is presented. The approach entails constructing two nearly identical test specimens: a specimen with the MEM's sensor mounted with adhesive and a specimen with a strain gauge on silicon mounted with adhesive. Data from the strain gauge specimen provide the basis for evaluating the strain at the sensor. Test data are presented which show that strain at the wafer is 52% to 55% of the strain applied to the specimen. A theoretical basis for this strain transfer relationship is presented. Finally, a dimensionless geometry factor, based on shear lag theory, is derived. As the sensor cross section (width and length) and thickness changes, the strain transfer between the specimen and sensor vary linearly with the geometry factor. This result emphasizes the importance in considering the overall sensor geometry when employing semiconductor strain gauges.     

氧化钒薄膜的有机溶胶-凝胶制备及电学性能研究

采用V2O5粉末为原料、苯甲醇、异丁醇为溶剂,通过溶胶-凝胶工艺在玻璃衬底上制备了用于非制冷红外探测器件热敏材料的氧化钒薄膜。利用四探针、椭偏仪、XPS等技术,分别测量所制备薄膜的电阻、厚度和化学成分,总结出前驱溶液配比、退火温度、膜厚等因素对薄膜电学性能的影响。结果表明,利用原料配比为V2O5：异丁醇：苯甲醇（g：mol：mol）=1：40：4的前驱溶液,所制备的厚度为440hm的氧化钒薄膜,并经500℃退火处理,显示出的电学性能最为理想,此时氧化钒薄膜的方阻为52．284kΩ（30℃）,TCR为-3．43％／K（30℃）。     

有关X射线测厚仪技术的研究

对西门子PLC（可编程控制器）在薄膜测厚仪上的应用进行了研究，并比较了传统的以工控机为核心的电控系统与以PLC为电控核心的系统的优缺点。详细介绍了测厚仪电控系统的组成和原理，同时对测厚数据的处理方法进行了说明。实践表明，该系统控制结构简单，有较高的运行效率和可靠性。整套装置已成功运行在聚丙烯双向拉伸薄膜生产线上。