钛酸锶厚膜氧传感器的制备和性能研究

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1、摘要在低量施主掺杂可以提高元件灵敏度的基础上，重点研究了较高浓度施主掺杂对元件性能的影响，并对敏感机理进行了深入分析。利用正交实验，确定高浓度施主掺杂的最优配方，得到灵敏度和重复性均较好的样品。以此为基础，比较分析了贵金属催化剂n和Pd对元件性能的影响，结果表明Pt优于Pd，与理论计算相符；而元件的老化性能测试表明，相隔2个月，元件性能下降较明显，不利于实际应用。从制备工艺角度，考察了烧结温度对元件性能的影响，最佳烧结温度应在1250。C；比较分析了固相合成法和溶胶．凝胶法的优缺点，溶胶．凝胶法仍需继续改进。为了改善元件阻温特性，分别考察了La和Nb的掺杂量对于元件电阻的影响，进而

2、优化所得配方，得到最优配方为La10m01％，Nb4m01％。利用XRD和SEM等测试手段对元件进行了表征。XRD分析表明，溶胶．凝胶法和不同烧结温度的固相合成法均制备了具有纯净钙钛矿结构的样品，且溶胶凝胶法纯度更高；SEM二次电子图像表明，两种工艺制备的样品均具有疏松的表面形貌，但溶胶．凝胶法样品粒度较大，气孔率低；SEM背散射电子图像表明，n和Pd均匀的分布于样品表面，且Pd粒度均匀性优于n。关键词：SrTi03氧传感器施主掺杂烧结温度表面催化AbstractIIltllisdissertation,basingOiltheconclusionoflowquantitydono

3、rdopedcanimprovesensitivity,highquantitydonordopedwasresearchedemphatically,andthesensingmechanismalsobeanalyzeddeeply．FactortestmethodWaSemployedandanoptimaldopingquantitywasobtained,whichCanimprovethesensitivityandrepeatabilityobservably．BaSingonthisformula,theinfluenceofpreciousmetalPtandPd

4、舔surfacecatalystonthesample’SperformanceWaSanalyzed，andthetestdatashowedPtisbetterthanPd，whichWaSconsistentwiththeresultoftheoreticalcalculation；Thetestofagingpropertyshowedthatsample’Smainperformanceshaddecreasedobviouslyduringthepastedtwomonths，whichwasadversetoapplication·Fromtheperspective

5、ofpreparationtechnology,theinfluenceofsinteringtemperatureonsensitivityandresistance．temperaturecharacteristicWasresearched,andthebestsinteringtemperatureshouldbe1250"(2；ThecomparativeanalysisbetweensolidsynthesismethodandS01．GelmethodshowedthatSol—GelmethodhadmanyshortcomingsandfurtherworkWas

6、necessary．Inordertoimprovethesample’Sresistance-temperaturecharacteristic，theinfluenceofLaandNbonresistanceWasresearchedrespectively,andtheoptimalformulashouldbeLalOm01％，Nb4m01％．X．RayDiffraction(XRD)andScanningElectronMicroscope(SEM)Wasemployedtoanalyzethesamples．XRDshowedthatthedopedsamplespr

7、eparedbysolidsynthesismethodandSol—Gelmethodwerepureperovskitestructure，andthelatter吣better．SEMimagesindicatethatthesamples’surfacespreparedwiththosetwomethodswereloose，butformerwassmallerinthegrainsize．SEMbackscatteringimageshowedthatP