| In this dissertation, basing on the conclusion of low quantity donor doped can improve sensitivity, high quantity donor doped was researched emphatically, and the sensing mechanism also be analyzed deeply. Factor test method was employed and an optimal doping quantity was obtained, which can improve the sensitivity and repeatability observably. Basing on this formula, the influence of precious metal Pt and Pd as surface catalyst on the sample's performance was analyzed, and the test data showed Pt is better than Pd, which was consistent with the result of theoretical calculation; The test of aging property showed that sample's main performances had decreased obviously during the pasted two months, which was adverse to application. From the perspective of preparation technology, the influence of sintering temperature on sensitivity and resistance-temperature characteristic was researched, and the best sintering temperature should be 1250℃; The comparative analysis between solid synthesis method and Sol-Gel method showed that Sol-Gel method had many shortcomings and further work was necessary. In order to improve the sample's resistance-temperature characteristic, the influence of La and Nb on resistance was researched respectively, and the optimal formula should be La 10mol%,Nb 4mol%.X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) was employed to analyze the samples. XRD showed that the doped samples prepared by solid synthesis method and Sol-Gel method were pure perovskite structure, and the latter was better. SEM images indicate that the samples'surfaces prepared with those two methods were loose, but former was smaller in the grain size. SEM backscattering image showed that Pt and Pd distributed on the samples surface uniformly, and the latter's uniformity of particle size was better. |
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