【作者】 郑龙华；

【导师】 李箭； 蒲健；

【作者基本信息】 华中科技大学 ， 材料学， 2009， 硕士

【摘要】 汽车尾气氧传感器广泛运用于电喷汽车三元催化系统中,用于检测尾气中氧气含量,并通过反馈控制实现发动机保持在14.7的最佳空燃比以最优工况。由于日渐严格的环保法规,汽车尾气氧传感器有着广阔的市场前景。本课题主要研究了平板式汽车尾气氧传感器的制备工艺,为了制备出性能符合标准的氧传感器,对工艺进行了研究与优化:表征了实验中用到的原料,用粒度分析仪、SEM及XRD等方法对粉体原料进行了分析。采用流延法、丝网印刷法和层压成型法制备了氧传感器素体;采用流延法制备基体薄片,丝网印刷法制备功能层,层压成型法完成多层基体组装;研究了流延、丝网印刷成膜以及层压成型的规律;详细分析了影响多道工艺质量的各种因素。研究了氧传感器的整体共烧结过程,在此基础上制定了两段式烧结法工艺路线。设计了拥有更优良烧结性能的新型氧传感器绝缘层材料。研究了氧传感器热应力损伤与破坏的机理;探究了增强氧传感器抗热震性能的途径。探索了可能的氧传感器加热电极金属替代材料,研究了其长期可靠性。对制备完成的氧传感器样本进行了测试,将测试结果与商用标准进行了对比,认为其性能符合实际使用要求。更多还原

【Abstract】 Planar automotive exhaust gas sensors widely applied in the three-way catalyst system are used to detect oxygen in exhaust gas and control the air/fuel ratio to stay at the stoichiometric point which is 14.7 to make ture the engines work at the best condition. Because of the stricter vehicle emission control laws day by day, the worldwide market will be remarkably extended.In this paper, the fabrication technique for planar exhaust gas sensors has been explored. In order to fabricate exhaust gas sensors with better performance, we investigated and optimized the following techniques:Materials for experiments are researched. The particle size and its distribution were measured with a Laser Particle Size (LPS) analyzer. The surface morphology and microstructure of powders were examined with Scanning Electron Microscope(SEM). Desirable phases were identified with X-ray diffractioner.Tape casting, screen-printing and lamination processes, simple and cost-effective techniques, were used to fabricate the exhaust gas sensors. Support was prepared by tape casting. Functional thin films were prepared by screen-printing. Final assembly was prepared by lamination. Several experiments were conducted to optimize the processing parameters of tape casting, screen-printing and lamination. The influence of the parameters on the quality of production process was discussed.The support/functional films multilayer ceramic green bodies sintering processes were researched. Factors resulting in shrinking were analyzed and discussed and the two-stage sintering process was explored and optimized.The novel insulation materials with better sintering performance was investigated. The thermal shock behavior of exhaust gas sensors was researched, the methods of improvement the thermal shock resistance of exhaust gas sensors were put forward. The feasibility of novel metal which could instead of platinμm used in the heating electrode was reseached, the long time reliability of the novel heating electrode was checked.The responses of the samples of final produtions were mearsured in a engine emission atmosphere, and the electrical output signal was analyzed. After all these checking, the exhaust gas sensors productioned by ourself are believed as good value production.更多还原