Preparation Of Electrode And Research On Its Performance Of Zirconia Oxygen Sensors

Zirconia oxygen sensors can monitor and control combustion ambiences, so they have been widely applied to the fields such as National Defense Science and technology, transportation, metallurgical chemical, medical, food brewing, family appliances. Be established in its research status at home and abroad, this paper systematically investigates the key technology such as the preparation of electrode slurry, sintering process and characterization of electrode.We manufacture electrode slurry by the way of ball-milling and mixture, and investigate the effect of solid content and organic vehicle on silk screen printing performance. The results show that solid content affects viscosity of slurry directly. The viscosity between20and50Pa·S is suitable for screen printing. The optimal proportion between solvent and thickener is16:1(wt%). When the content of surfactant and plasticizer is separately2-8%, the leveling property and dispersity of slurry shows well. When the film thickness is about13μm, the performance of electrode is best.The microstructure of surface of these electrode systems and its influencing factors are studied by scanning electronic microscopy, the results show that the sintering temperature has remarkable effect on the microstructure. These results are explained by length of tripe phase boundary (TPB) of electrode, and then the appropriate processing parameters of electrode are optimized. The analysis of interface indicates that the active reaction centers (TPB) of porous metal electrode only lie in the connecting interface between metal particles and YSZ particles; While in Pt/YSZ cermet composite electrode, its active reaction centers expand into the whole three-dimensional region. And the YSZ electrolyte phase in the cermet composite electrode improves combination between electrode and electrolyte.The relation between the sintering temperature of the prepared Pt/YSZ cermet electrode and its microstructure is discussed, and the optimal sintering temperature range is found to manufacture the cermet composite electrode with the favorable microstructure. Under this condition, the composite electrode with three intercrossing and interconnecting networks of metal, electrolyte and gas pore can form the long and continuous enough tripe phase boundary, which helps to the circulation and interchange between the electronic current and oxygen ionic current. So this structure has the optimal electrochemical catalysis.The Ag electrode and Pt/YSZ electrode are studied by electrochemical impedance spectroscopy (EIS). The effect of different equivalent circuits is compared, and then a suitable equivalent circuit model is adopted. It can explain the meaning of components. By measuring the EIS of electrode under different sintered temperatures, the apparent activation energies of the resistance of electrode polarization and electrolysis is figured out.The studies in the paper contribute to application of oxygen sensors.