Research On Process Optimization Of Oxygen Measuring Chip Based On Zirconia Closed-cavity Electrochemical Oxygen Pump

The oxygen sensor plays an important role in the aerospace field,and plays a key role in maintaining the oxygen concentration in the gas phase space of the fuel tank at a safe value.At the same time,with the progress of society and the enhancement of people ’s health awareness,the demand for high-performance and low-cost oxygen sensors is increasing,which has also led to the research,development and production of higher-precision oxygen sensors.Firstly,based on the working principle of an industrial oxygen sensor,the relationship between the characteristic time td and the ambient oxygen partial pressure is analyzed by theoretical formula derivation.The influence of the structural parameters of zirconia electrolyte on the characteristic time td is studied.The influence of electrolyte conductivity on the characteristic time td is discussed.The results show that the characteristic time td is linearly related to the ambient oxygen partial pressure in theory.At the same time,it is found that the structural parameters of the oxygen sensor pump oxygen chip have a great influence on the td value.A pump oxygen chip is developed.The difference between the pump oxygen chip and the product produced by SST company is that it has the advantages of simple process and lower cost.The electrode of the chip was designed into two different shapes.At the same time,four groups of experiments were carried out by using the control variable method to explore the influence of the structural parameters of the pump oxygen chip on the characteristic time td.The experimental results show that when the porous zirconia protective layer is added to the pump oxygen chip,the sealing of the cavity is improved,and td has a good linear relationship with the oxygen concentration.The oxygen pump chip with cross platinum electrode has a larger contact area with oxygen,faster oxygen pump rate and smaller td value.In summary,the preferred chip structure is a pump oxygen chip with a porous zirconia protective layer and a cross electrode.Compared with the control product,the td has a better linear correlation with the oxygen concentration,and the manufacturing cost is low.And it has a similar td value to the control product.The drift problem of oxygen sensor is studied and analyzed,and the drift phenomenon of oxygen sensor in aging process is mainly discussed.The drift curves of four groups of oxygen sensors were tested by aging.The experimental results show that the oxygen sensor has a large drift phenomenon during the aging process,and this drift is not linear,on the whole,it is negative drift.Some samples still have unstable signals after aging.Because the influence of the environment is excluded,it is caused by the damage of the internal structure of the oxygen sensor.Therefore,aging can also be used as a preliminary judgment of the quality of oxygen sensor detection steps.