A protective layer coating on the electrode of potentiometric oxygen sensor in automobile is commonly used to clean exhaust gas. Influences of the preparation procedure and the material of the protective layer on output voltage,lifetime and response time of the potentiometric oxygen sensor have been thoroughly investigated. The experimental results show that there are huge differences between the measured values and the realistic values for the output voltage of the potentiometric oxygen sensor when the materials of 20% mass fraction silica gel is used to fabricate the protective layer can react with sensor's electrode material or electrolyte material. The lifetime of the protective layer can be enhanced by adding some YSZ powder into the protective layer. Response times of the potentiometric oxygen sensor are closely related to the physical parameters (thickness and pore size) of the protective layer and sensor' s working temperature.%汽车尾气净化用电势型氧传感器的电极表面通常涂覆有一层保护层,以“过滤”废气中的杂质.考察了保护层制作工艺和保护层物理参数对电势型氧传感器稳态输出电压、使用寿命和响应时间的影响,结果表明:1)当制备保护层所使用的材料(主要是高温粘结剂)和传感器电极或电解质发生化学反应时,测量得到的稳态输出电压也会和真实值相差甚远.选定质量分数为20％硅胶作为高温粘结剂可制备得到性能优良的传感器保护层；2)在保护层制备过程中加入适当比例的YSZ粉末材料,可使电极保护层的使用寿命提高；3)传感器的总响应时间与传感器保护层的物理性能(厚度、孔径等)和传感器的工作温度密切相关.
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