Oxygen sensors durability

The electrodes and electrode protective coating of the oxygen sensor play a crucial role in determining the performance characteristics and durability (2). The electrodes used are the inner or air-reference electrode and the outer or exhaust gas electrode. The protective coating goes over the outer or exhaust electrode. While a complete discussion of the requirements and properties of the electrodes and electrode protective coating is beyond the scope of this paper, a brief description will be given. 

As a practical electrolyte, yttria-doped zirconia is used. The yttrium doping contributes considerably to stabilizing high-temperature phases of zirconia with a high ionic conductivity and to obtain an excellent, durable material for surviving thermal shock. In a commercial oxygen sensor, a porous platinum electrode is placed on the zirconia... 

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