Resistive zirconia oxygen sensor

In the structure of the zirconia oxygen sensor, the sensor element is stored in the metal shell consisting of a metal with heater resistance. The sensor element is supported by talc in the metal shell by filling press. The gas detection portion which is exposed to the exhaust gas, is covered with a protection tube made... 

During the last 25 years, the plug-type gas sensors have shown a greater mechanical integrity than other types of zirconia-based sensors of similar construction, and thus have lower leak rates and greater resistance to thermal and/or mechanical shock, factors which produce long sensor lifetimes and enable in-situ oxygen probes to be used in applications found to be beyond the capability of the other zirconia-based probes. 

Zirconia (Zr02) stabilized in its high temperature, cubic form by addition of 8 to 12 mol.% yttria or scandia is currently the materials of choice in devices utilizing a solid-state oxide ion conducting electrolyte, eg oxygen sensors, oxygen pumps and solid oxide fuel cells (SOFCs), because of its good oxide ion conductivity and redox resistance [1-4]. Improvements in conductivity, however, are necessary to enhance theirs performance and efficiency. 

Titanium dioxide is an n-type semiconductor that is used in thin-film oxygen and humidity sensors [155, 156]. Doping with other metal oxides (e.g., iron oxides) increases the sensitivity and selectivity of the titania oxygen sensors [157, 158]. In comparison to zirconia, titania sensors have a better resistance against lead poisoning. 

M. (2005) Temperature independent resistive oxygen sensors using solid electrolyte zirconia as a new temperature compensating material. Sens. Actuators B Chem., 108 (12), 216 222. 

Sensors for measurements of oxygen in molten steel are the most important application in liquid metal sensing. As an electrolyte MgO partially stabilized, zirconia is used because of its high thermal shock resistance due to phase transformations. 

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