P2.6.1 Measurement and Control of Oxygen Partial Pressure at Elevated Temperatures
- 14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
- P2.6 Electrochemical-based Sensors
- M. Schulz, H. Fritze - Institute of Energy Research and Physical Technologies (Germany), C. Stenzel - ASTRIUM - Space Transportation, Department TO5 (Germany)
- 1587 - 1590
A standalone system for measurement and control of the oxygen partial pressure at elevated temperatures in the range from 10^-20 bar to 10^-3 bar is presented. The first part of the system is a potentiometric sensor which exhibits a measurement uncertainty of ?log(pO2/bar) < 0.02. The adjustment of the oxygen partial pressure is realized with an oxygen ion pump. Here, an electric current between -10 and +10 mA is applied to an oxygen ion conductor resulting in oxygen transport into or out of the system. The pump yields an accuracy in oxygen flow of 10^-9 l/min and enables, therefore, the adjustment of pO2 with an uncertainty of ?log(pO2/bar) < 0.02 even in buffers like CO/CO2 o r H 2/H2O close to the stoichiometric composition. Finally, the application of the system in an electromagnetic levitator is discussed. Here, the Ni sample is heated to 1720 °C and the surface tension of the melt as a function of oxygen partial pressure is determined.