Development of Experimental setup for Electricalconductivity Measurement as a Function of Temperature and Oxygen Partial Pressure

Abstract

Conductivity measurement as a function of temperature and partial pressure gives carrier concentration, carrier mobility, and the lifetime of excess carriers. In this project design was selected and the three dimensional design of the final design was made using CATIA (version 5) software, after which the equipment was fabricated using brass. This air tight experimental setup is developed to measure conductivity as a function of temperature and partial pressure. With this setup conductivity is measured using four probe method. Four probe arrangement is made using platinum wires passing through the alumina tube. Conductivity measurement as a function of temperature will give electronic conductivity of the sample. Using the same experimental setup, conductivity relaxation measurement is done to study oxygen transport properties of mixed oxides. Conductivity measurement with respect to partial pressure will give ionic conductivity of the sample. A mixed ionic and electronic conducting oxide i.e., La0.5Sr0.5Co0.2Fe0.8O3-δ (LSCF) powder is synthesized by combustion synthesis. Powder samples were calcined at 6500C with a dwell time of 4hrs resulted in phase purity. High dense samples were obtained by sintering at 12500C for 2hrs. Data acquisition of the setup has been done by using the LABVIEW software. Activation energy of charge carrier is calculated by linear fitting the conductivity data. From conductivity relaxation data we are able to calculate chemical diffusion coefficient and surface exchange coefficient. Finally activation energy, bulk oxygen diffusion, surface oxygen reaction rate constant are calculated.