Abstract
This UCF invention introduces a method and apparatus for measuring the electrical conductivity of metal oxides across extremely high temperatures. The system positions metal oxide pellets inside a high temperature furnace while an external measurement circuit records resistivity under controlled thermal cycling. The method captures the transition of metal oxides from semiconducting to metallic behavior as temperatures rise, enabling reliable characterization over full operational ranges. Analytical correlations derived from the data accurately describe temperature dependent conductivity and can support material evaluation for thermal energy storage, Joule heating, fuel cells, and other high temperature application.
Technical Details: The method uses a custom two probe resistivity apparatus in which platinum wired pellets are heated inside a high temperature furnace while voltage and current are captured through a DAQ system. A “correction run” removes the platinum wire contribution, ensuring that the final measured resistance reflects only the pellet’s intrinsic behavior. Multiple heating and cooling cycles at different ramp rates enable precise analysis of conductivity sensitivity to temperature and thermal equilibrium.
Five representative metal oxides are synthesized via solid state reaction, pressed into pellets, sintered at material specific temperatures, and then tested up to 1200 or 1500?°C depending on the sample. Resistance decreases by 5–6 orders of magnitude with increasing temperature, and Arrhenius based conductivity correlations show clear semiconductor-to-metal transitions. The apparatus and analytical workflow can be generalized to any metal oxide system where high temperature electrical properties are essential.
Benefit
Enables accurate, wide range conductivity measurement far beyond the limits of existing low temperature commercial tools.Novel correction run calibration significantly improves accuracy by removing parasitic wire resistance.Universally applicable to low conductivity and high conductivity oxides without redesigning the apparatus.Provides analytical correlations and insights that support material selection, device optimization, and modeling in high temperature systems.Market Application
Thermal Energy Storage (TES/TCES): evaluation of self heating media and Joule heating materials.Solid Oxide Fuel Cells (SOFCs): characterization of electrode and interconnect oxides.High Temperature Devices: resistive heaters, sensors, and oxygen transport membranes.Commercial Sensors: foundation for developing compact, high temperature electrical conductivity instruments.
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