Method for Resistivity Measurement of Grainy Carbon and Graphite Materials

The article presents the issue of electrical resistivity measurement of carbon materials. The device that was developed by the authors is described and is the subject of a Polish patent. The innovative approach of the setup is based on the possibility of measuring the resistivity of grainy (powdered, dusty) materials without having to conduct their preliminary pressing. The material that is to be analyzed is placed inside the chamber made of electrically non-conducting material. The sample is then compacted with pneumatically driven pistons and the compaction force can be controlled by the air pressure. The device as proposed by the authors works at a pressure of 900 kPa, which is equal to the compaction force of 1.2 kN. Resistivity is calculated on the basis of the voltage drop recorded on the sample length. The research covers the analysis of the influence of carbon material grade and compaction force on the resistivity value. It was stated that the resistivity of the graphite materials that were analyzed here changed within the range of 43⁻172 µm: petroleum coke-360⁻780 µm; the anthracite-1900⁻3900 µm. The experimental method presented here can be used whenever carbon materials are present in the form of grains.