Cracking on the Compaction of a Model Composition Based on Natural Flake Graphite and Binder Pitch

Resumo

The experimental temperature dependence of the electrical resistivity of a model composition based on natural flake graphite was compared with the results of a mathematical simulation performed with the use of a flake graphite polycrystal model. For increasing the section of contacts between flakes, the density of the material was increased as a result of impregnation with pitch and the subsequent calcination. The average values of the sizes of flakes in the composition and the tabular values of the conductivity tensor of a graphite quasi-single crystal served as the parameters of calculations. Based on the results of the mathematical simulation, it was found that temperature cracking due to the shrinkage of flakes on cooling should be taken into account for the correspondence of computed values to the experimental results. This cracking almost ceased at temperatures lower than 200°C regardless of the compaction of the material.