Changes in the Fine Structure of Natural Graphite in the Process of Mechanical Dispersion

Abstract

Changes in the fine structure of natural graphite ground in a planetary mill in an atmosphere of air and Ar + 10% CH₄ are studied by X-ray diffraction. The profiles of the experimentally observed asymmetric maxima of 002 graphite are decomposed into the minimum number of symmetric components described by the Pearson VII function using the Origin program (determination coefficient R² is 0.985–0.999). The asymmetric peaks 002 can be represented as a superposition of the minimum number of components of symmetrical expansion. In this case, the calculated values of the interplanar spacings (d₀₀₂) of the decomposition components are quite close to the values of d₀₀₂ of the metastable states (phases) given earlier in publications. It is shown that the process of dispersion and structural transformations develops along the path of the successive formation of components with an increased interplanar spacing d₀₀₂ in the range from ∼3.36 to ∼3.55/3.68 Å. Dispersion is not limited to a reduction in the particle size of graphite. Replacing the air atmosphere with Ar + 10%CH₄ has the most significant effect on graphite dispersion in the first ~40 min.