The crystal texture of thin, single graphite flakes extracted from molten pig iron has been studied by electron diffraction and a reflecting optical microscope. It has been found that each flake consists of two arrangements of single crystals having definite orientations on both sides of the flake surface, and the twinning plane varies for each flake, being (120),(134 ),(156 ),(167 )or a more complicated indexed plane. It was impossible to explain the mechanism of the formation of these twins from the stable graphite structure only. On the other hand, the existence of β-SiO2 crystal as an inclusion in such graphite flakes has been detected by electron diffraction. Further experiments have shown that the β-SiO2 crystal yields a ``parallel growth'' with the graphite crystal and forms a nucleus of growth of the latter.From these data, it is concluded that the nucleation of flake graphite may occur at the vacant sites in the β-SiO2 crystal.
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