Preparation of Graphite Single-Crystal from an Iron Solution by a Temperature-Gradient Method

Abstract A graphite single-crystal with maximum dimensions of 30 mm in diameter and 0.24 mm thick was prepared from an iron solution by a temperature-gradient method. A flux of 300–500 g of electrolytical iron, 10 g of graphite powder and silicon powder of 0–5 g for the flux weight were charged in a graphite crucible. Large and thickened graphite single-crystal films of good quality were prepared at 2100°C by repeating 4 times the heating and cooling processes. The cell parameters of the graphite single-crystal film were ao=2.463±0.003 and co=6.708±0.001 Å. The optimum amount of silicon additive was 1 wt% for the flux weight. In order to increase the thickness along the c-axis of graphite single-crystal films, the number of heating and cooling processes should be increased.