In situ x-ray diffraction of graphite-diamond transformation using various catalysts under high pressures and high temperatures

In situ x-ray diffraction studies of graphite-diamond transitions with various solvent catalysts under high pressures and high temperatures at the Photon Factory and SPring-8 are reviewed. By combining synchrotron radiation and a large-volume multi-anvil high-pressure apparatus, real-time observations have been successful in the diamond formation process with the help of various catalysts, such as transition metals, carbonates and aqueous fluids. The experimental procedures and the technical details are described. The diffraction data with various catalysts are shown and the problems and limitations of this method are discussed.