Synthesis of B-doped diamond using graphite intercalation compounds (GICs)

A new method has been developed to synthesize B-doped diamond with B-doped graphite intercalation compounds (GICs). H3BO3-GICs that were prepared by the electrochemical method using a graphite slice as the anode, and saturated H3BO3 solution as the electrolyte. The stage structure was controlled by the electrolysis time. X-ray diffraction results show that 1–5 mixed stages B(OH)4-GICs were obtained after 15 h of anodic oxidation. The covalent B–C bond was detected by infrared absorption spectra. In order to remove impurity, annealing treatment was carried out at a temperature above 486 °C, which latter is the decomposition temperature of GICs. B-doped diamond was obtained by high-pressure synthesis using B-doped GICs as carbon sources. The structure and properties of the synthetic diamond were investigated by infrared absorption spectra, differential thermal analysis and scanning electron microscopy. The results show the oxidation temperature of the diamond synthesized from B-doped GICs was 1045 °C, which is higher than that of undoped diamond. The covalent B–C bond that lies in B-doped graphite is also present in B-doped diamond. The morphology of B-doped diamond particle shows a mosaic structure of sub-grains. The conclusion drawn from this is that the doping of B atoms leads to more nucleation cites.