Analysis of the nanodiamond particle fabricated by detonation

In order to comprehensively analyse the structures and the surface states of the nanodiamond particles fabricated by detonation, various apparatus were used to investigate the nanodiamond powder including a high-resolution transmission electron microscope, an energy diffraction spectrometer, an X-ray diffractometer, a Raman spectrometer, a Fourier transform infrared spectrometer and differential scanning calorimeter. The grain size of the nanodiamond particles was in the range of 2–12 nm. However, the average grain size of the nanodiamond was approximately 5 nm. Moreover, the shapes of the nanodiamond particles were spherical or elliptical. The nanodiamond as fabricated was very pure, containing almost only the element of carbon. The contents of the impure element including O, Al and S were very small, which came from the synthesis and purification processes when fabricating the nanodiamond. The surfaces of the nanodiamond particles absorbed many functional groups, such as hydroxy, carbonyl, carboxyl and ether-based resin. The initial oxidation temperature of the nanodiamond powder in the air was about 520°C, which was lower than that of the bulk diamond. However, the oxidation temperature of the nanographite existing in the nanodiamond powder was about 228°C. The graphitisation temperature of the nanodiamond powder in the Ar gas was approximately 1305°C.