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ABSTRACT: Nanosized beta carbon nitride (β-C3N4), of grain size several tens of nanometres, has been synthesized by mechanochemical reaction processing. The low-cost synthetic method developed facilitates the novel and effective synthesis of nanosized crystalline β-C3N4 (a = 6.36 Å, c = 4.648 Å) powders. The graphite powders were first milled to a nanoscale state, then the nanosized graphite powders were milled in an atmosphere of NH3 gas. It was found that nanosized β-C3N4 was formed after high-energy ball milling under an NH3 atmosphere. After thermal annealing, the shape of the β-C3N4 changes from flake-like to sphere-like. The nanosized β-C3N4 formed was characterized by x-ray diffraction, Fourier transformation infrared spectroscopy, and transmission electron microscopy. A solid–gas reaction mechanism was proposed for the formation of nanosized β-C3N4 at room temperature induced by mechanochemical activation.
Journal of Physics Condensed Matter 01/2003; 15(2):309. · 2.55 Impact Factor
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Journal of Materials Science Letters 10/2000; 19(22):2001-2002.
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ABSTRACT: Diamond seed crystals were treated with Fe3C powders under high temperature and high pressure (HPHT). AFM images reveal that high quality homo-epitaxial diamond have been successfully grown on the diamond seed. The homo-epitaxial grown diamond film was also confirmed by laser Raman spectra and a net positive weight gain of the diamonds. It was suggested that homo-epitaxial diamond film could be formed through decomposition of iron carbide under HPHT. This study provides direct evidence for diamond formation directly through decomposition of transition metal carbide, and sets up a very effective way to realize diamond growth different from traditional HPHT method using graphite as a carbon source.
Chemical Physics Letters 363:211-218. · 2.34 Impact Factor
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ABSTRACT: Using the stimulated body fluid (SBF) as solvent, nano-sized single-crystalline HAp fibers have been synthesized in SBF solution at 37 °C without adjusting the pH values during the whole reaction time. The synthesized HAp fibers have a length ranging from 60 nm to 100 nm, a uniform diameter of 3–5 nm. Characterization by high-resolution transmission electron microscopy (HRTEM) shows that the synthesized HAp fibers grow along [0 0 1] or [0 1 0], and there exist structural defects in the synthesized HAp nanofibers. the thermal gravity analysis (TG) and corresponding X-ray powder diffraction (XRD) analysis indicate that the heat treatment temperature for HAp fibers should not be above 700 °C. The HAp fibers with length and diameter in the range of nano-size could be an ideal structure as a specific reinforcement in the biomaterials for bone tissue implantation.
Materials Chemistry and Physics 95(1):145-149. · 2.23 Impact Factor
