炸药爆轰法制备纳米石墨粉及其在高压合成金刚石中的应用

Nano-graphite synthesized by explosive detonation and its application in preparing diamond under high-pressure and high-temperature

介绍了一种制备纳米石墨粉的新方法———负氧平衡炸药爆轰法 .对合成的黑粉产物进行x射线衍射分析 ,确认其为石墨结构 ,平均晶粒度为 2 58nm .透射电子显微分析的结果表明 ,炸药爆轰法制备的黑粉为六方结构的纳米石墨粉 ,颗粒呈球形或椭球形 .用小角x射线散射法测定纳米石墨粉的粒度分布在 1— 50nm ,有 92 6wt %的粉末粒度小于 16nm .平均粒径为 8 9nm .纳米石墨粉的比表面积约为 50 0— 650m2 g .在六面顶压机中用纳米石墨粉在Fe粉触媒的作用下进行金刚石的高压合成实验 .实验结果表明 ,约在 12 50— 13 3 0K的范围内 ,有金刚石颗粒生成 ,颗粒尺寸为 5— 15μm ,呈球状或块状 .这一合成温度比用普通石墨合成金刚石的温度低约 3 0

In this article, preparation of nano_graphite powders in a steel chamber by usi ng pure TNT (trinitrotoluene) explosives has been reported. X_ray diffraction results indicated that the black solid powders which were collected from the wall and the bottom of the chamber after detonation have the graphite structur e and the average size of the particles of the graphite is 1 86-2 58 nm. Tran smission electron microscopy confirms that the black powder is hexagonal_graphite structure with ball or ball_like shape. The grain s ize of the nano_graphite measured by small angle x_ray scattering lies in the range of 1-50 nm, 92 6wt% of the powder particles is smaller than 16 nm and the average diameter of the grains is 8 7 nm. Specific surface area of the nano_graphite is about 500-650 m 2 /g. Using nano_gra phite as carbon source and choosing Fe powders as the catalyst, the ball_like an d lumpy diamonds of 5-15 μm have been synthesized under high_temperature and h igh_pressure conditions of 1250-1330 K and 5 1 GPa. The synthesized temperatur e is about 300 K lower than that of bulk graphite synthetic diamond.