爆炸冲击合成多晶C_3N_4的研究

Study on Polycrystalline C_3N_4 Prepared by Blast Shock

研究新合成方法下得到超硬材料C3N4,利用黑索今(RDX)炸药作为高温、高压源,以双氰胺(C2H4N4)为主要前驱体.通过扫描电子显微镜(SEM)、X射线衍射分析仪(XRD)、X射线能谱分析仪(EDS)及红外光谱仪(FTIR)分别对输出压力为16GPa时制得样品的结构、形貌、价键特性和元素组成进行了分析与表征.结果表明,XRD测试数据与理论计算值相符很好,样品中同时含有α、β、石墨相C3N4以及晶间相;样品中C、N元素质量比为1.00∶2.98,两种元素主要以C-N形式成键;利用扫描电子显微镜观测到线度为2μm的六边形β-C3N4晶粒.采用爆炸冲击合成方法合成出多晶C3N4粉末,并对其合成机理进行了讨论.

A new technique was developed to synthesize the superhard material C3 N4 in which high pressure and temperature needed in the reaction were supplied by RDX explosive charge and dicyandiamide （C2H4N4） was used as the primary precursor. The structure, valence-bond character and elemental composition of the sample prepared under 16GPa pressure were characterized by the scanning electron microscope （ SEM）, X-ray diffraction analysis （XRD） , X-ray photoelectron spectroscopy analysis （EDS） and infrared spectrometer （FTIR） respectively. The results show that the XRD pattern is in accordance with the theoretical value, i. e. , α-C3N4, β-C3N4, graphite-C3N4 and intercrystal-C3N4 are recognised in the products. The mass ratio of carbon to nitrogen is about 1.00：2.98 and nitrogen is mostly bonded with carbon by C--N. Some hexagonal β-C3N4partieles with size of 2μm are observed through SEM. Powder of polycrystalline C3 N4 is synthesized successfully and its formation mechanism is discussed.