强冲击压缩条件下g-C_3N_4向β-C_3N_4直接转化

Strong Shock-Compression of g-C_3N_4 Precursor for Direct Synthesis of β-C_3N_4

为了合成出理论预言的具有致密结构的超硬材料C3N4,运用二级轻气炮加载和冲击回收实验技术,以富含N的g-C3N4为前驱物,在40～65GPa压力下完成了冲击合成实验。在低于51GPa压力时,X射线衍射分析表明,在回收样品中未发现有新相生成,说明g-C3N4是稳定的;而在51～65GPa范围内,回收样品中有新相生成,与理论计算结果对照发现,新相为β-C3N4相,且不含其它结晶相。证实利用冲击合成方法将g-C3N4直接转化为单纯β-C3N4是可能的,对纯净的超硬相碳氮化合物的合成研究具有参考意义。

Using a two-stage light gas gun and shock recovery technique, a series of experiments up to 40 65 Gpa were carried out on the nitrogen-rich material of precursor g-C3N4. The powder X-ray diffractions （XRD） of recovered samples showed that the precursor g-C3N4 was stable under 51 Gpa pressure,while only a new crystalline phase β-C3N4 was obtained during 51-65 Gpa pressure. The results confirm that β-C3 N4 can be synthesized directly from precursor g-C3 N4. This paper is significant for the study of synthesizing pure superhard carbon nitrides.