六方氮化硼的振动光谱与立方氮化硼的合成

VIBRATIONAL SPECTRA STUDIES ON HEXAGONAL BN CRYSTAL AND THE SYNTHESIS OF CUBIC BN

以X射线衍射分析作参比,分析了高度三维有序到近乱层结构的9种六方氮化硼的红外和拉曼光谱、并进行了立方氮化硼的高温高压合成。光谱分析表明,随着晶性的降低,六方氮化硼的低频红外吸收峰的位置及拉曼谱线等基本振动光谱发生明显的特征性的变化,并伴随出现各自不同的次级光谱结构。合成结果表明,在触媒作用下,立方氮化硼的形成需要六方氮化硼原料有一定的结晶度,但立方氮化硼合成效果与六方氮化硼结晶度并非是简单的单调关系。对振动光谱和合成试验的结果进行了讨论。

X-ray diffraction analysis is used as a reference, the infrared absorption and Raman scattering spectra of various hBN, whose real structures vary from high three-dimensional order to turbostratic structure, are measured. The results indicate that with the lowering of the crystallinity, the position of its low frequency absorption band and FWHM of Raman spectrum lines in fundamental vibrational spectra change characteristiclly, and exhabit distinctive minore peaks respective. cBN synthesis tests are carried out with these hBN as starting materials. The results show that a certain crystallinity of hBN is necessary to the formation of cBN at high pressure and temperature in the presence of metal catalyst. The dependence of cBN synthesis results upon the hBN crystallinity, which is not a simple monotonic relation. The experimental results mentioned above are analysed and discussed.