利用温度梯度法,在6.5 GPa、1 300~1 350 ℃的高温高压极端物理条件下,通过在FeNiCo-C合成体系中添加硫脲(CH4N2S)成功合成了金刚石,所合成的晶体呈现出黄色且具有六-八面体形貌。利用扫描电镜(SEM)对所合成金刚石的表面形貌进行了表征,测试结果表明,随着合成体系中CH4N2S添加量的逐渐增加,所合成金刚石的表面变得逐渐粗糙。借助傅里叶红外(FT-IR)光谱对金刚石样品内部的氮、氢缺陷以及化学键结构进行了测试分析,结果表明,金刚石中的氢元素以-CH3, -CH2-, C-H形式存在,而其内部的氮杂质以C心、A心形式存在。此外,在3 300~3 600 cm-1观察到NH的吸收带。

Diamond crystals were synthesized in FeNiCo-C system with CH4N2S additive at pressure of 6.5 GPa and temperature ranging from 1 300 ℃ to 1 350 ℃, using temperature gradient (TGM) method. The obtained diamond crystals displays yellow color and exhibits cub-octahedral morphology. The surface morphology was characterized by SEM and the results indicate that the surface of the obtained diamond become rougher and rougher with the increasing of CH4N2S addition content in the synthesis system. Furthermore, the Nitrogen (N) and Hydrogen (H) defects and chemical bond structures were analyzed in detail with the help of FT-IR spectra. FT-IR results display that H element exits in the forms of -CH3, -CH2-, C-H and N defects locate in the forms of C, A centers. Additionally, the band locating at 3 300-3 600 cm-1 was observed, attributing to NH absorption.