Abstract In this paper, diamond crystals are successfully synthesized by adding magnesium silicate pentahydrate (Mg2Si3O8·5H2O) into the Fe–Ni–C system at 5.8–6.3 GPa pressure and 1300–1420 °C temperature. Our results show that the decomposition products of Mg2Si3O8·5H2O under high temperature and high pressure have significant inhibitory effects on the nucleation and growth of diamond. Moreover, with add the amount, the temperature and pressure of synthetic diamond also gradually increased. The SEM shows that the surface defects of the crystal also increase with the increase of the add amount. The IR spectroscopy results show that the content of nitrogen decreases with the increase of the add amount of Mg2Si3O8·5H2O in the crystals. The Raman spectrum shows that the Raman peak of the crystal shifts to the right as the added amount of Mg2Si3O8·5H2O increases. The PL spectrum results show that the increase in magnesium silicate pentahydrate reduces the intensity of NV− and NV0 centers in the crystal. Therefore, our research results provide important ways for understanding the formation mechanism of natural diamond.

中文翻译：

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Fe-Ni-C体系中加入五水硅酸镁合成金刚石的研究

摘要 本文通过将五水硅酸镁（Mg2Si3O8·5H2O）加入到Fe-Ni-C体系中，在5.8-6.3 GPa压力和1300-1420°C温度下成功合成了金刚石晶体。我们的研究结果表明，Mg2Si3O8·5H2O在高温高压下的分解产物对金刚石的形核和生长具有显着的抑制作用。而且，随着添加量的增加，人造金刚石的温度和压力也逐渐升高。SEM表明，随着添加量的增加，晶体的表面缺陷也增加。红外光谱结果表明，随着晶体中Mg2Si3O8·5H2O添加量的增加，氮含量降低。拉曼光谱表明，随着Mg2Si3O8·5H2O添加量的增加，晶体的拉曼峰向右移动。PL 光谱结果表明，五水硅酸镁的增加降低了晶体中 NV- 和 NV0 中心的强度。因此，我们的研究成果为理解天然金刚石的形成机制提供了重要途径。