韩国首尔基础科学研究院Ruoff, Rodney S.研究团队报道了金刚石在1atm压力下在液态金属中的生长。相关研究成果发表在2024年4月24日出版的《自然》。

数千万年前（现在），天然钻石在900–1400°C的温度和5–6GPa的压力下，在地球上地幔的金属熔体中形成。根据碳的相图，金刚石在高压和高温条件下热力学稳定。1955年，通用电气公司的科学家发明并使用了一种高压高温设备，利用约7GPa和1600°C的熔融硫化铁合成金刚石。现有的模型认为，只有在高压和高温下才能使用液态金属生长金刚石。

该文中，研究人员使用液态金属，在1atm压力和1025°C下没有籽晶颗粒的金刚石晶体和多晶金刚石膜的生长，打破了这种模式。通过甲烷的催化活化和碳原子向地下区域的扩散，金刚石在由镓、铁、镍和硅组成的液态金属的下面生长。

研究发现，液态金属表面下碳的过饱和导致金刚石的成核和生长，硅在稳定参与成核的四价键合碳团簇方面发挥着重要作用。在中等温度和1atm压力下在液态金属中生长（亚稳）金刚石，为进一步的基础科学研究和这种生长的规模化开辟了许多可能性。

附：英文原文

Title: Growth of diamond in liquid metal at 1 atm pressure

Author: Gong, Yan, Luo, Da, Choe, Myeonggi, Kim, Yongchul, Ram, Babu, Zafari, Mohammad, Seong, Won Kyung, Bakharev, Pavel, Wang, Meihui, Park, In Kee, Lee, Seulyi, Shin, Tae Joo, Lee, Zonghoon, Lee, Geunsik, Ruoff, Rodney S.

Issue&Volume: 2024-04-24

Abstract: Natural diamonds were (and are) formed (thousands of million years ago) in the upper mantle of Earth in metallic melts at temperatures of 900–1,400°C and at pressures of 5–6GPa (refs.1,2). Diamond is thermodynamically stable under high-pressure and high-temperature conditions as per the phase diagram of carbon3. Scientists at General Electric invented and used a high-pressure and high-temperature apparatus in 1955 to synthesize diamonds by using molten iron sulfide at about 7GPa and 1,600°C (refs.4,5,6). There is an existing model that diamond can be grown using liquid metals only at both high pressure and high temperature7. Here we describe the growth of diamond crystals and polycrystalline diamond films with no seed particles using liquid metal but at 1atm pressure and at 1,025°C, breaking this pattern. Diamond grew in the subsurface of liquid metal composed of gallium, iron, nickel and silicon, by catalytic activation of methane and diffusion of carbon atoms into and within the subsurface regions. We found that the supersaturation of carbon in the liquid metal subsurface leads to the nucleation and growth of diamonds, with Si playing an important part in stabilizing tetravalently bonded carbon clusters that play a part in nucleation. Growth of (metastable) diamond in liquid metal at moderate temperature and 1atm pressure opens many possibilities for further basic science studies and for the scaling of this type of growth.

DOI: 10.1038/s41586-024-07339-7

Source: https://www.nature.com/articles/s41586-024-07339-7