Synthesis of Diamond in Liquid Metal at 1 Atmosphere Pressure
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-07-11 |
| Journal | ECS Meeting Abstracts |
| Authors | Da Luo |
Abstract
Section titled āAbstractāThere are two conventional methods for growing synthetic diamonds on a scale of one centimeter or larger. One is the chemical vapor deposition (CVD) method, which includes plasma-assisted and hot-filament CVD and is used to create diamond films. The other method is high-pressure high-temperature (HPHT) growth, which accounts for approximately 99% of the synthetic diamonds produced annually [1] . In the HPHT method, carbon dissolved in liquid metals forms diamonds under pressures of 5-10 GPa and at temperatures ranging from 1300-1600 Ā°C. There is a prevailing paradigm that diamond can be formed in liquid metals only under HPHT conditions because diamond is thermodynamically stable in this regime. Itās worth noting that the diamonds produced using HPHT are usually limited to sizes of about one cubic centimeter due to the components involved. Discovering alternative methods to make diamonds in liquid metals under lower pressures is an intriguing basic science challenge that, if achieved, could revolutionize diamond manufacturing. In this talk, I would like to present our recent results on growing diamonds using liquid metals. We developed a liquid metal alloy composed of 77.75/11.00/11.00/0.25 atomic percentages of Ga/Ni/Fe/Si, which facilitates the growth of diamond crystals (hundreds of nanometers in size) and polycrystalline diamond films (a few millimeters in lateral size) using methane at 1 atm pressure and 1025 Ā°C. This challenges the traditional growth model of diamonds [2] . The diamonds were observed growing within the subsurface regions of the liquid metal. We found that carbon becomes āsupersaturatedā in the subsurface, leading to the nucleation and growth of diamonds, and that Si atoms play a critical role in stabilizing sp 3 -bonded carbon clusters, which triggers nucleation. Our growth method offers significant flexibility in the composition of liquid metals; for example, diamonds can also be grown using Ga/Co/Fe/Si and Ga/In/Ni/Fe/Si liquid alloys. It is likely that liquid metal alloys of other compositions would also work for growing diamonds. References [1] Olya Linde, Oleg Geyler, Ari Epstein. The Global Diamond Industry 2018, Bain & Company. [2] Yan Gong, Da Luo, Myeonggi Choe, Yongchul Kim, Babu Ram, Mohammad Zafari, Won Kyung Seong, Pavel Bakharev, Meihui Wang, In Kee Park, Seulyi Lee, Tae Joo Shin, Zonghoon Lee, Geunsik Lee, Rodney S. Ruoff. Nature 2024 , 629 , 348-354.