本项目拟采用不同粒径范围的洋葱碳纳米粉前驱体制备金刚石纳米粉体。我们将研究高温高压条件下洋葱碳纳米粉前驱体相变前后的结构演化规律，阐明相变机制；表征金刚石纳米粉体的显微组织结构特征（颗粒大小、颗粒内孪晶的平均厚度等）、力学性能及热稳定性，阐明结构与性能的内在联系；实现孪晶结构的金刚石纳米粉体粒径、组织结构和性能的高压调控，发展出结晶性好、力学性能优异、热稳定性高、粒径可控的金刚石纳米粉体的高效制备技术。

In this project, diamond nanopowders will be synthesized from onion carbon nanopowder precursors distinguished by particle size. We plan to investigate the structure evolution of onion carbon nanopowders before and after the phase transition under high pressure high temperature, and clarify the mechanism of phase transition. Also, we will characterize the microstructural features (e.g., particle size, average thickness of nanotwins within the particle, etc.), mechanical properties, and thermal stability of diamond nanopowders, and elucidate the relation between structures and properties. Through the implementation of this project, we expect to regulate the particle size, microstructure, and properties of diamond nanopowders with high pressure, and develop an effective method to prepare diamond nanopowders with good crystallinity, excellent mechanical properties, high thermal stability, and controllable particle size.