Inch-scale ultrahard diamond wafer with 200 GPa hardness via high-frequency pulsed local non-equilibrium growth.

ABSTRACT: Producing inch-scale, binder-free ultrahard diamond presents a formidable challenge due to the limitations of the conventional high-pressure and high-temperature method. Here, we report a customized microwave plasma chemical vapor deposition technique with high-frequency gas-switching control. By periodically introducing nitrogen, a transient local non-equilibrium growth mode is established, enabling the synthesis of free-standing ultrahard diamond wafers up to 3 mm thick and 5 inches in diameter. The wafers exhibit a Vickers hardness of ~208.3 GPa, comparable to the hardest nano-twinned diamonds, and show exceptional wear resistance-abrasive ratio ~7 times higher than polycrystalline diamond substrate. High-resolution transmission electron microscopy reveals an ultra-dense three-dimension

SUBMITTER: Tu J 

PROVIDER: S-EPMC12722708 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature