Materials: Ultrahard polycrystalline diamond from graphite

@article{Irifune2003MaterialsUP,
  title={Materials: Ultrahard polycrystalline diamond from graphite},
  author={Tetsuo Irifune and Ayako Kurio and Shizue Sakamoto and Toru Inoue and Hitoshi Sumiya},
  journal={Nature},
  year={2003},
  volume={421},
  pages={599-600}
}
Polycrystalline diamonds are harder and tougher than single-crystal diamonds and are therefore valuable for cutting and polishing other hard materials, but naturally occurring polycrystalline diamond is unusual and its production is slow. Here we describe the rapid synthesis of pure sintered polycrystalline diamond by direct conversion of graphite under static high pressure and temperature. Surprisingly, this synthesized diamond is ultrahard and so could be useful in the manufacture of… 
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