Annealing studies of boron-doped graphite by Electron Microscopy and X-ray Diffraction

摘要: By heating amorphous boron near its melting point in a reactor grade graphite crucible it has been possible to produce single crystals of containing up 4% boron. These have studied before and after heat treatments by Electron Microscopy, X-ray Diffraction Mass Spectrometer analysis. A model is proposed explain the results which necessitates occupying both interstitial substitutional sites. The former causes c-axis lattice parameter expansion, latter caising contraction a-axis expansion. population diffuses away low temperature anneals 1200°–1400°C whilst 2% remains stable until 2000°C, when leaving behind supersaturation vacancies precipitate as loops. Differences between vacancy loop distributions specimens annealed cleavage into thin foils cleaved annealing lead conclusion that can diffuse along graphite.