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The influence of pressure on high-pressure, high-temperature annealing of type Ia diamond

Research output: Contribution to journalConference paper

F De Weerdt, A T Collins

Original languageEnglish
Pages (from-to)507 - 510
Number of pages4
Issue number3-7
Publication statusPublished - Mar 2003
Event13th European Conference on Diamond, Diamond-Like Materials, Carbon Nanotubes, Nitrides and Sililcon Carbide (Diamond 2002) - GRANADA, Spain
Duration: 1 Jan 2003 → …

King's Authors

Research Groups

  • Physics


The influence of temperature and pressure conditions during high-pressure, high-temperature (HPHT) annealing on the dissociation of nitrogen aggregates is investigated, and special attention is paid to the influence of pressure. When PT conditions are above the diamond-graphite equilibrium line, an activation energy of 5.6 +/- 1.4 eV is calculated from the Arrhenius plot of the dissociation rate of A centres by assuming that the dissociation reaction of A centres follows first order kinetics. A second estimate for the binding energy of the A centres, derived from the equilibrium concentrations of A centres and C centres at three different temperatures, gives a value of 7.66 +/- 0.6 eV. The dissociation rate of A centres is enhanced by a factor of similar to10 when the PT point during the HPHT annealing is located in the graphite stable region of the carbon phase diagram. (C) 2002 Elsevier Science B.V. All rights reserved.

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