Oxygen self-diffusion in rutile under hydrothermal conditions

✍ Scribed by P. F. Dennis; R. Freer

• Book ID: 104764704
• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 674 KB
• Volume: 28
• Category: Article
• ISSN: 0022-2461
• DOI: 10.1007/bf00414275

✦ Synopsis

Oxygen self-diffusion coefficients have been determined for synthetic and natural rutile single crystals under hydrothermal conditions at 1 00 MPa total pressure and in the temperature range 873-1 373 K. The diffusion coefficients are lower than the results from dry gas exchange studies would predict. Between 973 and 1373 K the results can be characterized by two linear Arrhenius relationships. D=1.14 x 10 -11 exp(-168.8 kJ mol-1/RT) m -2 s -1 for the natural rutile, and D-2.41 x 10 -12 exp(-172.5 kJ mol-1/RT) m2s -1 for the synthetic crystal. The results have been interpreted in terms of a defect model involving the dissolution of water in rutile as substitutional hydroxyl defects on oxygen lattice sites, with a solution enthalpy in the range 81-1 06 kJ mol-1