Next Article in Journal
A Computational Algorithm to Understand the Evolution of Size Distribution with Successive Breakage Events at Grinding
Previous Article in Journal
Feasibility of the Bio-Mobilization of Rare Earth Elements from Bauxite Residual Red Mud
Proceeding Paper

Silicon Self-Diffusion in Stishovite: Calculations of Point Defect Parameters Based on the cBΩ Thermodynamic Model

1
Institute of Physics of Earth’s Interior and Geohazards, and UNESCO Chair in Solid Earth Physics and Geohazards Risk Reduction, Hellenic Mediterranean University Research Center, 73100 Crete, Greece
2
Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 15784 Athens, Greece
*
Author to whom correspondence should be addressed.
Presented at the 2nd International Electronic Conference on Mineral Science, 1–15 March 2021; Available online: https://iecms2021.sciforum.net/.
Academic Editor: Paul Sylvester
Environ. Sci. Proc. 2021, 6(1), 6; https://doi.org/10.3390/iecms2021-09341
Published: 25 February 2021
(This article belongs to the Proceedings of The 2nd International Electronic Conference on Mineral Science)
In the present work we apply the cBΩ thermodynamic model to study the diffusion of Si in stishovite crystal at high pressure and in a wide temperature range. According to this model, the point defect activation Gibbs free energy is expressed as a function of the bulk properties of the material, i.e., gact = cBΩ, where B is the isothermal bulk modulus, Ω is the mean atomic volume, and c is a dimensionless constant. In this way, other important point defect parameters, such as the activation volume vact, the activation entropy sact, and the activation enthalpy hact may be estimated if the thermoelastic properties of the material are known over a wide temperature and pressure range. Our calculations are based on previously reported self-diffusion coefficients in stishovite single crystals measured at 14 GPa and at temperatures from 1400 to 1800 °C, in the [110] and [001] directions, by Shatskiy et al. (Am. Mineral. 2010, 95, 135–43). Furthermore, the EOS of stishovite, proposed by Wang et al. (J. Geophys. Res. 2012, 117, B06209) has been used for the accurate implementation of the cBΩ model. Our results suggest that the aforementioned point defect parameters exhibit considerable temperature dependence over the studied temperature range (1000–2000 °C). The estimated activation volumes (4.4–5.3 cm3/mol, in the range of 1400–1800 °C) are in agreement with reported experimental results. Our study confirms the potential of the cBΩ model for the theoretical investigation of diffusion processes in minerals, in order to overcome the experimental difficulties and the lack of experimental diffusion data in mantle conditions.
Keywords: stishovite; self-diffusion; thermodynamic modeling; activation volume; high temperature; high pressure stishovite; self-diffusion; thermodynamic modeling; activation volume; high temperature; high pressure
MDPI and ACS Style

Saltas, V.; Vallianatos, F. Silicon Self-Diffusion in Stishovite: Calculations of Point Defect Parameters Based on the cBΩ Thermodynamic Model. Environ. Sci. Proc. 2021, 6, 6. https://doi.org/10.3390/iecms2021-09341

AMA Style

Saltas V, Vallianatos F. Silicon Self-Diffusion in Stishovite: Calculations of Point Defect Parameters Based on the cBΩ Thermodynamic Model. Environmental Sciences Proceedings. 2021; 6(1):6. https://doi.org/10.3390/iecms2021-09341

Chicago/Turabian Style

Saltas, Vassilios, and Filippos Vallianatos. 2021. "Silicon Self-Diffusion in Stishovite: Calculations of Point Defect Parameters Based on the cBΩ Thermodynamic Model" Environmental Sciences Proceedings 6, no. 1: 6. https://doi.org/10.3390/iecms2021-09341

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop