Thermodynamics of oxides with substitutional disorder A microscopicmodel and evaluation of important energy contributions

Date

1998-03-01

Author

Ceder, Gerbrand
Kohan, Adrian
Aydınol, Mehmet Kadri
Tepesch, Patrick
Vanderven, Anton

Metadata

Show full item record

Item Usage Stats

124
views

0
downloads

The first‐principles calculation of finite‐temperature phase stability and thermodynamic properties of multicomponent oxides presents a significant challenge. The time scale on which substitutional disorder occurs prevents the use of standard simulation methods, and a correct description of entropic effects requires that excitation energies can be calculated accurately on the scale of kBT. A model is presented in which substitutional disorder is parameterized with a cluster expansion. The thermodynamics of this model can be easily obtained with lattice model statistical mechanics. The only input required to the procedure is a description of bonding in the system, which is used to calculate the energy of ordered ionic configurations. This method is applied to the CaO‐MgO, Gd2O3‐ZrO2, CaO‐ZrO2 systems, and to LixCoO2 (x between 0 and 1) electrodes for rechargeable lithium batteries. In almost all cases, a correct description of the charge state of the ions is essential to obtain the proper mixing behavior. Only for a highly ionic material such as CaO‐MgO does the charge state of the ions remain unvaried upon mixing. We find that approximate energy models that employ fixed charges will tend to overestimate the energy required for mixing, hence the order‐disorder transition temperature.

URI

https://hdl.handle.net/11511/80784
https://www.researchgate.net/publication/229738692_Thermodynamics_of_Oxides_with_Substitutional_Disorder_A_Microscopic_Model_and_Evaluation_of_Important_Energy_Contributions

Journal

Journal Of The American Ceramic Society

Collections

Department of Metallurgical and Materials Engineering, Article

Suggestions

OpenMETU
Core

THERMODYNAMIC QUANTITIES AT HIGH PRESSURES IN THE i AND theta PHASES OF SOLID NITROGEN DEDUCED BY RAMAN FREQUENCY SHIFTS FOR THE INTERNAL MODES IN LITERATURE Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2013-04-10) The pressure dependence of the Raman frequencies of the internal modes is analyzed (T = 300 K) for the phases i and theta of solid nitrogen using the experimental data from the literature. Through the mode Gruneisen parameter, the isothermal compressibility kappa(T), thermal expansion alpha(p) and the specific heat C-p - C-v are calculated as a function of pressure using the Raman data in these phases.
Kinetic analysis of in situ combustion processes with thermogravimetric and differential thermogravimetric analysis and reaction tube experiments Kök, Mustafa Verşan (1995-01-01) This research comprises the determination of kinetic parameters of in situ combustion processes by reaction tube and thermal (thermogravimetric analysis (TGA)/differential thermogravimetric analysis (DTGA)) experiments. A previously developed laboratory model and a Du Pont 9900 thermalanalyzer unit were used to run the experiments. Three reaction regions for combustion of crude oil in porous media were observed in the reaction tube and TGA/DTGA experiments and are defined as low temperature oxidation, fuel ...
Direct Calculation of Entropy Generation by Solving Reynolds-Averaged Entropy Transport Equation in an Air-Cooled Turbine Cascade Orhan, Omer Emre; Uzol, Oğuz (2012-06-15) This paper presents an implementation of directly solving Reynolds-Averaged Entropy Transport equation as a part of the CFD solution to predict entropy generation rates in a two-dimensional turbine blade stator section. The Reynolds Averaged Entropy Transport and the necessary modeling. equations are implemented to a commercial CFD solver as a User Defined Scalar (UDS). The results are compared with those obtained by post-processing the temperature and velocity fields obtained by solving full Navier-Stokes ...
Thermo-Elastic and Lattice Dynamical Properties of Pd3X (X = Ti, Zr, Hf) Alloys: An Ab Initio Study Sürücü, Gökhan; Colakoglu, K.; ÇİFTCİ, YASEMİN; Ozisik, H. B.; Deligoz, E. (2015-12-01) Using the generalized-gradient approximation (GGA) based on density functional theory, we have reported the structural, mechanical, electronic, and lattice dynamical properties of the intermetallic compounds Pd3X (X = Ti, Zr, Hf) with D0(24) and the L1(2) structures. The elastic constants were predicted using the stress-finite strain technique. We performed numerical estimations of the bulk modulus, shear modulus, Young's modulus, Poisson's ratio anisotropy factor, G/B ratio, and hardness. Our studies have ...
Theoretical investigation of quercetin and its radical isomers Erkoc, E; Erkoc, F; Keskin, N (Elsevier BV, 2003-08-01) The structural and electronic properties of quercetin and its five radical isomers have been investigated theoretically by performing semi-empirical molecular orbital theory calculations. The geometry of the systems have been optimized and the electronic properties of the systems considered have been calculated by semi-empirical self-consistend-field molecular orbital theory at the level AM1 within UHF formalism in their ground state. Conclusions have been drawn by comparing with experimental results.

Citation Formats

G. Ceder, A. Kohan, M. K. Aydınol, P. Tepesch, and A. Vanderven, “Thermodynamics of oxides with substitutional disorder A microscopicmodel and evaluation of important energy contributions,” Journal Of The American Ceramic Society, pp. 517–525, 1998, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/80784.