Title :

Oxidation and Equilibrium Morphology of Zirconium Carbide Low Index Surfaces Using DFT and Atomistic Thermodynamic Modeling

Author(s) :

Osei-Agyemang, Eric [Auteur]
Paul, Jean-Francois [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Lucas, Romain [Auteur]
Foucaud, Sylvie [Auteur]
Cristol, Sylvain [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181

Journal title :

The Journal of Physical Chemistry C

Volume number :

120

Pages :

8759-8771

Publication date :

2016-04-01

HAL domain(s) :

Chimie/Chimie théorique et/ou physique

English abstract : [en]

ZrC is a nonoxide high-temperature ceramic used for applications in harsh environments with corrosive and oxidizing conditions like nuclear reactor and nozzle flaps of jet propulsion engines. Moreover, easy oxidation of ...
Show more >ZrC is a nonoxide high-temperature ceramic used for applications in harsh environments with corrosive and oxidizing conditions like nuclear reactor and nozzle flaps of jet propulsion engines. Moreover, easy oxidation of the crystal surfaces affects the excellent mechanical and physical properties. It is however imperative to study the oxidation processes on the different low index surfaces. DFT studies in conjunction with atomistic thermodynamic modeling have been used for this purpose. The (100) surface completely dissociates molecular oxygen into atomic species, and the surface is fully covered with oxygen atoms at a wide range of temperatures and pressures, recovering the bare surface at temperatures in excess of 1500 K. The (111) surface interacts strongly with O2 by completely dissociating it into atomic species which adsorb at 3-fold fcc hollow sites. This surface is extremely difficult to clean of oxygen by manipulation of temperature and pressure alone. The bare surface cannot be recovered even at temperatures above 1800 K. The (110) surface on the other hand has a complex oxidation process, accumulating eight O atoms leading to the formation of surface ZrO2 units with the release of CO2. This ZrO2-covered surface is highly stable and cannot be removed at temperatures below 2000 K by manipulating temperature and pressure alone. Wulff construction of the equilibrium morphology of the nanocrystallites upon oxidation reveals only the ZrO2-covered (110) surface.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

ENSCL
CNRS
Centrale Lille
Univ. Artois
Université de Lille

Collections :

• Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181

Research team(s) :

Modélisation et spectroscopies (MODSPEC)

Submission date :

2019-09-25T14:05:08Z