Understanding the surface adsorption and oxidation of cubic Cr<sub>0.5</sub>Al<sub>0.5</sub>N by first-principles calculations
Bulk and surface properties of oxygen in cubic c-Cr0.5Al0.5N were investigated through first-principles calculations based on density functional theory (DFT) in the present work. It was observed that the (0 0 1) surface of c-Cr0.5Al0.5N terminated with Cr-Al-N is energetically favorable. Calculations of oxygen adsorbed on the (0 0 1) surface show that O is bonding with Cr preferentially instead of Al due to the stronger Cr-O bond strength in comparison with that of Al-O. The difference charge density and electronic density of states indicate that the electrons shared between O and Cr and hybridization between the O-p and Cr-d orbitals contribute to the formation of strong Cr-O bonding on the surface. An oxidation mechanism is proposed, i.e. the Cr-O bond is first established, resulting in the formation of α-Cr2O3, and subsequent incorporation of α-Al2O3 promotes the formation of a mixed (Cr, Al)2O3 scale.
|Work Title||Understanding the surface adsorption and oxidation of cubic Cr<sub>0.5</sub>Al<sub>0.5</sub>N by first-principles calculations|
|License||In Copyright (Rights Reserved)|
|Publication Date||August 1, 2021|
|Publisher Identifier (DOI)||
|Deposited||November 17, 2021|
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