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<p>The adsorption behavior, surface properties, and thermodynamic properties of oxygen atoms adsorbed on the surfaces of Cr<sub>0.5</sub>Al<sub>0.5</sub>N and Cr<sub>0.15</sub>Al<sub>0.85</sub>N were systematically investigated by using first-principles calculations based on density functional theory (DFT). The results indicated that the optimal adsorption site for oxygen atoms on the Cr<sub>0.5</sub>Al<sub>0.5</sub>N surface is the hollow site, followed by Cr-related adsorption sites, and the O atom preferentially forms bond with Cr atom. The energy difference among adsorption sites on the Cr<sub>0.15</sub>Al<sub>0.85</sub>N surface is small, and the Cr–O and Al–O bonds at Al-related adsorption sites are formed. The electronic partial density of states indicated the presence of Cr-d orbital and O-p orbital hybridization in the both structures. Thermodynamic studies revealed that Cr<sub>0.5</sub>Al<sub>0.5</sub>N has a higher Gibbs free energy (ΔG) than Cr<sub>0.15</sub>Al<sub>0.85</sub>N. The ΔG increased significantly with rising temperature in Cr<sub>0.5</sub>Al<sub>0.5</sub>N, indicating that oxygen adsorption is difficult at high temperatures, while it increases slowly with temperature in Cr<sub>0.15</sub>Al<sub>0.85</sub>N, and ΔG approaches zero at low temperatures, suggesting that oxygen adsorption almost occurs spontaneously. The significant difference in ΔG and the temperature response properties are consistent with the thermodynamic behavior of Cr/Al oxides, which provide a clear theoretical basis for material design.</p>

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Study on surface adsorption and oxidation behavior of CrAlN coatings by first-principles calculation

  • 期刊论文

  • 发表日期：

    2025年7月3日

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  • Ergeng Zhang,
  • Jingjing Xu,
  • Biao Huang,
  • Qiong Zhou,
  • Qiang Chen,
  • Dandan Liang

摘要

The adsorption behavior, surface properties, and thermodynamic properties of oxygen atoms adsorbed on the surfaces of Cr0.5Al0.5N and Cr0.15Al0.85N were systematically investigated by using first-principles calculations based on density functional theory (DFT). The results indicated that the optimal adsorption site for oxygen atoms on the Cr0.5Al0.5N surface is the hollow site, followed by Cr-related adsorption sites, and the O atom preferentially forms bond with Cr atom. The energy difference among adsorption sites on the Cr0.15Al0.85N surface is small, and the Cr–O and Al–O bonds at Al-related adsorption sites are formed. The electronic partial density of states indicated the presence of Cr-d orbital and O-p orbital hybridization in the both structures. Thermodynamic studies revealed that Cr0.5Al0.5N has a higher Gibbs free energy (ΔG) than Cr0.15Al0.85N. The ΔG increased significantly with rising temperature in Cr0.5Al0.5N, indicating that oxygen adsorption is difficult at high temperatures, while it increases slowly with temperature in Cr0.15Al0.85N, and ΔG approaches zero at low temperatures, suggesting that oxygen adsorption almost occurs spontaneously. The significant difference in ΔG and the temperature response properties are consistent with the thermodynamic behavior of Cr/Al oxides, which provide a clear theoretical basis for material design.