Nitrogen Trapping Ability of Hydrogen-Induced Vacancy and the Effect on the Formation of AlN in Aluminum

Abstract

This paper presents the ternary interaction of N, H, and vacancy point defects and the nitrogen trapping ability of aluminum vacancies induced by hydrogen by means of DFT methods employed in VASP (Vienna Ab initio Simulation Package) and Abinit packages. The obtained vacancy formation energy of 0.65 eV is close to experimental values. Although the N-vacancy complex is unstable with the negative binding energy of −0.51 eV, the stability of H-vacancy-N is proved by the positive binding energy of 0.59 eV and the appearance of the orbital hybridization in the density of state (DOS) of atoms connecting to this complex. Moreover, Al vacancies can trap more than 4 N atoms, which prevents the formation of aluminum nitride and subsequently affects not only the hardness of the Al surface but also many practical applications of AlN coating.

Hydrogen delaying the formation of Guinier-Preston zones in aluminium alloys

“…with H sp Vac , S sp Vac , H sp Bulk and S sp Bulk the enthalpy and entropy of the supercell of a perfect crystal with and without a vacancy, respectively. The obtained formation enthalpy H f Vac is equal to 0.64 eV, in agreement with the literature [38,63,64]. In previous work, Naghavi et al have shown how the self diffusion coefficient of Cobalt is impacted by modifying S f Vac [60].…”

A DFT-Based Model on the Adsorption Behavior of H2O, H+, Cl−, and OH− on Clean and Cr-Doped Fe(110) Planes

“…The interaction between small molecules and metal surface is crucial in applied researches such as interfacial catalysis, anisotropic synthesis, anti-corrosion, and so forth [1]. For example, the interfacial reactions involving H 2 O is significantly affected by the adsorption of H 2 O molecules on the metal surface [2,3].…”