The study of oxidation kinetics of aluminum-based materials is important for understanding their corrosion resistance in various environments. In this paper, a comparative analysis of oxidation of the quasi-crystalline phase i-AlCuFe, the crystalline phase ω-AlCuFe and pure aluminum is carried out.
The oxidation was carried out in a controlled atmosphere at elevated temperatures, using thermogravimetric analysis and differential scanning calorimetry. The results show that the quasi-crystalline phase i-AlCuFe exhibits significantly higher oxidation stability compared to the crystalline phase ω-AlCuFe and pure aluminum.
It is assumed that the increased oxidation resistance of the quasicrystalline phase is due to its complex atomic structure and the formation of a dense protective oxide film on the surface. Further studies, including analysis of the composition and structure of oxide films, are necessary to fully understand the mechanisms determining the oxidative behavior of these materials.
The oxidation of the quasicrystalline i-AlCuFe alloy is studied in comparison with tetragonal ω-AlCuFe and aluminum. At 600 °C and low oxygen pressure (up to 5000 L), significantly smaller oxide thicknesses are detected on i-AlCuFe using AES. After oxidation at 105 L, oxide crystallites are visible on the surface of ω-AlCuFe and aluminum, especially in the center of the grains, which is not the case on i-AlCuFe. Ion etching forms cone-shaped structures on ω-AlCuFe and aluminum, but i-AlCuFe remains smooth. At 700 °C, crystallites appear on icosahedral grains as well. The results indicate different oxide growth kinetics due to the delay in nucleation and growth rate on the quasicrystalline phase. It is assumed that this is due to the impossibility of epitaxial growth of γ-Al2O3 on the aperiodic lattice of i-AlCuFe.
The quasi-crystalline structure of metal alloys has unique properties. The pseudogap in the density of electron states affects the physical properties, making them poor conductors. AlCuFe alloys are popular due to their low cost and non-toxicity. The quasi-crystalline phase i-AlCuFe has high hardness, low friction, and resistance to corrosion and oxidation. The first stages of oxidation of aluminum-based quasicrystals have been studied. For i-AlCuFe, two temperature oxidation regimes preceded by chemisorption have been identified. At low temperatures, a thin amorphous oxide layer is formed, which becomes thicker at temperatures above 400 °C.
The aim of the study is to clarify the mechanisms of nucleation and growth of crystallized oxide on the i-AlCuFe phase compared to crystalline phases. The oxidation of the quasi-crystalline i-AlCuFe phase, the crystalline tetragonal ω-AlCuFe phase and pure aluminum was studied.
Author: D. Rouxel, M. Gil-Gavatz, P. Pigeat, B. Weber
Institute: Laboratory of Physics of Ionized Media and their Applications, UMR CNRS 7040, Faculty of Science, UHP Nancy I, BP 239, Vandoeuvre-lès-Nancy, 54046, France, Laboratory of Surface Science and Engineering, UMR CNRS 7570, School of Mines, Parc de Sorupt, Nancy, 54042, France