Surface properties of materials play a key role in many technological processes, from soldering and welding to coating and composites. In this regard, the wetting and adhesion characteristics of quasicrystals (QC) and complex metal alloys (CMA) are of considerable interest, since these materials exhibit a unique combination of mechanical, thermal and chemical properties.
CCs, having an aperiodic structure with a long-range order, are characterized by high hardness, low friction coefficient and good corrosion resistance. These properties, in turn, affect their wettability and adhesion. Studies show that the wettability of CCs can vary widely depending on the composition, crystal structure and surface treatment. For example, some CCs exhibit hydrophobic properties, which makes them promising for the creation of self-cleaning coatings.
This paper examines the wettability of aluminum quasicrystals and complex metal alloys (CMA), which are a large group of crystalline compounds whose structural complexity varies depending on their composition. These compounds are characterized by thermodynamic stability and the possibility of producing samples of various shapes, which facilitates the measurement of the physical properties of their surface under atmospheric conditions. Surface energy (γS) is one of the key fundamental properties of condensed media, determining the equilibrium shape of a crystal, the interaction of phases between any liquid and solid bodies, and other phenomena.
The article presents the results of studies on determining the surface energy of a number of quasicrystals, including stable icosahedral quasicrystals AlCuFe and AlPdMn, coated with a natural oxide layer under normal conditions. The relationship between the surface energy and the electron density of states under the oxide layer is experimentally demonstrated, provided that its thickness does not exceed 10 nm. Given the diversity of the studied CMS compounds, special attention is paid to the relationship between the oxide thickness and the characteristics of the electron density of states. The potential application of these materials in non-stick coatings as an alternative to fluorinated surfaces is considered.
Under conditions of thermodynamic equilibrium, the contact angle θ of a drop of liquid located on the (ideally smooth and horizontal) surface of a solid body reflects the balance of the surface tension arising at the liquid-vapor interface, the surface tension of the solid (in the presence of liquid vapor) and the interfacial tension between the solid and the liquid.
Understanding the relationship between the composition, structure and surface properties of CC and SMS is necessary for the development of new materials with improved characteristics for various applications. Further research in this area, aimed at studying the influence of surface treatment, temperature and atmosphere on wettability and adhesion, will help to expand the scope of application of these promising materials.
Author: Jean-Marie Dubois, Esther Belin-Ferret
Institute: Jean Lamoure (CNRS-University of Lorraine UMR 7198), Parc Sorupt, CS54840, 54011, Nancy, France