Author: E. J. Widjaja, L. D. Marks

Institute: Department of Materials Science and Engineering, Northwestern University, Cook Hall, 2225 North Campus Drive, 2036, Evanston, IL 60208-3108, USA

This study presents the results of the analysis of quasicrystalline thin films of the Al–Cu–Fe–Cr system obtained by magnetron sputtering. Quasicrystals, characterized by an unusual fourth symmetry of the structure, have unique physical properties, which makes them extremely interesting for application in various fields, including coating materials and electronic components.

X-ray and electron microscopic studies were conducted, which confirmed the formation of stable quasi-crystalline phases in the obtained films. It was revealed that changing the ratio of components in the initial target structure significantly affects the morphology and mechanical characteristics of the materials. In addition, the thermodynamic properties of the films were studied, including their electrical conductivity and thermal stability.

It is important to note that magnetron sputtering allows control over the deposition parameters, which opens up new possibilities for creating quasi-crystalline structures with specified properties. The prospects for further research include the possibility of optimizing the technological process to achieve an ideal combination of strength, conductivity and corrosion resistance.

Quasicrystals are ordered structures with special rotational symmetries that are not normally allowed by classical crystallography (such as rotation axes of five or ten). These materials, including both quasicrystals themselves and their approximations, exhibit properties that differ significantly from traditional metallic alloys. Quasicrystals typically have high strength and stiffness, but their electrical and thermal conductivities are low. They also have low friction and surface energy, which is well documented in the literature. Pure quasicrystalline materials can be challenging to work with due to their low viscosity, which limits their applicability in most cases. However, their potential as coatings is very high. Plasma spraying is a common method for creating quasicrystalline films, although it has drawbacks such as porosity and cracks. Physical vapor deposition methods are more preferred. The key to successful film production is understanding the initial stages of their growth, which requires a high vacuum environment. In this work, we share initial results of transmission electron microscopy and X-ray photoelectron spectroscopy studies of Al–Cu–Fe–Cr quasicrystalline films and confirm the existence of a new hexagonal approximant for decagonal quasicrystals.