A research team at Southern Methodist University (SMU) has developed a new class of materials that can be processed using additive manufacturing and is characterized by its particular resistance to thermal and chemical stress. The so-called high-entropy oxides (HEO) nanoribbons consist of five or more elements in almost equal proportions and are characterized by a highly disordered atomic structure. This structural entropy significantly improves mechanical stability, corrosion resistance and temperature resistance compared to conventional alloys.
Until now, highly entropic materials were considered cost-intensive and energy-intensive due to their production at high temperatures and as massive bulk structures. The method now presented, on the other hand, enables the production of HEO nanoribbons at room temperature, including by 3D printing or spray coating.
“Most materials are made primarily from one or two elements, but high-entropy materials combine five or more elements in roughly equal proportions,” explains Amin Salehi-Khojin, lead author of the study and professor of mechanical engineering at SMU. “This even distribution leads to a highly disordered atomic structure — what scientists call ‘high entropy’ — which can enhance the material’s strength, resistance to heat, and ability to withstand stress or corrosion.”
The underlying process is based on a two-step synthesis: first, a sulphur element is used to create two-dimensional structures, which are then converted into one-dimensional nanoribbons through targeted oxidation.
“First, a sulfur element was used to etch the samples into two-dimensional (2D) structures, followed by an oxidation process to convert the 2D structures to one-dimensional (1D),” said Ilias Papailias, co-author of the study. “This technique provides over two orders of magnitude control on the width and size of the nanoribbons produced by this approach. It has been discovered that during the oxidation process, the nucleation of 1D ribbons occurs, eventually converting them to full 1D systems upon extended oxidation, as confirmed by a wide range of in-situ experiments.”
“This new method can revolutionize the material science field by introducing new entropy structures,” said Salehi-Khojin, who began research on these nanoribbons at the UIC.
The results published in the journal Science show that the 1D-HEO structures remain stable even at temperatures of up to 1,000 °C, pressures of up to 12 GPa and chemically aggressive environments. Long-term tests in acidic and alkaline solutions showed no structural changes. The researchers see potential applications particularly in aerospace, energy technology and electronics, where there are high demands on material resistance. Further tests are necessary to prepare for integration into industrial applications.
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