New High-Entropy Oxides Created with Low-Oxygen Synthesis
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Sometimes, having less oxygen truly makes a difference. By lowering oxygen levels during synthesis, a group of materials scientists at Penn State succeeded in creating seven previously unknown high-entropy oxides, or HEOs. These ceramics contain five or more metals and are being explored for uses in energy storage, electronic devices and protective coatings.
During the advancement of these materials, the team also outlined a broader framework for designing future materials. Thier findings were published in Nature Communications.
“By carefully removing oxygen from the atmosphere of the tube furnace during synthesis, we stabilized two metals, iron and manganese, into the ceramics that would not otherwise stabilize in the ambient atmosphere,” saeid corresponding and first author Saeed Almishal, a research professor at Penn State working with Jon-Paul maria, the Dorothy Pate Enright professor of Materials Science.
Early Breakthroughs and Machine Learning Finding
Almishal first achieved stability in a material containing manganese and iron by adjusting oxygen levels in a composition he designated as J52. That sample included magnesium,cobalt,nickel,manganese and iron. After that initial success, he used newly developed machine learning capabilities that can rapidly evaluate thousands of possible formulations.With those tools, he identified six additional metal combinations capable of forming HEOs.
Working alongside undergraduate researchers who helped process,fabricate and characterize samples,Almishal and Maria are continuing to explore the potential of these new materials.
What are High-Entropy Oxides (HEOs)?
High-entropy oxides are a relatively new class of ceramic materials. Unlike traditional ceramics which are typically composed of one or two elements, HEOs contain five or more metallic elements in their structure. This high compositional complexity leads to unique properties, making them promising candidates for various advanced applications.
Why is Oxygen Control Vital?
Oxygen plays a crucial role in the formation and stability of oxides. By carefully controlling the oxygen levels during synthesis, scientists can influence the arrangement of atoms within the material. In this case, reducing oxygen levels allowed the researchers to stabilize metal combinations that wouldn’t normally form stable oxides under normal atmospheric conditions. This opens up new possibilities for creating materials with tailored properties.
Potential Applications of HEOs
- Energy storage: HEOs can potentially improve the performance of batteries and supercapacitors.
- Electronic Devices: Their unique electronic properties make them suitable for use in transistors and other electronic components.
- Protective Coatings: HEOs can provide excellent resistance to wear, corrosion, and high temperatures, making them ideal for protective coatings.
Looking Ahead
This research demonstrates the power of combining controlled synthesis techniques with machine learning to accelerate materials discovery. The framework developed by the Penn State team provides a roadmap for creating a wider range of HEOs with customized properties, paving the way for advancements in various technological fields.