During the past years, experts have shown rising interest in developing high-entropy alloys which refer to materials composed of several metallic elements. Because of the new synthesis technique developed by Chinese researchers, it is now possible to develop multi-element nanoparticles using a more diverse range of metals.
Creating the Multi-Element Nanoparticles
Researchers from Wuhan University and the Southern University of Shenzhen discovered a strategy for creating nanoparticles composed of elements that used to be difficult to mix together.
Synthesizing high-entropy alloy nanoparticles (HEA-NPs) usually requires extreme conditions to achieve enough mixing of components. They also need components with similar behavior, such as melting points or atomic radii.
Until now, HEA-NPs are restricted to palettes of the same elements, hindering the design of the material and other features such as mechanical exploration and property optimization. The experimental approach Yang Wang and his team used involved the catalysis of liquid gallium as a matrix to combine many other immiscible metallic elements.
The 17 elements that underwent chemical synthesis include gallium, iron, nickel, copper, zinc, scandium, vanadium, manganese, magnesium, zirconium, platinum, rhodium, ruthenium, iridium, hafnium, molybdenum, and niobium. All of the metals included in nanoparticle formation have melting points ranging from 303 - 3683K.
Catalysis of enthalpy tuning was used to realize the fabricated structures of nanoparticles. Meanwhile, the real-time conversion process of liquid metal to crystalline HEA-NPs confirmed the dynamic fission-fusion property during the alloying process.
A step-alloying strategy was used to synthesize HEA-NPs that contain various strongly repellent elements. This was done by using Rich-Pt cores created during the initial liquid stage reaction as starting point of the second thermal diffusion.
Yang and his team found that liquid metals that mix enthalpy with other elements negatively can offer a stable thermodynamic condition and serve as a good dynamic mixing reservoir. The newly-developed materials can also be used in various industries because of their customizable physical, electronic, and chemical properties.
HEA-NPs are small particles that contain multiple principal metal elements. They demonstrate great potential as functional materials because of their unique complex compositions and customizable properties. The researchers also hope to seek new materials with interesting properties by combining elements with different characteristics.
What are High-Entropy Alloys?
High-entropy allows (HEAs) refers to materials that contain five or more elements in almost equal amounts, forming complex microstructure with high configured entropy. They are created using chemical syntheses like mechanical alloying, casting, and powder metallurgy.
Compared to traditional alloys, high-entropy alloys exhibit several unique properties since the elements that constitute them have different crystal structures. Some of the characteristics possessed by high entropy alloys (HEAs) are thermal stability, hardness, and corrosion resistance. Because HEAs have improved electrical conductivity and magnetic characteristics, they are suitable for various applications, such as biomedical engineering, aerospace, and transportation. It is also possible to tailor the properties of HEAs by modifying their processing conditions, composition, and microstructure.
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