Sometimes, less really is more. By removing oxygen during synthesis, a team led by materials scientists at Penn State created seven new high-entropy oxides, or HEOs: a class of ceramics composed of five or more metals with potential for applications in energy storage, electronics and protective coatings.
In the process of synthesizing the new materials, the researchers created a framework using principles of future materials. The team, published their work 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," said corresponding and first author Saeed Almishal, research professor at Penn State working under Jon-Paul Maria, Dorothy Pate Enright Professor of Materials Science.
Almishal first had success stabilizing a manganese- and iron-containing material by controlling oxygen in one composition that he named J52, which consisted of magnesium, cobalt, nickel, manganese and iron. Then, using newly developed machine learning - a subtype of artificial intelligence - capabilities that screen thousands of material compositions in seconds, Almishal identified six additional combinations of metals forming HEOs.
With the help of a team of undergraduate students who processed, fabricated and characterized the samples in the lab, Almishal synthesized bulk ceramic pellets of the seven novel, stable and potentially functional metal HEO compositions. The undergraduate researchers are supported by the Department of Materials Science and Engineering and Penn State's Center for Nanoscale Science, a U.S. National Science Foundation-funded Materials Research Science and Engineering Center.
