The National Science Foundation funded the study.
The objective is to create a useful material with a specific geometry, or microstructure, for various applications. The team has employed a technique called solid-state synthesis, where a chemical reaction between two different phases forms a new third phase with a controlled, predetermined shape.
In this case, the desired product is an entropy-stabilized ceramic, which remains thermodynamically stable at high temperatures. This method allows for the precise creation of materials with new features that were previously unattainable.
Chan likened the process to laying two different types of patio pavers in a garden.
Grass grows at the interface between the different stones, and it is the grass phase that we are interested in. By putting the stones in a certain arrangement, we are controlling where and how much grass there is. We want to control that third phase, the grass, if you will, in the reaction.
Helen M. Chan, Professor, Lehigh University
During the research, the team made an unexpected discovery about the third phase.
Chan said, “That third phase was a single crystal, and it is usually very difficult to get single-crystal growth that you can template. The combination of the single-crystal interface with those other two phases could, in fact, contribute to the functional properties of the system.”
This ability to create single-crystal phases with specific microstructures could lead to technological advancements in electronics, energy conversion, and other fields. For example, the materials might be used in thermoelectric devices that generate power from waste heat.
These thermoelectrics are highly desirable because they can convert heat energy into a voltage, which is a more useful form of electrical energy.
Jeffrey M. Rickman, Professor, Lehigh University
In addition to practical applications, the research aims to explore fundamental questions about the mechanisms driving solid-state synthesis by combining advanced modeling with experimental work.
Rickman said, “We want to understand the physics behind the reaction, and the modeling aspect will allow us to model the formation of this new useful phase. How do the atoms come together? How does the material deform during a reaction? How does this long-range transport of the atoms at the interface occur? It is an interesting project in that we are both producing new and useful products, but we are also contributing to the fundamental science driving these reactions.”