Scientists from the universities of Minnesota (U.S.) and Kiel (Germany) have created shape-memory ceramics, paving the way for a completely new kind of functional material.
Inspired by the solid-to-solid phase transformation exhibited by some shape memory alloys, the scientists have encouraged similar behavior in ceramics by fine tuning the distances between atoms with the help of compositional changes.
According to The Engineer, although some experimental attempts ended in samples exploding or collapsing into powder, the team ultimately achieved a reversible transformation, easily moving back and forth between the phases, much like a shape memory material.
“We were quite amazed by our results. Shape-memory ceramics would be a completely new kind of functional material,” notes Minnesota professor and study co-author Richard James.
“There is a great need for shape memory actuators that can function in high temperature or in corrosive environments. But what excites us most is the prospect of new ferroelectric ceramics. In these materials, the phase transformation can be used to generate electricity from small temperature differences.”
The team at Germany’s Kiel University was responsible for the experimental part of the study as well as the chemical and structural investigation at the nanoscale.
“For the explanation of our experimental discovery that, contrary to expectation, the ceramics are extremely incompatible and explode or decay, the collaboration with Richard James’ group at the University of Minnesota was very valuable,” says Kiel professor and fellow co-author Eckhard Quandt.
“The theory developed on this basis not only describes the behavior, but also shows the way to get to the desired compatible shape memory ceramics.”
According to James, the collaboration between the two institutions has been core to the project’s success, with different ideas and approaches eventually helping the team push the boundaries of what is possible with ceramic materials.
He contends that their study could lead to a new class of shape-shifting ceramics benefiting medical devices, electronics and even energy generation.
Image and content: Jascha Rohmer, Kiel University/The Engineer