A new class of ceramic can be thermoformed into sheet metal
In what they call a “new frontier in materials,” engineers at Northeastern University have developed a new type of ceramic that can be shaped into fine and complex shapes, opening up new and extensive applications in electronics. Described as thermoformable ceramics, the new materials were born out of a lab accident, but could serve as more efficient and durable heat sinks, among other possibilities.
The study authors were toying with experimental boron-based ceramic compounds for potential industrial applications last year and had apparently pushed the material to the breaking point.
“We blew it with a blowtorch, and while we were loading it, it unexpectedly deformed and fell off the fixture,” Randall Erb, professor of mechanical and industrial engineering at Northeastern. “We looked at the sample on the floor thinking it was a failure. We realized it was perfectly intact. It just had a different shape. We tried it a few times and realized we could control deformation.And then we started compression molding the material and found that it was a very fast process.
The behavior of the material ran counter to conventional wisdom about how ceramics are formed and what they are able to withstand. When subjected to extreme temperature changes, these materials are at risk of cracking or shattering, but the team was literally able to apply a blowtorch and keep them in one piece.
“It’s unique: Thermoformable ceramic, from what we’ve seen and read, doesn’t really exist,” said study author Jason Bice. “So it’s a new frontier in materials.”
Closer examination of the materials revealed an underlying microstructure that allows them to transmit heat quickly. During molding and thermoforming, a process typically applied to thermoplastic polymers and sheet metal, the team discovered that ceramics could be shaped into complex geometries, while maintaining good mechanical strength and thermal conductivity.
The fact that the material does not transport electrons and does not interfere with radio frequencies (RF) also works in its favor, when it comes to applications in electronics. In smartphones and other devices, a thick layer of aluminum is used to dissipate heat. But with its set of properties and ability to be less than a millimeter thick and conform to different surfaces, the team sees the ceramic material serving as a more efficient heat sink.
“If you put an aluminum heatsink in an RF component, you’ve basically introduced a series of antennas to interact with the RF signal,” Erb explains. “Instead, we can put our boron nitride material in and around an RF component and it’s essentially invisible to the RF signal.”
The scientists received a grant to further develop the technology and are currently pursuing commercialization through a spin-off company called Fourier.
The research was published in the journal Advanced materials.
Source: Northeastern University