Researchers at Northeastern University, Boston, discovered an all-ceramic material that can be compression-molded into complex parts\u2014an industry breakthrough\u2014 that could transform the design and construction of heat-emitting electronics, including cellphones and other radio components.<\/p>\n
It was one of those happy accidents of science. Professor Randall Erb and Ph.D. student Jason Bice were working on a product for a university client\u2014and wound up with an entirely new class of material.<\/p>\n
\u201cOur research group’s lives are very much situated at the bleeding edge of technology,\u201d says Erb, an associate professor of mechanical and industrial engineering who heads the DAPS Lab at Northeastern. \u201cThings break a lot, and every once in a while one of those breaks turns out to be good fortune.\u201d<\/p>\n
Last July, Erb was in his Northeastern lab with Bice, who has since earned a mechanical engineering Ph.D. They were testing an experimental ceramic compound as part of a hypersonic project for an industrial partner when something appeared to go wrong.<\/p>\n
\u201cWe blasted it with a blowtorch and, while we were loading it, it unexpectedly deformed and fell out of the fixture,\u201d Erb says. \u201cWe looked at the sample on the floor thinking that it was a failure.\u201d Closer examination gave way to a revelation.<\/p>\n
\u201cWe realized it was perfectly intact,\u201d Erb says. \u201cIt was just shaped differently.\u201d<\/p>\n
Ceramics tend to fracture (or even explode) from thermal shock when subjected to extreme heat changes and mechanical loading. But their sample had deformed gracefully.<\/p>\n
\u201cWe tried it a few more times and realized that we could control the deformation,\u201d Erb says. \u201cAnd then we started compression-molding the material and found that it was a very fast process.\u201d<\/p>\n
Its underlying microstructure uniquely allows the all-ceramic to quickly transmit heat and flow effectively during the molding process. The ceramic can be formed into exquisite geometries and exhibits impressive mechanical strength and thermal conductivity at room temperature, says Erb, whose findings were recently published in Advanced Materials.
\nErb and Bice are developing the product via their startup, Fourier LLC\u2014named after the French mathematician Joseph Fourier, who studied heat flow in ceramics two centuries ago. Fourier has received a $50,000 Spark Fund award from Northeastern’s Center for Research Innovation.<\/p>\n
\u201cIt’s unique: Thermoformable ceramics, from what we’ve seen and read, don’t really exist,\u201d Bice says. \u201cSo it’s a new frontier in materials.\u201d<\/p>\n
The new product has the potential to introduce two industry improvements, starting with its efficiency as a heat conductor that can cool high-density electronics.<\/p>\n
In general, cellphones and other electronics are fitted with a bulky layer of aluminum, which is necessary to draw heat away from the unit. This material can be less than a millimeter thick, which presents a low-profile solution. It can be molded to conform to the surface to be cooled.<\/p>\n
The phononic crystal-based ceramic allows heat to flow without electron transport. It doesn’t interfere with radio frequencies (RF) of cellphones and other systems.<\/p>\n
\u201cIf you put an aluminum heatsink into an RF component, you’ve basically introduced a series of antennae to interact with the RF signal,\u201d Erb says. \u201cInstead, we can put our boron nitride-based material in and around an RF component and it is essentially invisible to the RF signal.\u201d<\/p>\n
The other improvement, says Erb, is that it can be form-fit directly to the electrical component. Researchers demonstrated the ceramic’s non-Newtonian behavior by subjecting a clumpy slurry of it to vibration that is normal to the manufacturing process; it instantly liquefied and organized the structure of the material. Such slurries are used to produce the moldable ceramics.<\/p>\n
Erb and Bice believe they’ll be able to form-fit the all-ceramic materials to all kinds of electrical components. The ceramic will be thinner, lighter and more efficient than the metals currently in use.<\/p>\n
<\/p>\n