For the first time, researchers have created a nanocomposite of ceramics and a two-dimensional material, opening the door for new designs of nanocomposites with such applications as solid-state batteries, thermoelectrics, varistors, catalysts, chemical sensors and much more.
Sintering uses high heat to compact powder materials into a solid form. Widely used in industry, ceramic powders are typically compacted at temperatures of 1472 degrees Fahrenheit or higher. Many low-dimensional materials cannot survive at those temperatures.
But a sintering process developed by a team of researchers at Penn State, called the cold sintering process (CSP), can sinter ceramics at much lower temperatures, less than 572 degrees F, saving energy and enabling a new form of material with high commercial potential.
“We have industry people who are already very interested in this work,” said Jing Guo, a post-doctoral scholar working in the group of Clive Randall, professor of materials science and engineering, Penn State. “They are interested in developing some new material applications with this system and, in general, using CSP to sinter nanocomposites.” Guo is first coauthor on the paper appearing online in Advanced Materials.
by Yury Gogotsi, Asia Sarycheva, and Babak Anasori
Spraying an antenna onto a flat surface. Drexel University Nanomaterials Lab, CC BY-ND
Hear the word “antenna” and you might think about rabbit ears on the top of an old TV or the wire that picks up radio signals for a car. But an antenna can be much smaller – even invisible. No matter its shape or size, an antenna is crucial for communication, transmitting and receiving radio signals between devices. As portable electronics become increasingly common, antennas must, too.
Wearable monitors, flexible smart clothes, industrial sensors and medical sensors will be much more effective if their antennas are lightweight and flexible – and possibly even transparent. We and our collaborators have developed a type of material that offers many more options for connecting antennas to devices – including spray-painting them on walls or clothes.
Using non-conventional methods, Christina Birkel and her colleagues in the Department of Chemistry of the TU Darmstadt produce metallic ceramics and new materials for the energy supply of the future.
The microwave oven in the laboratory of Christina Birkel, junior research group leader at the TU Darmstadt, is not only larger and significantly more expensive than the usual household device, but also more powerful and fire and explosion-proof. Birkel had the turntable and its plastic support removed. “That would have melted anyway,” she says. The chemist uses the oven for the synthesis of substances that experts call MAX phases. M stands for a transition metal, for example for titanium or vanadium, A for a main group element – usually aluminium – and X for carbon, and more rarely also nitrogen. Thus far, approximately 70 members of this family are known.
“Around the turn of the millennium, research efforts in the field of MAX phases have increased significantly,” explains Birkel. No wonder, because the materials are scratch-resistant, high-temperature stable and in many cases oxidation-resistant like a ceramic, but they also conduct electricity and sometimes have extraordinary magnetic proper ties. They are therefore also referred to as metallic ceramics. Similarly to clay minerals, MAX phases have a lamellar structure of alternating A and M-X-M layers.
