Sintering atomically thin materials with ceramics now possible

Sintering ceramics at much lower temperatures.

The schematic illustration showing the co-sintering of ceramics and 2D materials using cold sintering processing, and TEM image and energy dispersive spectroscopy (EDS) map of cold sintered 99ZnO-1Ti3C2Tx nanocomposite. The MXene nanosheets are distributed homogeneously along the ZnO grain boundaries, as seen in the TEM image and EDS map. Image: MRI/Penn State
The schematic illustration showing the co-sintering of ceramics and 2D materials using cold sintering processing, and TEM image and energy dispersive spectroscopy (EDS) map of cold sintered 99ZnO-1Ti3C2Tx nanocomposite. The MXene nanosheets are distributed homogeneously along the ZnO grain boundaries, as seen in the TEM image and EDS map. Image: MRI/Penn State

Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. The process requires high heat to compact powder materials into a solid form. Generally utilized as a part of an industry, ceramics are ordinarily compacted at temperatures of 1472 degrees Fahrenheit or higher. Some low-dimensional materials can’t get by at those temperatures.

Now, for the first time, scientists at the Penn State have created a nanocomposite of ceramics and a two-dimensional material, paving the way for new plans of nanocomposites with so many applications as solid-state batteries, thermoelectrics, varistors, catalysts, concoction sensors and significantly more.

Scientists called this process as Cold Sintering process (CSP), that 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.

The idea of trying to develop a ceramic-2D composite system was the result of a National Science Foundation workshop on the future of ceramics, organized by Lynnette Madsen, that drew 50 of the top ceramic scientists in the U.S. Yury Gogotsi, a Charles T. and Ruth M. Bach Distinguished University Professor and director of the A.J. Drexel Nanomaterials Institute, at Drexel University, heard Randall’s presentation on cold sintering and proposed a collaboration to develop a ceramic composite using a new class of two-dimensional materials, called MXenes, discovered by Gogotsi and his collaborators at Drexel. MXenes are carbide and nitride sheets a few atoms thin that possess extreme strength. Many of them are excellent metallic conductors.

Clive Randall, professor of materials science and engineering, Penn State said, “We have industry people who are already very interested in this work. They are interested in developing some new material applications with this system and, in general, using CSP to sinter nanocomposites.”

Blending even a little amount of 2D materials, for example, graphene, into a ceramic can drastically change its properties. MXene has never been utilized as a part of artistic composites. In this work, Guo and Benjamin Legum, Gogotsi’s doctoral understudy, blended 0.5 to 5.0 percent MXene into an outstanding ceramic system called zinc oxide.

The metallic MXene covered the ceramic and shaped consistent two-dimensional grain limits, which forestalled grain development, expanded the conductivity by two requests of size, changing semiconducting zinc oxide into a metallic earthenware, and multiplied hardness of the last item. The expansion of MXene likewise enhanced the capacity of zinc oxide to change warmth to power.

Randall said, “Ben came here quite frequently to work with Jing, and over time they overcame all of the problems involved with dispersing the 2D MXenes into the zinc oxide and then sintering it. This opens a whole new world incorporating 2D materials into ceramics.”

Gogotsi added, “This is the first ceramic composite containing MXene. Taking into account that about thirty MXenes with diverse properties are already available, we are opening a new chapter in research on ceramic matrix composites, with potential applications ranging from electronics to batteries and thermoelectrics.”

Other contributors to the research are research assistant professor Babak Anasori and undergraduate student Pavel Lelukh from Drexel, and Ke Wang, a staff scientist in Penn State’s Materials Research Institute.

The paper appears online in Advanced Materials.