This is a low resolution SEM image after colloidal processing indicating partially exfoliated GPL mixed with well-dispersed Si3N4 particles. The images clearly indicate GPL decorated with Si3N4 particles; the Si3Nk4 particles are well-dispersed throughout the surface area of the sheets. Credit: ACS Publications/UA Engineering |
A
team of researchers from the University of Arizona and Rensselaer
Polytechnic Institute have increased the toughness of ceramic composites
by using graphene reinforcements that enable new fracture resistance
mechanisms in the ceramic.
The
research, lead by Assistant Professor Erica L. Corral from the
Materials Science and Engineering Department at the University of
Arizona in Tucson, and Professor Nikhil Koratkar from the Department of
Mechanical, Aerospace and Nuclear Engineering at Rensselaer Polytechnic
Institute in Troy, New York, was recently published in ACS Nano, the
monthly journal of the American Chemical Society.
“Our
work on graphene ceramic composites is the first of its kind in the
open literature and shows mechanisms for toughening using
two-dimensional graphene sheets that have yet to be seen in ceramic
composites,” said Corral. “We have significantly increased the toughness
of a ceramic and made the first observations of graphene that arrest
crack propagation and force the crack to change directions in not just
two but also three dimensions.”
These
observations will lead to a new approach for composite design using
graphene in ceramics that has not been possible using conventional fiber
reinforcements, says Corral. “The high surface area and unique
two-dimensional sheet geometry seem to be better at arresting crack
growth in ceramics over conventional fibers that are one-dimensional
reinforcements,” she said.
“This
is a classic example of highly successful interdisciplinary research
across universities that was unheard of 15 or 20 years ago, but is now
becoming critically important if we are to continue to make breakthrough
discoveries and maintain the competiveness of the United States in the
21st century,” said Prof. Koratkar of the Rensselaer Polytechnic
Institute. Koratkar met Dr. Corral at a National Science
Foundation-sponsored nanoscience conference where she delivered a talk
on her work in carbon nanotube ceramic composites.
High resolution SEM image after colloidal processing indicating partially exfoliated GPL mixed with well-dispersed Si3N4 particles. The images clearly indicate GPL decorated with Si3N4 particles; the Si3Nk4 particles are well-dispersed throughout the surface area of the sheets. |
Koratkar
was impressed with Corral’s presentation, and approached her regarding
the possibility of exploring the use of graphene to increase toughening
in brittle ceramics.
“Over
the next year we leveraged my lab’s expertise in the synthesis of bulk
quantities of graphene platelets and the expertise of Corral’s group in
ceramic composite fabrication and testing,” Koratkar said. “Our results
published in ACS Nano show the tremendous promise that graphene shows in
toughening ceramics that are notoriously brittle and prone to failure.
This work could open up an entirely new graphene ceramic nanocomposites
field of study,” he says.
This
is the first published work describing the use of graphene nanofiller
to reinforce ceramics and will appear in the journal ACS Nano. This
discovery — measured to increase fracture resistance of the resulting
ceramic nanocomposite by over 200 percent — could potentially be used
to enhance toughness for a range of ceramic materials, enabling their
widespread use in high-performance, structural applications that require
operating temperatures greater than 1,000 degrees Celsius while
maintaining structural integrity.
The
research report, “Toughening in Graphene Ceramic Composites” is
co-authored by Luke S. Walker, Victoria R. Marotto and Erica L. Corral
of the University of Arizona; and Mohammad A. Rafiee and Nikhil Koratkar
of the Rensselaer Polytechnic Institute. Funding support from the State
of Arizona, the U.S. Office of Naval Research and the U.S. National
Science Foundation Early Faculty Career Award is acknowledged.
Department of Materials Science and Engineering at the UA College of Engineering
Department of Mechanical, Aerospace and Nuclear Engineering at Rensselaer Polytechnic Institute
