Ceramic sensors could be used to monitor stress in bridges and other building infrastructure. Researchers say conductive abilities make this a promising material for self-sensing and structural health monitoring applications.
“A ceramic that becomes more or less conductive under different types of strain could lead to a new generation of sensors able to monitor their own health.
Those sensors would be embedded in structures like buildings, bridges, and aircraft.
The electrical disparity that the two types of strain—elastic and plastic—foster wasn’t obvious until researchers modeled a novel two-dimensional compound, graphene-boron-nitride (GBN).
Under elastic strain, the internal structure of a material stretched like a rubber band does not change. But the same material under plastic strain—which, in this case, stretching it far enough beyond elasticity causes—distorts its crystalline lattice. GBN, it turns out, shows different electrical properties in each case, making it a worthy candidate as a structural sensor….
Rouzbeh Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering at Rice University, and his colleagues had already determined that hexagonal-boron nitride—aka white graphene—can improve the properties of ceramics. Now, the researchers have discovered that adding graphene makes them even stronger and more versatile, along with their surprising electrical properties.
The magic lies in the ability of two-dimensional, carbon-based graphene and white graphene to bond with each other in a variety of ways, depending on their relative concentrations. Though graphene and white graphene naturally avoid water, causing them to clump, the combined nanosheets easily disperse in a slurry during the ceramic’s manufacture.
The resulting ceramics, according to the authors’ theoretical models, would become tunable semiconductors with enhanced elasticity, strength, and ductility.