Multi-functional nano-porous ceramics

Ceramics are stiff, hard, lightweight, and thermally stable (> 1000 °C), but are rarely used in structural components due to their brittleness. If toughened, ceramics can be an effective, light-weight alternative to existing metal components that are currently used for high-temperature applications and/or for protection coatings against heat and radiation. Recent investigations on toughening of ceramics has been mostly focused on introducing particles, fibers, and whiskers to arrest and/or deflect crack initiation and propagation. Another common toughening method is compositing with ductile phases, such as metals and polymers, but thermal stability of the resulting composites is lower. In this work, a novel toughening method is attempted by introducing nano-porosity to monolithic ceramics without degrading thermal stability. Traditionally, pores are considered as defects, but when pores are very small (<∼100 nm), the nano-pores are observed to deform locally in a non-propagating manner. Thus, fracture toughness can be potentially increased by such quasi-plastic deformations uniquely triggered by locally weak nano-porosity. In this project, we study to understand the fundamental toughening mechanisms of ceramics that arise from the introduction of nano-pores, and to study a scalable manufacturing method of these novel tough and strong ceramics. If achieved, tougher ceramics will be in high demand as improved lightweight alternatives to metal alloys in structural applications that require mechanical strength, stability in thermal and corrosive environment, such as engines, gas turbines, thermal protections, nuclear and solar energy and biomechanics.