Fabrication processes and properties of 2-dimensional nanomaterial dispersed ceramic nanocomposites

Abstract

Ceramic materials possess outstanding physical and engineering properties, such as high melting point, hardness, strength, and good chemical inertness. However, monolithic ceramics tend to be brittle, which limits their use. Many researchers have studied methods for improving the mechanical properties of ceramics, and using added reinforcements to form a more durable composite is one of mostly studied approaches. As a reinforcement for ceramic matrix composites, graphenes have been investigated due to their outstanding aspect ratio, Young’s modulus, and strength. While several studies have investigated graphene reinforced ceramic matrix composites, the issues of inhomogeneous dispersion of graphene and weak interfacial bonding between graphene and the ceramic matrix remain as unsolved problems. There have been several studies reported on graphene/ceramic nanocomposites focusing on the mechanical properties. Graphene shows that 2-D nanomaterials can be an appropriate reinforcement for ceramic nanocomposites. Boron nitride nanoplatelet (BNNP) also have unique mechanical properties approaching that of graphene. BNNP is more stable at high temperature and has a white color, which makes it attractive to use in different areas than graphene reinforced nanocomposites, such as high-temperature applications and biomedical areas. However, there has been no research on BNNP reinforced ceramic nanocomposites. In this research, graphene and BNNP reinforced ceramic nanocomposites were fabricated for various applications. A “Molecular level mixing” process for ceramic matrix composites has been developed, which is a novel fabrication process for 2-D nanomaterials. It solves the issues of inhomogeneous dispersion of 2-D nanomaterial and weak interfacial bonding between the reinforcement and matrix. Furthermore, we firstly produced BNNP reinforced ceramic nanocomposites with enhanced mechanical properties. Toughening and lubricating mechanisms of 2-D nanomaterial in ceramic matrices were developed. Fiber-reinforcing mechanisms, such as grain refinement, pull out, and crack bridging were then investigated in the 2-D nanomaterial/ceramic matrix composites from the microstructural and formula type analysis.