Controlling interface chemistry and structure to process and toughen silicon carbide

Silicon carbide is difficult to process and the product is a brittle ceramic; however, the control of chemistry and structure at grain boundary interfaces offer the opportunity to enhance processing as well as to enhance the toughness (K-c > 9 MPa m(1/2)) and strength of this ceramic. An active chemistry and structure can alter the kinetics of interfacial motion during the processing of a structurally dense and uniform microstructure. The residual chemistry and structure at grain boundaries can control the mechanical properties both at ambient and high temperatures. The Al, B and C additives in ABC-SIC are discussed in this work, with regards to the effects of structure and chemistry on processing and properties.