Effect of Al 2O 3 particle size on the mechanical properties of alumina-based ceramics

Abstract

To study the effect of Al 2O 3 particle size on the mechanical properties of alumina-based ceramics, the monolithic nano-scale alumina ceramics and the Al 2O 3μ/Al 2O 3n/SiC n multi-scale nanocomposite materials were fabricated. The fabricating process, microstructure and the mechanical properties of the new materials were investigated in detail. The results showed that nano-scale Al 2O 3 ceramic material may be fabricated at a lower temperature with high density, and the flexural strength was improved compared with micro-scale monolithic alumina ceramics. With the optimal dispersing and fabricating technology, the intra/intergranular microstructure with well-dispersed nano-scale Al 2O 3 and nano-scale SiC was obtained in Al 2O 3μ/Al 2O 3n/SiC n composite. The improved mechanical properties may be mainly attributed to the grain fining, grain boundary reinforcement and transgranular fracture mode. The size matched effect and the different thermal expansion coefficient of the added nano-scale Al 2O 3 particles resulted in the higher mechanical properties compared with the Al 2O 3μ/SiC n composite.