Fabrication of mullite nano ceramic through addition of long-chain carbohydrates

Compared to common coarse-grained ceramics, nano-scaled mullite ceramics exhibit unique microstructures and mechanical properties. However, fabrication of homogeneous and ultra-fine ceramic crystals still remains a major challenge. In this study, fine-grain mullite nanocrystals with uniform particle distribution have been successfully synthesized by addition of agarose, which is a long-chain carbohydrate to the precursor. The effect of length of the carbohydrate chain on the size of mullite crystals has been investigated. The results show that long-chain carbohydrate agarose results in smaller grain size of mullite crystals as compared with glucose. Moreover, nano-scaled mullite ceramics with high hardness (18.36 GPa) and fracture toughness values (3.7 MPa m(1/2)) were obtained owing to the high relative density and small grain size. The present work highlights its potential application as long-chain carbohydrate in producing high-performance nanoceramics.