Preparation and characterisation of closed-pore Al₂O₃-MgAl₂O₄ refractory aggregate utilising superplasticity

ABSTRACT

A novel high closed porosity Al₂O₃-MgAl₂O₄ refractory aggregate has been successfully fabricated by utilising superplasticity with Al₂O₃ and MgO as raw materials, SiC as high temperature pore-forming agent. The effects of the addition amounts of MgO and SiC on porosity, sintering behaviours, phase composition, pore size distribution and microstructure of the refractory aggregate have been investigated. The formation mechanism of the closed pore in the refractory aggregate has been discussed. The results showed that the MgO can improve the superplastic deformation ability of Al₂O₃-based ceramic at high temperature. With the content of MgO and SiC increased, the closed porosity and the pore size increased. The oxidation of SiC improved the sinterability of materials at the initial stage of sintering, and then the released gases due to the further oxidation of SiC promoted the formation of closed pores by motivating the superplastic deformation ability of Al₂O₃-based materials.

KEYWORDS:

• Refractory aggregate
• closed pore
• Al₂O₃-MgAl₂O₄
• SiC
• superplasticity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to express their gratitude for the financial support from the National Natural Science Foundation of China (No. 51404056) and the Fundamental Research Funds for the Central Universities of China (N130402015).