FU Lvping, HUANG Ao, GU Huazhi, JIANG Hongbin, ZHANG Meijie, BAI Chen
(The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology,
Wuhan 430081, Hubei, China)
Abstract: A lightweight industrial furnace wear lining refractory can greatly reduce the energy consumption and play a decisive role in the high temperature industrial energy conservation; it is also one of the important issues that international refractory researchers focus on. The key challenge lies in the formation of closed micropores in prepared refractory materials. In this paper, firstly, the superplasticity of nano-alumina with different crystal types was investigated by means of high temperature elasticity modulus instrument and stressstrain gauge. Based on the superplasticity of nano-alumina with appropriate crystal type, lightweight alumina materials were fabricated by introducing nano-alumina sol to form a pile-up of nano-micro double scales. Experimental results showed that compared to common alumina micropowder, the nano-alumina exhibited better superplasticity. This is especially true for nano-sized γ-Al2O3, whose elasticity modulus was 3 times as high as that of common alumina micropowder. Owing to the superplasticity of nano-alumina sol, its introduction led to a lower bulk density and an increase in closed porosity and quantity of intracrystalline pores of materials. Lightweight microporous alumina with low apparent porosity, high closed porosity and small pore size could be obtained by introducing an appropriate amount of nano-alumina sol.
Key words: nano-alumina; superplasticity; nano-micro double-scale sintering; microporous alumina; closed pore