Fabrication of Microporous Corundum-Spinel Refractory Castables by Foam-Gelcasting Methods

Microporous corundum-spinel castables with high strength and low thermal conductivity have been fabricated by foam-gelcasting methods. A systematical investigation on different properties of samples, such as porosity, pore size distribution, thermal conductivity, cold modulus of rupture, and cold crushing strength has been taken in this paper, and scanning electron microscopy (SEM) was used to characterize the microstructure of samples. Results show that the average pore size increases correspondingly when the content of foaming agent increases from 0 to 2.0 wt.%. It was found that when the content of the foaming agent is up to 1.5 wt.%, the thermal conductivity, cold modulus of rupture, and cold crushing strength of samples were 0.751 W/mK at 1000 °C, 30.5, and 136 MPa, respectively.