Research the Performance of Alumina Insulation Material by Freeze-Drying

The traditional method of preparation alumina insulation material includes the addition of pore-forming agent, direct foaming, foam impregnation and gel-casting. In this experiment, alpha-alumina as raw material, silica fume as an additive, Combination freeze-drying method, add pore-forming agent and direct foaming successfully prepared low-density, high strength, low thermal conductivity of alumina insulation material. Change the particle size of pore-forming agent can be get different properties of the sample. The SEM photograph was clearly observed that the hole wall dense uniform, alpha-alumina particles sufficient contact, no significant ice sublimation hole left. There are also the reasons of the sample with higher value of bending strength and compressive strength. This can make a control of porosity, as well as pore size, pore shape and pores space topology of alumina insulation material.