Papers by Author: Guang Hui Wei

Abstract: 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, α-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, α-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.

Abstract: Mullite- corundum insulation material with nano crystals in matrix was fabricated by gel-casting process. The results showed that the volatilization temperature of organisms is 285°C- 600°C, there is no glass phase appeared in specimens; The mullitization begin at 1000°C, along with the raise of temperature, the quantity of mullite phase increases, especially during 1200°C- 1400°C; when the temperature is up to 1550°C, mullite becomes the main crystal phase and there are also some corundum crystals in the specimens; The specimen matrix sintered at 1550°C is consisted of nano crystals 80nm in length and 10-20nm in diameter.