A Study On The Preparation And Properties Of Mullite-Spinel High Temperature Composite

Mullite-Spinel high temperature composite was produced by sintered mullite M70 and electrocast spinel. Mullite and spinel are all in the high temperaure area of MgO-Al2O3-SiO2 phase diagram and have good elevated temperature and chemical stability. So mullite-Spinel high temperature composite will be developed quickly with good elevated temperature properties. The sinterability of mixed fine powders of mullite and spinel and the effect of different matrix and aggregate on the microstucture and properties were investigated, the erosion-resistence to cement and steel slag was also investigated in this paper. The main conclusions as follows:1. It was proved that the content of mullite in matrix should be below 20% after the test for sintering properties.2. With the decrease of the content of mullite in matrix, the specimens became hard to be sintered. The specimen with the content of mullite in matrix is 20% was sintered at 1550℃, the specimens with the content of mullite in matrix is 10% and 5% were sintered at 1600℃. After the specimens were sintered, with the decrease of the content of mullite in matrix the bend strength decreased, but the refractoriness under load increased.3. The influence of mullite when used as aggregate in specimens on the elevated temperature properties was strong, and the influence of mullite when used as middle particle or coarse particle on the properties of specimens was different. The bend strength of the specimen in which mullite was used as middle particle was stronger than that the specimen while mullite used as coarse particle, but the refractoriness under load of the specimen in which mullite was used as middle particle was lower than the specimen with mullite as coarse particle. The bend strength and the refractoriness under load of the specimen in which mullte was used as a part of coarse particle were all higher than that the specimen with mullte the coarse particle.4. With the decrease of the content of mullite in matrix, the erosion-resistence to cements of Mullite-Spinel high temperature composite was increased.5. Mullite-Spinel high temperature composite has good erosion-resistence to steel slags.