Study on the Influence of Different Thermal Insulation Processes on Mullite/Corundum Ceramics
To explore the influence of different insulation processes on the performance of mullite/corundum ceramics,using bauxite and coal gangue as raw materials,A3S2(3Al2O3·2SiO2)/Al2O3 ceramic embryo was prepared according to the mass ratio of 60%bauxite and 40%coal gangue.mullite/corundum ceramics were prepared by sintering with the method of constant insulation in high temperature section and fractional insulation in high and low temperature section.The change trend of bulk density,porosity and flexural strength of the prepared ceramic samples were compared and analyzed.XRD and SEM were used to characterize the phase and microstructure of the ceramic samples.The results show that the performance of A3S2/Al2O3 ceramic prepared by high and low temperature insulation is better than that prepared by constant insulation at high temperature.When the high temperature section was 1 350℃,the flexural strength of the samples obtained by the insulation process of A,A1 and A2 is 37.86,68.52 and 79.86 MPa,and the flexural strength of A1 and A2 is much higher than that of A.The main reason is that the constant insulation in the low temperature section can make the endothermic reaction in the raw material complete,and the mineral is fully transformed into the oxide for solid phase reaction in the high tem-perature section,so as to obtain better ceramic properties,and the ceramic samples prepared by A2 segmented insulation process are optimal,when the high temperature section was 1 350℃,the volume density of A2 sample is 2.23 g/cm3,the porosity is 0.26%,and the flexural strength is 79.86 MPa.
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