| The synthesis,microstructure and properties of SiAlON and composite refractories from the matrix to the products have been studied.The feasibility on the synthesis of SiAlON was analyzed under non-nitrogen atmosphere through thermodynamic calculation. On the base of the research,by using Si3N4 ,α-Al2O3 ,Al, corundum and SiC as main raw materials, the influence of the category and the quantity of the dilution on the sintering behavior and other capability parameters of SiAlON bonded corundum/SiC composites sintered under air atmosphere,under carbon reduction atmosphere and under C+SiC reduction atmosphere respectively were studied.The effect of the additives category and the sintering craft parameter on the properties,phase constitute and microstructure of SiAlON bonded corundum composites were discussed.The results show that Silicon,micro-silica,rare earth oxides Nd2O3 and CeO2 etc.can promote the sintering property of SiAlON bonded corundum composites,increase its B.P. and decrease its A.P.,thereby strength the intensity of composites. The specimens sintered under air atmosphere appear the obvious layering phenomenon, on the whole,and which can be divided into the surface protection layer, the center layer and the non-oxidized layer,SiAlON phase comes into being at about 1550℃,the crystal shape of them is columnar; The specimens sintered carbon reduction atmosphere have no obvious layering phenomenon, the formation temperature of SiAlON is about 1600℃, the crystal shape of them is acicular,fibriform or anomalous.SiAlON bonded corundum/SiC composite refractories were synthesized under both oxidation atmosphere and carbon reduction atmosphere.The results indicate that the properties of SiAlON composite refractories are better than the properties of pure corundum refractories and pure SiC refractories. The properties of refractories sintered under oxidation atmosphere are better than refractories sintered under carbon reduction atmosphere. |
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