The application of bauxite with low Al2O3 content has been studied in this paper and β-SiAlON has been obtained from two kinds of bauxites （Al2O3 content 68.08 mass% and 46.30 mass% respectively） by aluminum reduct...The application of bauxite with low Al2O3 content has been studied in this paper and β-SiAlON has been obtained from two kinds of bauxites （Al2O3 content 68.08 mass% and 46.30 mass% respectively） by aluminum reduction and nitridation method. The sequence of reactions has been studied using thermal analysis （TG-DTA）, X-ray diffraction （XRD） analysis and scanning electron microscopy （SEM） with EDS. Compared with carbon thermal reduction and nitridation of aluminosilicates employed presently, the reaction in the system of bauxite-Al-N2 occurs at lower temperature. β-SiAlON appears as one of the main products from 1573K and exists stably in the range of the present experimental temperature. The microstructure of β-SiAlON obtained at 1773 K is short column with 5-10μm observed by SEM.展开更多
β-Si Al ON reticular porous ceramics(Si_(6-Z)Al_(Z)O_(Z)N_(8-Z),Z=2)were prepared withα-Al_(2)O_(3),AlN and Si as raw materials and Y_(2)O_(3)as the sintering aid by the foam impregnation method.The influence of the...β-Si Al ON reticular porous ceramics(Si_(6-Z)Al_(Z)O_(Z)N_(8-Z),Z=2)were prepared withα-Al_(2)O_(3),AlN and Si as raw materials and Y_(2)O_(3)as the sintering aid by the foam impregnation method.The influence of the Y_(2)O_(3)addition(0,3%,6%and 9%,by mass)on the microstructure and the properties of the samples was studied.The results show that the Y_(2)O_(3)addition is conductive to the sintering of samples and the growth of grains.The sample added with 6%Y_(2)O_(3)has the optimal properties:the apparent porosity of 82.9%,the bulk density of 0.53 g·cm^(-3),the cold compressive strength of 1.97 MPa,and the residual cold compressive strength of 1.68 MPa after oxidation,which can be used as porous ceramic filters.展开更多
To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in a...To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in an arc furnace.The obtained fused zirconia-corundum eutectic material was processed into different particle sizes,batched according to a certain particle size distribution and mixed evenly.After pressure molding and firing at 1750℃,new zirconia-based composites were prepared.The phase composition and microstructure of the composites were analyzed.The molten glass corrosion resistance of the composites was compared with that of zirconia corundum bricks 33#and 41#.The results show that the new zirconia-based composites have a dense structure,high chemical purity without low melting point components,and good thermal shock resistance.Compared with zirconia corundum bricks 33#and 41#,after being corroded by high temperature molten glass,the new composites have no corrosion cavities,needle-like pores,defects or liquid phase infiltration,and no reaction with molten glass,showing good corrosion resistance to molten glass.展开更多
文摘The application of bauxite with low Al2O3 content has been studied in this paper and β-SiAlON has been obtained from two kinds of bauxites （Al2O3 content 68.08 mass% and 46.30 mass% respectively） by aluminum reduction and nitridation method. The sequence of reactions has been studied using thermal analysis （TG-DTA）, X-ray diffraction （XRD） analysis and scanning electron microscopy （SEM） with EDS. Compared with carbon thermal reduction and nitridation of aluminosilicates employed presently, the reaction in the system of bauxite-Al-N2 occurs at lower temperature. β-SiAlON appears as one of the main products from 1573K and exists stably in the range of the present experimental temperature. The microstructure of β-SiAlON obtained at 1773 K is short column with 5-10μm observed by SEM.
文摘β-Si Al ON reticular porous ceramics(Si_(6-Z)Al_(Z)O_(Z)N_(8-Z),Z=2)were prepared withα-Al_(2)O_(3),AlN and Si as raw materials and Y_(2)O_(3)as the sintering aid by the foam impregnation method.The influence of the Y_(2)O_(3)addition(0,3%,6%and 9%,by mass)on the microstructure and the properties of the samples was studied.The results show that the Y_(2)O_(3)addition is conductive to the sintering of samples and the growth of grains.The sample added with 6%Y_(2)O_(3)has the optimal properties:the apparent porosity of 82.9%,the bulk density of 0.53 g·cm^(-3),the cold compressive strength of 1.97 MPa,and the residual cold compressive strength of 1.68 MPa after oxidation,which can be used as porous ceramic filters.
文摘To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in an arc furnace.The obtained fused zirconia-corundum eutectic material was processed into different particle sizes,batched according to a certain particle size distribution and mixed evenly.After pressure molding and firing at 1750℃,new zirconia-based composites were prepared.The phase composition and microstructure of the composites were analyzed.The molten glass corrosion resistance of the composites was compared with that of zirconia corundum bricks 33#and 41#.The results show that the new zirconia-based composites have a dense structure,high chemical purity without low melting point components,and good thermal shock resistance.Compared with zirconia corundum bricks 33#and 41#,after being corroded by high temperature molten glass,the new composites have no corrosion cavities,needle-like pores,defects or liquid phase infiltration,and no reaction with molten glass,showing good corrosion resistance to molten glass.
