Dense corundum-mullite brick for blast furnace ceramic pad was prepared using white fused corundum and tabular corundum as aggregates,andalusite fine powder,sillimanite fine powder,zircon sand powder and Guangxi soil ...Dense corundum-mullite brick for blast furnace ceramic pad was prepared using white fused corundum and tabular corundum as aggregates,andalusite fine powder,sillimanite fine powder,zircon sand powder and Guangxi soil as the matrix,and phosphate as the binder,introducing different amounts ofα-alumina micropowder,tabular corundum fine powder and fused corundum powder.The properties of the prepared brick were studied.The results show that,the brick with 10 mass%of tabular corundum fine powder fired at 1560℃for 3 h in a tunnel kiln has the bulk density of 3.08 g·cm^(-3),the apparent porosity of 13.2%,the cold compressive strength of 178 MPa,the molten iron corrosion rate of 0.6%,the slag corrosion rate of 6.4%,the alkali resistance strength decreasing rate of 7.5%,and the thermal shock resistance of 32 cycles,which is both dense and of good thermal shock resistance.The slag resistance simulation test was performed,which proved that the prepared corundum-mullite brick is better than those currently supplied in the market.展开更多
In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micro...In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micropowder and fused ziconia corundum particles as the main raw materials,and pure calcium aluminate cement as the binder.The effects of the fused zirconia corundum particles addition(1-0.5 mm,0,4.5%,9%,and 18%,by mass)on the linear change rate,the apparent porosity,the cold modulus of rupture,and the thermal shock resistance of chrome corundum castables were studied,and the microstructure of the samples was analyzed.The results show that:(1)with the zirconia corundum addition increasing,the permanent linear change on heating of the samples gradually increases,the apparent porosity gradually increases,the cold modulus of rupture gradually decreases,and the thermal shock resistance gradually increases;(2)according to SEM,it can be found that the phase transformation of ZrO2 after heat treatment leads to a large number of microcracks in the material.On one hand,the cold modulus of rupture of the material is reduced;on the other hand,the thermal shock resistance of the material is improved.展开更多
Fused corundum is a rather promising raw material for preparing an alumina-based ceramic core due to its excellent high temperature resistance and chemical inertness.In this study,alumina-based ceramic cores were prep...Fused corundum is a rather promising raw material for preparing an alumina-based ceramic core due to its excellent high temperature resistance and chemical inertness.In this study,alumina-based ceramic cores were prepared using fused corundum as the matrix material,and the effect of varying silica powder contents on the properties of the alumina-based ceramic cores,including the sintering shrinkage,the flexural strength,and the high temperature deformation was investigated.The mineralization mechanisms of the silica on the alumina-based ceramic core were also analyzed.The optimum addition amount of silica in this experiment is 8% in weight.At that moment,the aluminum-based core has both a low sintering shrinkage coefficient of 0.66% and better properties:the room temperature flexural strength is 22.19 MPa,the high temperature flexural strength is 21.54 MPa,the high temperature deformation is 0.93 mm,and the residual flexural strength is 47.41 MPa.展开更多
In order to fabricate porous ceramics with good properties and proper production cost,SiC-Al2 O3 porous ceramics were prepared at 1 450 ℃ for 2 h from the powders of commercial silicon carbide and white fused corundu...In order to fabricate porous ceramics with good properties and proper production cost,SiC-Al2 O3 porous ceramics were prepared at 1 450 ℃ for 2 h from the powders of commercial silicon carbide and white fused corundum via a polymeric replication method. Effects of the mass ratio of SiC powder to white fused corundum powder（ 1 ∶ 3,1 ∶ 1 and 3 ∶ 1） on the appearance,phase composition,sintering properties and thermal shock resistance were investigated. The research results indicate that the as-prepared Si C-Al2 O3 porous ceramics have uniform pores,and their linear shrinkage ratio,apparent porosity and bulk density reach 4. 70%,67. 17%and 0. 83 g·cm-3,respectively. The thermal shock cycles from 1 400 ℃ to room temperature reach 23 including 15 cycles in air cooling condition and then 8 cycles in water cooling condition. Their main phases areα-Al2 O3 and Al6 Si2 O13 as well as a small amount of SiC and free SiO2. The as-prepared porous ceramic with the ratio of m（ SiC） ∶ m（ Al2 O3） = 1∶ 1 possesses prior comprehensive properties.展开更多
In this study,in order to evaluate the performance of homogenized bauxite,two Al_2O_3-SiC-C castables were prepared using homogenized bauxite and brown fused corundum as aggregates,respectively. 5 mass%andalusite was ...In this study,in order to evaluate the performance of homogenized bauxite,two Al_2O_3-SiC-C castables were prepared using homogenized bauxite and brown fused corundum as aggregates,respectively. 5 mass%andalusite was introduced into the two castables so as to research the effect and mechanism of andalusite in Al_2O_3-SiC-C castables. The results showed that：（1） compared with the brown fused corundum based castables,the homogenized bauxite based castables had higher cold strength after heat treatment,but lower hot modulus of rupture;（2） addition of 5 mass% andalusite could enhance the cold and hot modulus of rupture,improve the thermal shock resistance,and optimize the microstructure of specimens;（ 3） the mullitization of andalusite was not obvious in the castables fired at 1100-1400℃.展开更多
Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner c...Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner castables to investigate their influences on the flow ability, linear change on heating, bulk density, apparent porosity, cold strength, hot modulus of rupture, therm, al shock resistance, slag resistance, oxidation resistance as well as wear resistance of Al2O3 - SiC - C iron runner castables. The results show that （ 1 ） compared with the specimens with fused dense corundum, the specimens with dense sintered alumina have equivalent installation property, slag resistance and oxidation resistance, equivalent or even higher cold modulus of rupture, cold crushing strength and hot modulus of rupture, exhibiting better thermal shock resistance and cold wear resistance ; （2） adopting bimodal alumina micropowder LISAL22RABL as well as water reducers ZX2 and ZD2 can well reduce the water requirement of silica fume free castables, solving the problem of deteriorated flow ability resulted from the lack of silica fume; since the lack of silica fume avoids the formation of low melting point liquid, the hot modulus of rupture and the thermal shock resistance of the silica fume free castables are both better than those of the silica fume containing castables ; （3） the density of the castable specimens with dense sintered alumina is 4% -6% lower than that of the castable specimens with Jhsed dense corundum so the refractories consumption of one iron runner reduces by 5% by using the tastable with dense sintered alumina, which obviously reduces the cost of refractories.展开更多
文摘Dense corundum-mullite brick for blast furnace ceramic pad was prepared using white fused corundum and tabular corundum as aggregates,andalusite fine powder,sillimanite fine powder,zircon sand powder and Guangxi soil as the matrix,and phosphate as the binder,introducing different amounts ofα-alumina micropowder,tabular corundum fine powder and fused corundum powder.The properties of the prepared brick were studied.The results show that,the brick with 10 mass%of tabular corundum fine powder fired at 1560℃for 3 h in a tunnel kiln has the bulk density of 3.08 g·cm^(-3),the apparent porosity of 13.2%,the cold compressive strength of 178 MPa,the molten iron corrosion rate of 0.6%,the slag corrosion rate of 6.4%,the alkali resistance strength decreasing rate of 7.5%,and the thermal shock resistance of 32 cycles,which is both dense and of good thermal shock resistance.The slag resistance simulation test was performed,which proved that the prepared corundum-mullite brick is better than those currently supplied in the market.
文摘In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micropowder and fused ziconia corundum particles as the main raw materials,and pure calcium aluminate cement as the binder.The effects of the fused zirconia corundum particles addition(1-0.5 mm,0,4.5%,9%,and 18%,by mass)on the linear change rate,the apparent porosity,the cold modulus of rupture,and the thermal shock resistance of chrome corundum castables were studied,and the microstructure of the samples was analyzed.The results show that:(1)with the zirconia corundum addition increasing,the permanent linear change on heating of the samples gradually increases,the apparent porosity gradually increases,the cold modulus of rupture gradually decreases,and the thermal shock resistance gradually increases;(2)according to SEM,it can be found that the phase transformation of ZrO2 after heat treatment leads to a large number of microcracks in the material.On one hand,the cold modulus of rupture of the material is reduced;on the other hand,the thermal shock resistance of the material is improved.
基金financially supported by the National Science and Technology Major Project of Aero Engine and Gas Turbine(2017-Ⅶ-0008)。
文摘Fused corundum is a rather promising raw material for preparing an alumina-based ceramic core due to its excellent high temperature resistance and chemical inertness.In this study,alumina-based ceramic cores were prepared using fused corundum as the matrix material,and the effect of varying silica powder contents on the properties of the alumina-based ceramic cores,including the sintering shrinkage,the flexural strength,and the high temperature deformation was investigated.The mineralization mechanisms of the silica on the alumina-based ceramic core were also analyzed.The optimum addition amount of silica in this experiment is 8% in weight.At that moment,the aluminum-based core has both a low sintering shrinkage coefficient of 0.66% and better properties:the room temperature flexural strength is 22.19 MPa,the high temperature flexural strength is 21.54 MPa,the high temperature deformation is 0.93 mm,and the residual flexural strength is 47.41 MPa.
文摘In order to fabricate porous ceramics with good properties and proper production cost,SiC-Al2 O3 porous ceramics were prepared at 1 450 ℃ for 2 h from the powders of commercial silicon carbide and white fused corundum via a polymeric replication method. Effects of the mass ratio of SiC powder to white fused corundum powder（ 1 ∶ 3,1 ∶ 1 and 3 ∶ 1） on the appearance,phase composition,sintering properties and thermal shock resistance were investigated. The research results indicate that the as-prepared Si C-Al2 O3 porous ceramics have uniform pores,and their linear shrinkage ratio,apparent porosity and bulk density reach 4. 70%,67. 17%and 0. 83 g·cm-3,respectively. The thermal shock cycles from 1 400 ℃ to room temperature reach 23 including 15 cycles in air cooling condition and then 8 cycles in water cooling condition. Their main phases areα-Al2 O3 and Al6 Si2 O13 as well as a small amount of SiC and free SiO2. The as-prepared porous ceramic with the ratio of m（ SiC） ∶ m（ Al2 O3） = 1∶ 1 possesses prior comprehensive properties.
文摘In this study,in order to evaluate the performance of homogenized bauxite,two Al_2O_3-SiC-C castables were prepared using homogenized bauxite and brown fused corundum as aggregates,respectively. 5 mass%andalusite was introduced into the two castables so as to research the effect and mechanism of andalusite in Al_2O_3-SiC-C castables. The results showed that：（1） compared with the brown fused corundum based castables,the homogenized bauxite based castables had higher cold strength after heat treatment,but lower hot modulus of rupture;（2） addition of 5 mass% andalusite could enhance the cold and hot modulus of rupture,improve the thermal shock resistance,and optimize the microstructure of specimens;（ 3） the mullitization of andalusite was not obvious in the castables fired at 1100-1400℃.
文摘Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner castables to investigate their influences on the flow ability, linear change on heating, bulk density, apparent porosity, cold strength, hot modulus of rupture, therm, al shock resistance, slag resistance, oxidation resistance as well as wear resistance of Al2O3 - SiC - C iron runner castables. The results show that （ 1 ） compared with the specimens with fused dense corundum, the specimens with dense sintered alumina have equivalent installation property, slag resistance and oxidation resistance, equivalent or even higher cold modulus of rupture, cold crushing strength and hot modulus of rupture, exhibiting better thermal shock resistance and cold wear resistance ; （2） adopting bimodal alumina micropowder LISAL22RABL as well as water reducers ZX2 and ZD2 can well reduce the water requirement of silica fume free castables, solving the problem of deteriorated flow ability resulted from the lack of silica fume; since the lack of silica fume avoids the formation of low melting point liquid, the hot modulus of rupture and the thermal shock resistance of the silica fume free castables are both better than those of the silica fume containing castables ; （3） the density of the castable specimens with dense sintered alumina is 4% -6% lower than that of the castable specimens with Jhsed dense corundum so the refractories consumption of one iron runner reduces by 5% by using the tastable with dense sintered alumina, which obviously reduces the cost of refractories.
