In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenoli...In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.展开更多
High temperature oxidation behavior of two kinds of nitride bonded SiC based refractories wtls bwestigated at I 100-1 .500℃ by means of X-ray di[fractometer, scanning electronic microscopy and thermogravimetry. The r...High temperature oxidation behavior of two kinds of nitride bonded SiC based refractories wtls bwestigated at I 100-1 .500℃ by means of X-ray di[fractometer, scanning electronic microscopy and thermogravimetry. The results show that ： （1） with the temperature im＇reasing, the oxidation mass increment rote of the specimen increases.first and then. decreases, and oxidation passi＇va tion occttrs; （2） the oxidation resistance of SiAION bonded SiC refractories is superior to that of Si3N4 botlded SiC refractories ; （3） high temperature oxidtttion resuits itt the increase of compressive strength at room temperature of SiC based refractoviesiaes comlmred with specimen before oxidatiotl; the compressive strength of SIMON bonded SiC specimens oxidized at high temperatures decreases with the increase of the temperature as a result of formation amt burst of surfhce bubble, while the decrease of compressive strength of Sign4 bonded SiC specimens oxidized at high temperatures is owitng to the bwrease of the consistency of netlike crack assoeiated with cristobalite transfornuttion during cooling.展开更多
The effect of the admixtures of Al and Si metals and B4 C and MgAlON compounds on the oxidation of MgO/ Si3N4 composite refractory has been studied, which is a promising carbon free refractory for steel-making applica...The effect of the admixtures of Al and Si metals and B4 C and MgAlON compounds on the oxidation of MgO/ Si3N4 composite refractory has been studied, which is a promising carbon free refractory for steel-making application . The four kinds of admixtures can be used as anti-oxi-dants for Si3N4, but the mixture of Al and Si achieved the best result. The mixture can not only play the role as anti-oxidant, but also assist the sintering process and help form dense sintering layer, improving the property of the composite.展开更多
The refractory raw materials used in recent years were introduced,including metal and intermetallic compounds（ aluminum,silicon,ferrosilicon,etc.）,nonoxide raw materials（ Si3N4 and ferrosilicon nitride）.The develo...The refractory raw materials used in recent years were introduced,including metal and intermetallic compounds（ aluminum,silicon,ferrosilicon,etc.）,nonoxide raw materials（ Si3N4 and ferrosilicon nitride）.The developmental tendency of China＇s raw refractories in the future was also discussed.展开更多
基金supported by the National Natural Science Foundation of China(U20A20239)the Natural Science Foundation of Hubei Province(2020CFB692)the Scientific Research Fund of Hunan Provincial Education Department(18A428).
文摘In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.
文摘High temperature oxidation behavior of two kinds of nitride bonded SiC based refractories wtls bwestigated at I 100-1 .500℃ by means of X-ray di[fractometer, scanning electronic microscopy and thermogravimetry. The results show that ： （1） with the temperature im＇reasing, the oxidation mass increment rote of the specimen increases.first and then. decreases, and oxidation passi＇va tion occttrs; （2） the oxidation resistance of SiAION bonded SiC refractories is superior to that of Si3N4 botlded SiC refractories ; （3） high temperature oxidtttion resuits itt the increase of compressive strength at room temperature of SiC based refractoviesiaes comlmred with specimen before oxidatiotl; the compressive strength of SIMON bonded SiC specimens oxidized at high temperatures decreases with the increase of the temperature as a result of formation amt burst of surfhce bubble, while the decrease of compressive strength of Sign4 bonded SiC specimens oxidized at high temperatures is owitng to the bwrease of the consistency of netlike crack assoeiated with cristobalite transfornuttion during cooling.
文摘The effect of the admixtures of Al and Si metals and B4 C and MgAlON compounds on the oxidation of MgO/ Si3N4 composite refractory has been studied, which is a promising carbon free refractory for steel-making application . The four kinds of admixtures can be used as anti-oxi-dants for Si3N4, but the mixture of Al and Si achieved the best result. The mixture can not only play the role as anti-oxidant, but also assist the sintering process and help form dense sintering layer, improving the property of the composite.
文摘The refractory raw materials used in recent years were introduced,including metal and intermetallic compounds（ aluminum,silicon,ferrosilicon,etc.）,nonoxide raw materials（ Si3N4 and ferrosilicon nitride）.The developmental tendency of China＇s raw refractories in the future was also discussed.
