An O'-Sialon-Al2O3 composite refractory was prepared by in situ reaction of Si3N4-ZrSiO4-Al2O3 mixture with fused alumina aggregates.Densification,in situreaction procedure and microstructure of the material were ...An O'-Sialon-Al2O3 composite refractory was prepared by in situ reaction of Si3N4-ZrSiO4-Al2O3 mixture with fused alumina aggregates.Densification,in situreaction procedure and microstructure of the material were investigated by means of X-ray diffraction,optical and scanning electronic microscopes and EDAX.展开更多
O'-sialon-ZrO2 composite based on the cheap commercial available zircon and silicon as raw materials can be achieved by using reac-tion nitridation method,More attention was given to the nitriding process and the ...O'-sialon-ZrO2 composite based on the cheap commercial available zircon and silicon as raw materials can be achieved by using reac-tion nitridation method,More attention was given to the nitriding process and the effect of additives on it .The experimental results show that there are two nitridation paths:one is the direct nitridation of silicon powder and the other is through the reaction between the medi-um compound ZrSi2 and the nitrogen.The effects of addition of calcia and the incorpora-tion of BN on the nitriding reaction were also investigated,the primitive experimental results demonstrated that both of calcia and BN could deteriorate the nitriding degree.展开更多
The preparation of disk shaped Mo/β'-sialon functionally gradient material(FGM) is studied.Random fractal of diffusion interface in Mo/β'-sialon FGM is also studied by variation method.
Silicon aluminum oxynitride (β-Si4Al2O2N6) powder was added into corundum castable and its FeO corrosion resistance was tested in crucible method.It was found that FeO corrosion resistance of sialon containing corund...Silicon aluminum oxynitride (β-Si4Al2O2N6) powder was added into corundum castable and its FeO corrosion resistance was tested in crucible method.It was found that FeO corrosion resistance of sialon containing corundum castables was better than that of no sialon powder added ,The optimum content of the sialon powder in castables was higher than mass of the sialon powder in castables was higher than mass 15%.Moreover,O'-sialon phase,together with β-sialon phase occurred in corundum castables heated in coke bed at 1500℃,although β-sialon powder was initially admixed into the matrix of castables.The EPMA results showed these nitrogen-containing phases located in the matrix of castables were favorable to hinder the penetration of FeO melt at high temperature in comparison with pure corundum castable.However,the flowability of corundum castable became worse originated from the sialon powder added.展开更多
Slag corrosion resistance of β-Sialon and β-Sialon-Al2O3 composites has been studied .The effects of FeO content and temperature on corrosion rate have been investi-gated by mens of dip method(static and self-r...Slag corrosion resistance of β-Sialon and β-Sialon-Al2O3 composites has been studied .The effects of FeO content and temperature on corrosion rate have been investi-gated by mens of dip method(static and self-rotating).The corrosion process and microstructural analysis.It is shown that FeO preferentially attacks β-Sialon in the composite and the protruded corundum grains would gradualy fall off into the slag.展开更多
Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was...Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was a great change of crystal phase in the similar-composition specimens singtering in air ,nitrogen and bedding protecive poder respectively,determined by XRD analysis,The subsequent evidences were also supplied by SEM.The improvement in mehanical properties of multiphase refracto-ries was observed as the amount of titania changing from 0 to 16%,The main causes maybe come from the excellent properties of high hardness and in-situ strengthening effects of the in-situ formed secondary phase,TiC or TiN.展开更多
Influence of additives and composition of the matrix on mecharical properties of Sialon bonded corundum brick with appropriate nitridation sintering curve was investigated in present paper.The phase composition and mi...Influence of additives and composition of the matrix on mecharical properties of Sialon bonded corundum brick with appropriate nitridation sintering curve was investigated in present paper.The phase composition and microstructure of the sintered specimen were analyzed by means of SEM and XRD.The results indicate that with appropriate content of ultra-fine alumina powder and aditive A,both cold and hot mechanical properties of speimens are notably enhanced.The microstructure of specimen is dense and with less porosity,Main phase of the specimen is corundum, β-sialon is also observed as the bonding phase, little impurity is observed.展开更多
In this paper,the sintering behavior of diphase β-Sialon and Al2O3/diphase β-Sialon composites has been studied and predicted by using ANN (Artificial Neural Network) method.It is found that relative density is well...In this paper,the sintering behavior of diphase β-Sialon and Al2O3/diphase β-Sialon composites has been studied and predicted by using ANN (Artificial Neural Network) method.It is found that relative density is well correlated with phase composition and sintering temperature and that the predicted values by this method are very clos to experimental results.Effectiveness of modeling has been discussed nd analyzed by presenting formulas, This may be the first attempt of applying ANN mthod in the study of refractories science and has indicated that ANN is an efficeint method.展开更多
The synthesis of β'-sialon powder by carbothermic reduction of clay followed by nitridation has been carried out.The effect of charge mixture,temperature,holding time and nitrogen flow rate on synthesis was exami...The synthesis of β'-sialon powder by carbothermic reduction of clay followed by nitridation has been carried out.The effect of charge mixture,temperature,holding time and nitrogen flow rate on synthesis was examined.The fired sample was identified by XRD and the nitrogen content of fired sample was measured.The synthesis process of sialon powder was described.展开更多
Based on introducing the quasi-parabolid rule,which indicates the relation of Gibbs free energy of formation of compounds and its compostitions,the Gibbs free energes of formation of Sialons (O'-and X-phases) were...Based on introducing the quasi-parabolid rule,which indicates the relation of Gibbs free energy of formation of compounds and its compostitions,the Gibbs free energes of formation of Sialons (O'-and X-phases) were estimated.展开更多
O′-Sialon Cermics are formed by reaction sintering of silicon nitride and silica with Al2O3(Y2O3) additive,The phase compositions of O′-Sialon Cermics are highly affected by addition of Al2O3( mul.) and are measured...O′-Sialon Cermics are formed by reaction sintering of silicon nitride and silica with Al2O3(Y2O3) additive,The phase compositions of O′-Sialon Cermics are highly affected by addition of Al2O3( mul.) and are measured by X-ray diffraction techinque.The range of additions which could impaire the stucture of O′-Sialon Cermics is given in this article.展开更多
The phase composition and microstructure of β'-Sialon/SiC whisker compostie materials were studied by means of XRD ,SEM,EDAX and HREM.Besides β'-Sialon and β-SiC as main crys-talline phases,15R AIN polytypo...The phase composition and microstructure of β'-Sialon/SiC whisker compostie materials were studied by means of XRD ,SEM,EDAX and HREM.Besides β'-Sialon and β-SiC as main crys-talline phases,15R AIN polytypoids presented in the materials,Yttrium,added in Y2O3 as sintering aid,was concetrated mainly in glassy phase,A mosaic structure of SiC whisker in β'-Sialon grains was observed,Two kinds of grain boundaries were also observed:one was a direct-contact grain boundry between β'-Sialon and β-SiC,while the other was a boundary between β'-Sialon grains wqith glassy phases.展开更多
Based on its thermodynamic analysis ,β-Sialon-Alon metastable composite ceramic has been prepared by hot pressing sintering,XRD results indicate that the product of hot pressing singering is indeed Sialon-Alon metast...Based on its thermodynamic analysis ,β-Sialon-Alon metastable composite ceramic has been prepared by hot pressing sintering,XRD results indicate that the product of hot pressing singering is indeed Sialon-Alon metastable omposite ceramic ,which is in accordance with thermodynamic展开更多
The kinetic process of slag corrosion for β-Sialon and β-Sialon-Al2O3 composites has been studied by means of dip method (static and self-rotating),The corrosion model is buitl and the formula of corrosion rate is ...The kinetic process of slag corrosion for β-Sialon and β-Sialon-Al2O3 composites has been studied by means of dip method (static and self-rotating),The corrosion model is buitl and the formula of corrosion rate is deduced,which are in accordance with experimental results.展开更多
Based on thermodynamic analysis,O'-Sialon-SiC-ZrO2 composites have been prepared by carbonthermal reduction-nitriation from natural kaolin and zircon with certain additives,The modulus of racture of well sintere...Based on thermodynamic analysis,O'-Sialon-SiC-ZrO2 composites have been prepared by carbonthermal reduction-nitriation from natural kaolin and zircon with certain additives,The modulus of racture of well sintered specimen may reach 110 MPa,The process of reaction-sintering has been discussed,The formation temperature of O'-Sialon is 1718 K by calcuation.展开更多
文摘An O'-Sialon-Al2O3 composite refractory was prepared by in situ reaction of Si3N4-ZrSiO4-Al2O3 mixture with fused alumina aggregates.Densification,in situreaction procedure and microstructure of the material were investigated by means of X-ray diffraction,optical and scanning electronic microscopes and EDAX.
文摘O'-sialon-ZrO2 composite based on the cheap commercial available zircon and silicon as raw materials can be achieved by using reac-tion nitridation method,More attention was given to the nitriding process and the effect of additives on it .The experimental results show that there are two nitridation paths:one is the direct nitridation of silicon powder and the other is through the reaction between the medi-um compound ZrSi2 and the nitrogen.The effects of addition of calcia and the incorpora-tion of BN on the nitriding reaction were also investigated,the primitive experimental results demonstrated that both of calcia and BN could deteriorate the nitriding degree.
文摘The preparation of disk shaped Mo/β'-sialon functionally gradient material(FGM) is studied.Random fractal of diffusion interface in Mo/β'-sialon FGM is also studied by variation method.
文摘Silicon aluminum oxynitride (β-Si4Al2O2N6) powder was added into corundum castable and its FeO corrosion resistance was tested in crucible method.It was found that FeO corrosion resistance of sialon containing corundum castables was better than that of no sialon powder added ,The optimum content of the sialon powder in castables was higher than mass of the sialon powder in castables was higher than mass 15%.Moreover,O'-sialon phase,together with β-sialon phase occurred in corundum castables heated in coke bed at 1500℃,although β-sialon powder was initially admixed into the matrix of castables.The EPMA results showed these nitrogen-containing phases located in the matrix of castables were favorable to hinder the penetration of FeO melt at high temperature in comparison with pure corundum castable.However,the flowability of corundum castable became worse originated from the sialon powder added.
文摘Slag corrosion resistance of β-Sialon and β-Sialon-Al2O3 composites has been studied .The effects of FeO content and temperature on corrosion rate have been investi-gated by mens of dip method(static and self-rotating).The corrosion process and microstructural analysis.It is shown that FeO preferentially attacks β-Sialon in the composite and the protruded corundum grains would gradualy fall off into the slag.
文摘Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was a great change of crystal phase in the similar-composition specimens singtering in air ,nitrogen and bedding protecive poder respectively,determined by XRD analysis,The subsequent evidences were also supplied by SEM.The improvement in mehanical properties of multiphase refracto-ries was observed as the amount of titania changing from 0 to 16%,The main causes maybe come from the excellent properties of high hardness and in-situ strengthening effects of the in-situ formed secondary phase,TiC or TiN.
文摘Influence of additives and composition of the matrix on mecharical properties of Sialon bonded corundum brick with appropriate nitridation sintering curve was investigated in present paper.The phase composition and microstructure of the sintered specimen were analyzed by means of SEM and XRD.The results indicate that with appropriate content of ultra-fine alumina powder and aditive A,both cold and hot mechanical properties of speimens are notably enhanced.The microstructure of specimen is dense and with less porosity,Main phase of the specimen is corundum, β-sialon is also observed as the bonding phase, little impurity is observed.
文摘In this paper,the sintering behavior of diphase β-Sialon and Al2O3/diphase β-Sialon composites has been studied and predicted by using ANN (Artificial Neural Network) method.It is found that relative density is well correlated with phase composition and sintering temperature and that the predicted values by this method are very clos to experimental results.Effectiveness of modeling has been discussed nd analyzed by presenting formulas, This may be the first attempt of applying ANN mthod in the study of refractories science and has indicated that ANN is an efficeint method.
文摘The synthesis of β'-sialon powder by carbothermic reduction of clay followed by nitridation has been carried out.The effect of charge mixture,temperature,holding time and nitrogen flow rate on synthesis was examined.The fired sample was identified by XRD and the nitrogen content of fired sample was measured.The synthesis process of sialon powder was described.
文摘Based on introducing the quasi-parabolid rule,which indicates the relation of Gibbs free energy of formation of compounds and its compostitions,the Gibbs free energes of formation of Sialons (O'-and X-phases) were estimated.
文摘O′-Sialon Cermics are formed by reaction sintering of silicon nitride and silica with Al2O3(Y2O3) additive,The phase compositions of O′-Sialon Cermics are highly affected by addition of Al2O3( mul.) and are measured by X-ray diffraction techinque.The range of additions which could impaire the stucture of O′-Sialon Cermics is given in this article.
文摘The phase composition and microstructure of β'-Sialon/SiC whisker compostie materials were studied by means of XRD ,SEM,EDAX and HREM.Besides β'-Sialon and β-SiC as main crys-talline phases,15R AIN polytypoids presented in the materials,Yttrium,added in Y2O3 as sintering aid,was concetrated mainly in glassy phase,A mosaic structure of SiC whisker in β'-Sialon grains was observed,Two kinds of grain boundaries were also observed:one was a direct-contact grain boundry between β'-Sialon and β-SiC,while the other was a boundary between β'-Sialon grains wqith glassy phases.
文摘Based on its thermodynamic analysis ,β-Sialon-Alon metastable composite ceramic has been prepared by hot pressing sintering,XRD results indicate that the product of hot pressing singering is indeed Sialon-Alon metastable omposite ceramic ,which is in accordance with thermodynamic
文摘The kinetic process of slag corrosion for β-Sialon and β-Sialon-Al2O3 composites has been studied by means of dip method (static and self-rotating),The corrosion model is buitl and the formula of corrosion rate is deduced,which are in accordance with experimental results.
文摘Based on thermodynamic analysis,O'-Sialon-SiC-ZrO2 composites have been prepared by carbonthermal reduction-nitriation from natural kaolin and zircon with certain additives,The modulus of racture of well sintered specimen may reach 110 MPa,The process of reaction-sintering has been discussed,The formation temperature of O'-Sialon is 1718 K by calcuation.