NRTL equation is one of the equations that widely used in chemical engineering thermodynamics. The marked advantage of the NRTL equation is that it can be used for predicting the thermodynamicsproperties of multicompo...NRTL equation is one of the equations that widely used in chemical engineering thermodynamics. The marked advantage of the NRTL equation is that it can be used for predicting the thermodynamicsproperties of multicomponent systems only with the data of binary systems. However the application of it to molten alloys and the other melts in metallungy has been mrsly reported. In this article, it was used to correlate thermodynamics data of binary molten alloys which are included in the systems-Cd-Bi-Sn, Cd-Bi-Pb, Cd-Sn-Pb. The data of those ternary systems were predicted by NRTL equation. The activities of Cd in quaternary system Cd-Bi-Pb-Sn were also calculated.展开更多
The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical ...The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was eva...展开更多
A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free...A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.展开更多
The physicochemical properties of the system, such as density, surface tension, specific conductance and melting point were measured. The results were discussed.
The influence of electrolyte composition and temperature. cathodie current density as well as someadditives on preparation process of alloy Cu-Sr by molten salt electrolysis with consumable cathode was stu-died in lab...The influence of electrolyte composition and temperature. cathodie current density as well as someadditives on preparation process of alloy Cu-Sr by molten salt electrolysis with consumable cathode was stu-died in laboratory. Under optimum conditions determined experimentally. the current efficiency amountedto 70% and the master alloy contained 61% Sr After vacuum distillation or the cathodic product, metallicSr of 98% purity was obtained.展开更多
The possibility of co-deposition of Li(Ⅰ)and RE(Ⅲ)has been estimated by both theoretical analysis and experimental study on the influences of temperature and concen- tration of chloride on the deposition potential.B...The possibility of co-deposition of Li(Ⅰ)and RE(Ⅲ)has been estimated by both theoretical analysis and experimental study on the influences of temperature and concen- tration of chloride on the deposition potential.Both the electrochemical and electrolytic results clearly show that Li(Ⅰ)and RE(Ⅲ)can co-deposit on the Al-Cu electrode under selected conditions.展开更多
Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl(50 wt.%:50 wt.%) melts containing different concentrations of MgCl2 at 973 K.Cyclic voltammograms show that the und...Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl(50 wt.%:50 wt.%) melts containing different concentrations of MgCl2 at 973 K.Cyclic voltammograms show that the underpotential deposition of lithium on pre-deposited magnesium leads to the formation of liquid Mg-Li alloys.The deposition potentials of Mg(II) and Li(I) ions gradually near each other with MgCl2 concentration decreasing.Mg-Li alloys with typical α + β phases could be obtained by potentiostatic electrolysis from LiCl-KCl melts containing 5 wt.% MgCl2 at -2.25 V vs.Ag/AgCl(cathodic current density 1.70 A·cm-2) for 2.5 h.α phase, α + β phases, and β phase Mg-Li alloys with different lithium contents were obtained by potentiostatic electrolysis from LiCl-KCl melts with the different concentrations of MgCl2.The samples were characterized by X-ray diffraction and scanning electron microscopy.展开更多
Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte(Na3 AlF6-AlF3-LiF-MgF2) and oxide(Al2 O3-CuO-Y2 O3). Cathodic reduction process of Al2 O3,CuO and Y2 O3 wer...Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte(Na3 AlF6-AlF3-LiF-MgF2) and oxide(Al2 O3-CuO-Y2 O3). Cathodic reduction process of Al2 O3,CuO and Y2 O3 were analyzed by cyclic voltammetry and chronoamperometry. Components and phase composition of alloy samples prepared by potentiostatic electrolysis were characterized by scanning electron microscopy and energy dispersive spectroscopy. The results show that the Al-Cu-Y alloy can be prepared in the AIF3-NaF-5 wt%LiF-5 wt%MgF2(NaF/AlF3 = 2.2, molecular ratio) eutectic system with mixed oxide(Al2 O3-CuO-Y2 O3) through 2 h at the conditions of a temperature of 1208 K, cell voltage3.0 V, cathode current density 0.7 A/cm^2. Al(Ⅲ) and Cu(Ⅱ) ions can be reduced to zero valence Al(0) and Cu(0) directly on carbonaceous electrode surface by instantaneous nucleation, respectively, the reduction process is controlled by diffusion. The reduction potential of Y(Ⅲ) ions is close to the active ions of fluoride melts, but strengthened phase AI3 Y can be formed through electrochemical reduction and alloyed process with active Al(Ⅲ) and Cu(Ⅱ) ions, meanwhile, the Al2 Cu and Al3 Y phases are distributed at the grain boundary of Al matrix.展开更多
Al-Mn alloy coatings were electrodeposited on an iron substrate from AlCl3-NaCl-KCl molten salts with anhydrous MnCl2 enhanced by the addition of CeCl3. The microstructure and properties of the Al-Mn alloy coatings we...Al-Mn alloy coatings were electrodeposited on an iron substrate from AlCl3-NaCl-KCl molten salts with anhydrous MnCl2 enhanced by the addition of CeCl3. The microstructure and properties of the Al-Mn alloy coatings were investigated, and scanning electron microscopy, X-ray diffraction, and polarization curves were used to determine the composition, surface morphology, phase structure, and corrosion resistance of the obtained deposits. The results showed that the surface coatings were smooth, and that the crystallites were dense and uniform when 0.22 wt.% CeCl3 was added to the molten salt. An amorphous mixture of Al and Al6Mn was obtained. CeCl3 enhanced the corrosion resistance and increased the hardness of the single amorphous phase alloys. The pitting potential of the coating was approximately -1.1239 V, and its hardness was 390 kgf/mm2.展开更多
Samarium(Sm) has been widely used in making aluminum(Al)-Sm magnet alloy materials. The research team for this study developed a molten salt electrolyte system which directly produces AI-Sm alloy to replace the en...Samarium(Sm) has been widely used in making aluminum(Al)-Sm magnet alloy materials. The research team for this study developed a molten salt electrolyte system which directly produces AI-Sm alloy to replace the energy intensive conventional distillation technology. In this study, molten melt density was measured and operation conditions were optimized to separate AI-Sm alloy product from the fluoride molten melt electrolysis media based on density differences, Archimedes' principle was applied to measure density for the basic molten fluoride system(BMFS: Na_3 AlF_6-AlF_3-LiF-MgF_2)electrolysis media in the temperature range from 905 to 1055 ℃.The impact of temperature(t) and the Al_2O_3 and Sm_2O_3 addition ratio(w_((Al2O3)),w_((Sm2O3)) in the basic fluoride system on molten melt density was examined. The fluoride molten melt density relationship was determined to be:ρ=3.11701-0.00802 w_((Al2O3))+0.027825 w_((Sm2O3))-0.00117 t. The test results showed that molten density decreases with increase in temperature and Al_2O_3 addition ratio, and increases with the addition of Sm_2O_3, and/or Al_2O_3+Sm_2O_3. The separation of Al-Sm(density 2.3 g/cm^3) product melt from the BMFS melt is achieved by controlling the BMFS density to less than 2.0 g/cm3. It is concluded that the optimal operation conditions to control the BMFS molten salt density to less than 2.0 g/cm^3 are:maintain addition of Al_2O_3+Sm_2 O_3(w_((Al2O3))+w_((Sm2O3))〈9% of Na_3AlF_6,Al_2O_3/Sm_2O_3 ratio(w_((Al2O3)):w_((Sm2O3)))〉 7:3, and temperature between 965 and 995 ℃.展开更多
The corrosion behavior of an Fe-20Mn-11Al-1.8C-5Cr alloy prepared by spark plasma sintering was investigated via immersion tests in molten aluminum at 750℃ for 1 and 4 h, respectively, and a hot work steel (AlSI H13...The corrosion behavior of an Fe-20Mn-11Al-1.8C-5Cr alloy prepared by spark plasma sintering was investigated via immersion tests in molten aluminum at 750℃ for 1 and 4 h, respectively, and a hot work steel (AlSI H13) was included as a reference. The experimental results show that the corrosion rate of Fe-20Mn-11Al-1.8C-5Cr alloy is - 24% of that of H13 steel, suggesting that Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum possesses better corrosion resistance than H13 steel. Detailed analysis show that k-carbide ((Fe, Mn)3AlCx) and Cr7C3 carbide precipitated in the matrix play a key role in enhancing the corrosion resistance of Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum. Both of them show better corrosion resistance than 7-Fe matrix and H13 steel, and can also take on the role of roots in grasping the corrosion product and restrain them from spalling into the molten aluminum.展开更多
The corrosion behavior of feritic stainless steel(446)after being immersed in molten Al alloy at 750℃ for 1,2,4,and 8 h has been investigated experimentally and theoretically.The microstructure and composition distri...The corrosion behavior of feritic stainless steel(446)after being immersed in molten Al alloy at 750℃ for 1,2,4,and 8 h has been investigated experimentally and theoretically.The microstructure and composition distribution at the corrosion interface were characterized using the optical microscope,scanning electron microscope,and energy dispersive spectrometer.The results showed that Cr and Si synergistically delay the progress of corrosion at the interface of the intermetallic compounds(IMC).In the early stage of corrosion,Si element was enriched at the interface of IMC1 and IMC2,and the diffusion channels of Al element were occupied by it.However,as the corrosion progresses,Cr and Si gradually gather to form a band-like structure and coarsen,causing their hindering effect to be weakened.As the corrosion time increases,the banded structure was further aggregated and coarsened,and the inhibitory effect of Cr and Si elements on corrosion was strongly weakened.In addition,based on the cellular automata dynamics model of reaction-diffusion,the corrosion process of ferritic stainless steel in aluminum alloy melts was simulated.It is demonstrated that if there is no stabilizing effect of Cr element,the thickness of IMC will be doubled.展开更多
The electrochemical behaviour of Al, Li, and Er were investigated by electrochemical techniques, such as cyclic voltammograms, chronopotentiometric, chronoamperograms, and open circuit chronopotentiogram on molybdenum...The electrochemical behaviour of Al, Li, and Er were investigated by electrochemical techniques, such as cyclic voltammograms, chronopotentiometric, chronoamperograms, and open circuit chronopotentiogram on molybdenum electrodes. The results showed that the underpotential deposition of erbium on pre-deposited Al electrodes formed two Al-Er intermetallic compounds. The codeposition of Al, Li, Er occurred and formed Al-Li-Er alloys in LiCl-KCl-AlCl3 -Er2O3 melts at 773K. Different phases such as Al2Er, Al2Er3 and βLi phase of Al-Li-Er alloys were prepared by galvanostatic electrolysis and characterized by X-ray diffraction (XRD). Scanning electron microscopy (SEM) indicated that Er element mainly distributed at the grain boundary. ICP analyses showed that lithium and erbium contents of Al-Li-Er alloys could be controlled by AlCl3 and Er2O3 concentration and electrochemical parameters.展开更多
文摘NRTL equation is one of the equations that widely used in chemical engineering thermodynamics. The marked advantage of the NRTL equation is that it can be used for predicting the thermodynamicsproperties of multicomponent systems only with the data of binary systems. However the application of it to molten alloys and the other melts in metallungy has been mrsly reported. In this article, it was used to correlate thermodynamics data of binary molten alloys which are included in the systems-Cd-Bi-Sn, Cd-Bi-Pb, Cd-Sn-Pb. The data of those ternary systems were predicted by NRTL equation. The activities of Cd in quaternary system Cd-Bi-Pb-Sn were also calculated.
文摘The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was eva...
基金This work was supported by Postdoctoral Foundation of Northwestern Polytechnical University and Science Research FOundation o
文摘A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.
文摘The physicochemical properties of the system, such as density, surface tension, specific conductance and melting point were measured. The results were discussed.
文摘The influence of electrolyte composition and temperature. cathodie current density as well as someadditives on preparation process of alloy Cu-Sr by molten salt electrolysis with consumable cathode was stu-died in laboratory. Under optimum conditions determined experimentally. the current efficiency amountedto 70% and the master alloy contained 61% Sr After vacuum distillation or the cathodic product, metallicSr of 98% purity was obtained.
文摘The possibility of co-deposition of Li(Ⅰ)and RE(Ⅲ)has been estimated by both theoretical analysis and experimental study on the influences of temperature and concen- tration of chloride on the deposition potential.Both the electrochemical and electrolytic results clearly show that Li(Ⅰ)and RE(Ⅲ)can co-deposit on the Al-Cu electrode under selected conditions.
基金supported by the National High-Tech Research and Development Program of China (No. 2006AA03Z510)the National Natural Science Foundation of China (No. 50871033)+1 种基金the Scientific Technology Project of Heilong jiang Province, China (No. GC06A212)the fund from Harbin Municipal Science & Technology Bureau (No. 2006PFXXG006)
文摘Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl(50 wt.%:50 wt.%) melts containing different concentrations of MgCl2 at 973 K.Cyclic voltammograms show that the underpotential deposition of lithium on pre-deposited magnesium leads to the formation of liquid Mg-Li alloys.The deposition potentials of Mg(II) and Li(I) ions gradually near each other with MgCl2 concentration decreasing.Mg-Li alloys with typical α + β phases could be obtained by potentiostatic electrolysis from LiCl-KCl melts containing 5 wt.% MgCl2 at -2.25 V vs.Ag/AgCl(cathodic current density 1.70 A·cm-2) for 2.5 h.α phase, α + β phases, and β phase Mg-Li alloys with different lithium contents were obtained by potentiostatic electrolysis from LiCl-KCl melts with the different concentrations of MgCl2.The samples were characterized by X-ray diffraction and scanning electron microscopy.
基金Project supported by the National Natural Science Foundation of China(51564015)
文摘Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte(Na3 AlF6-AlF3-LiF-MgF2) and oxide(Al2 O3-CuO-Y2 O3). Cathodic reduction process of Al2 O3,CuO and Y2 O3 were analyzed by cyclic voltammetry and chronoamperometry. Components and phase composition of alloy samples prepared by potentiostatic electrolysis were characterized by scanning electron microscopy and energy dispersive spectroscopy. The results show that the Al-Cu-Y alloy can be prepared in the AIF3-NaF-5 wt%LiF-5 wt%MgF2(NaF/AlF3 = 2.2, molecular ratio) eutectic system with mixed oxide(Al2 O3-CuO-Y2 O3) through 2 h at the conditions of a temperature of 1208 K, cell voltage3.0 V, cathode current density 0.7 A/cm^2. Al(Ⅲ) and Cu(Ⅱ) ions can be reduced to zero valence Al(0) and Cu(0) directly on carbonaceous electrode surface by instantaneous nucleation, respectively, the reduction process is controlled by diffusion. The reduction potential of Y(Ⅲ) ions is close to the active ions of fluoride melts, but strengthened phase AI3 Y can be formed through electrochemical reduction and alloyed process with active Al(Ⅲ) and Cu(Ⅱ) ions, meanwhile, the Al2 Cu and Al3 Y phases are distributed at the grain boundary of Al matrix.
基金Project supported by the National Natural Science Foundation of China (51054003, 50374045)Shandong Province Natural Science Foundation (Y2007F60, ZR2011BL005)+1 种基金Shandong Province High Education Science Technology Program (J09LB59)Shandong Province Mid-life-Youth Scientists Research Encouraging Foundation (BS2009NJ007)
文摘Al-Mn alloy coatings were electrodeposited on an iron substrate from AlCl3-NaCl-KCl molten salts with anhydrous MnCl2 enhanced by the addition of CeCl3. The microstructure and properties of the Al-Mn alloy coatings were investigated, and scanning electron microscopy, X-ray diffraction, and polarization curves were used to determine the composition, surface morphology, phase structure, and corrosion resistance of the obtained deposits. The results showed that the surface coatings were smooth, and that the crystallites were dense and uniform when 0.22 wt.% CeCl3 was added to the molten salt. An amorphous mixture of Al and Al6Mn was obtained. CeCl3 enhanced the corrosion resistance and increased the hardness of the single amorphous phase alloys. The pitting potential of the coating was approximately -1.1239 V, and its hardness was 390 kgf/mm2.
基金Project supported by the National Natural Science Foundation of China(51564015,51674126)Graduate Student Innovation Special Fund of Jiangxi Province(YC2015-B064)+2 种基金Science and Technology Research Project of Jiangxi Department of Education(GJJ150664)Outstanding doctoral dissertation project fund of JXUST(YB2016007)Scientific Research Fund of JXUST(NSFJ2014-G09)
文摘Samarium(Sm) has been widely used in making aluminum(Al)-Sm magnet alloy materials. The research team for this study developed a molten salt electrolyte system which directly produces AI-Sm alloy to replace the energy intensive conventional distillation technology. In this study, molten melt density was measured and operation conditions were optimized to separate AI-Sm alloy product from the fluoride molten melt electrolysis media based on density differences, Archimedes' principle was applied to measure density for the basic molten fluoride system(BMFS: Na_3 AlF_6-AlF_3-LiF-MgF_2)electrolysis media in the temperature range from 905 to 1055 ℃.The impact of temperature(t) and the Al_2O_3 and Sm_2O_3 addition ratio(w_((Al2O3)),w_((Sm2O3)) in the basic fluoride system on molten melt density was examined. The fluoride molten melt density relationship was determined to be:ρ=3.11701-0.00802 w_((Al2O3))+0.027825 w_((Sm2O3))-0.00117 t. The test results showed that molten density decreases with increase in temperature and Al_2O_3 addition ratio, and increases with the addition of Sm_2O_3, and/or Al_2O_3+Sm_2O_3. The separation of Al-Sm(density 2.3 g/cm^3) product melt from the BMFS melt is achieved by controlling the BMFS density to less than 2.0 g/cm3. It is concluded that the optimal operation conditions to control the BMFS molten salt density to less than 2.0 g/cm^3 are:maintain addition of Al_2O_3+Sm_2 O_3(w_((Al2O3))+w_((Sm2O3))〈9% of Na_3AlF_6,Al_2O_3/Sm_2O_3 ratio(w_((Al2O3)):w_((Sm2O3)))〉 7:3, and temperature between 965 and 995 ℃.
基金This research was funded by National Natural Science Foundation of China (51271080) and Opening Project of Guangdong Key Laboratory for Advanced Metallic Materials Processing (South China University of Technology) (Grant No. G J201609).
文摘The corrosion behavior of an Fe-20Mn-11Al-1.8C-5Cr alloy prepared by spark plasma sintering was investigated via immersion tests in molten aluminum at 750℃ for 1 and 4 h, respectively, and a hot work steel (AlSI H13) was included as a reference. The experimental results show that the corrosion rate of Fe-20Mn-11Al-1.8C-5Cr alloy is - 24% of that of H13 steel, suggesting that Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum possesses better corrosion resistance than H13 steel. Detailed analysis show that k-carbide ((Fe, Mn)3AlCx) and Cr7C3 carbide precipitated in the matrix play a key role in enhancing the corrosion resistance of Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum. Both of them show better corrosion resistance than 7-Fe matrix and H13 steel, and can also take on the role of roots in grasping the corrosion product and restrain them from spalling into the molten aluminum.
文摘The corrosion behavior of feritic stainless steel(446)after being immersed in molten Al alloy at 750℃ for 1,2,4,and 8 h has been investigated experimentally and theoretically.The microstructure and composition distribution at the corrosion interface were characterized using the optical microscope,scanning electron microscope,and energy dispersive spectrometer.The results showed that Cr and Si synergistically delay the progress of corrosion at the interface of the intermetallic compounds(IMC).In the early stage of corrosion,Si element was enriched at the interface of IMC1 and IMC2,and the diffusion channels of Al element were occupied by it.However,as the corrosion progresses,Cr and Si gradually gather to form a band-like structure and coarsen,causing their hindering effect to be weakened.As the corrosion time increases,the banded structure was further aggregated and coarsened,and the inhibitory effect of Cr and Si elements on corrosion was strongly weakened.In addition,based on the cellular automata dynamics model of reaction-diffusion,the corrosion process of ferritic stainless steel in aluminum alloy melts was simulated.It is demonstrated that if there is no stabilizing effect of Cr element,the thickness of IMC will be doubled.
基金Project supported by the National 863 Project of the Ministry of Science and Technology of China(2009AA050702,2011AA03A409)National Natural Science Foundation of China(21173060)
文摘The electrochemical behaviour of Al, Li, and Er were investigated by electrochemical techniques, such as cyclic voltammograms, chronopotentiometric, chronoamperograms, and open circuit chronopotentiogram on molybdenum electrodes. The results showed that the underpotential deposition of erbium on pre-deposited Al electrodes formed two Al-Er intermetallic compounds. The codeposition of Al, Li, Er occurred and formed Al-Li-Er alloys in LiCl-KCl-AlCl3 -Er2O3 melts at 773K. Different phases such as Al2Er, Al2Er3 and βLi phase of Al-Li-Er alloys were prepared by galvanostatic electrolysis and characterized by X-ray diffraction (XRD). Scanning electron microscopy (SEM) indicated that Er element mainly distributed at the grain boundary. ICP analyses showed that lithium and erbium contents of Al-Li-Er alloys could be controlled by AlCl3 and Er2O3 concentration and electrochemical parameters.