Solid oxide fuel cell is attracting more attention in recent years for its lower pollution emission and high energy convert efficiency. La0.9Sr0.1Ga0.8Mg0.2O3-δis a new kind of electrolyte for intermediate temperatur...Solid oxide fuel cell is attracting more attention in recent years for its lower pollution emission and high energy convert efficiency. La0.9Sr0.1Ga0.8Mg0.2O3-δis a new kind of electrolyte for intermediate temperature SOFC. In this paper, La0.9Sr0.1Ga0.8Mg0.2O3-δ(LSGM) was prepared by solid state reaction method and formed by tape casting process to make a planar electrolyte. The appropriate amount of the dispersive was obtained by viscosity test. The densities of sintered samples increase with the increasing sintering temperature. It was found that the relative density of electrolyte can approach the value of 95 % by the isostatic pressing treatment of the green tape. The average thermal expansion coefficient of the LSGM is 11 .4×10-6 /℃at temperature range (200 ~ 1200℃). Measurements of the current-voltage and power-current characteristics of the Hi-Air cell show that the open-circuit voltage is 1.067 V at 800℃, peak current density is 0.56 A·cm -2 and the maximum power output is 0.147 W·cm -2.展开更多
Multilayer ceramic sheets composed of Li1.075Nb0.625Ti0.45O3 （LNT） layers and silver metal layers were fabricated by aqueous tape-casting method. LNT green tape was prepared using PVA （polyvinyl alcohol） as binde...Multilayer ceramic sheets composed of Li1.075Nb0.625Ti0.45O3 （LNT） layers and silver metal layers were fabricated by aqueous tape-casting method. LNT green tape was prepared using PVA （polyvinyl alcohol） as binder and ethylene glycol as plasticizer. The influence of the slurry composition on the rheological properties of the slurries and the properties of the resultant green tapes were studied. The slurry exhibited a typical shear thinning behavior. The increase in the PVA content increased the tensile strength of the tapes. The slip compositions with 5 wt pct PVA produced green tapes with satisfactory tensile strength. Ethylene glycol additions enhanced the flexibility of the green tapes but also produced a decrease in the tensile strength. Sliver inner-electrode was pasted on LNT green tapes and the sheets were stacked, pressed and sintered at 900℃ for 2 h. SEM （scanning electron microscopy） micrographs showed that the multilayer sheets were fully dense with fairly uniform microstructure and no reaction was observed between LNT and sliver layers.展开更多
The physical and electrical properties of lanthanum doped Pb(Zr,Ti)O_3 ceramic sheets(PLZT)which were prepared by tape casting method were carried out.Tape casting of lanthanum modified PZT was performed using commerc...The physical and electrical properties of lanthanum doped Pb(Zr,Ti)O_3 ceramic sheets(PLZT)which were prepared by tape casting method were carried out.Tape casting of lanthanum modified PZT was performed using commercial cellulose acetate binders and poly(ethylene glycol)plasticizers in ethanol solvent.Tapes from these slips were casted on a polymer substrate.The PLZT green tapes were stacked for 5 units and sintered in air at 1050℃ for 1 h with heating rate 5℃/min.SEM micrographs show that the tape is dense(90.26% of theoretical density)and rather uniform with grain size of approximately 1.1 ?m.The dielectric permittivity and loss tangent of PLZT ceramics as a function of temperature at 1 kHz suggest that the compounds exhibit a phase transition of diffuse type.The transition temperature(T_m)and piezoelectric coefficient(d_ 33)were 110℃ and 117 pC/N,respectively.展开更多
Conventional electrode preparation techniques of supercapacitors such as tape casting or vacuum filtration often lead to the restacking or agglomeration of twodimensional(2 D)materials.As a result,tortuous paths are c...Conventional electrode preparation techniques of supercapacitors such as tape casting or vacuum filtration often lead to the restacking or agglomeration of twodimensional(2 D)materials.As a result,tortuous paths are created for the electrolyte ions and their adsorption onto the surfaces of the active materials can be prevented.Consequently,maintaining high rate performance while increasing the thickness of electrodes has been a challenge.Herein,a facile freeze-assisted tape-casting(Fa TC)method is reported for the scalable fabrication of flexible MXene(Ti3C2Tx)supercapacitor electrode films of up to 700μm thickness,exhibiting homogeneous ice-template microstructure composed of vertically aligned MXene walls within lamellar pores.The efficient ion transport created by the internal morphology allows for fast electrochemical charge–discharge cycles and near thickness-independent performance at up to 3000 m V s-1 for films of up to 300μm in thickness.By increasing the scan rate from 20 to 10,000 m V s-1,Ti3C2Tx films of 150μm in thickness sustain 50%of its specific capacitance(222.9 F g-1).When the film thickness is doubled to 300μm,its capacitance is still retained by 60%(at 213.3 F g-1)when the scan rate is increased from 20 to3000 m V s-1,with a capacitance retention above 97.7%for over 14,000 cycles at10 A g-1.They also showed a remarkably high gravimetric and areal power density of 150 k W kg-1 at 1000 A g-1 and 667 m W cm-2 at 4444 m A cm-2,respectively.Fa TC has the potential to provide industry with a viable way to fabricate electrodes formed from 2 D materials on a large scale,while providing promising performance for use in a wide range of applications,such as flexible electronics and wearable energy storage devices.展开更多
A commercial styrene-acrylic latex binder has been investigated as a good binder for aqueous Al-2O-3 suspensions tape-casting process. This paper focuses on the forming film mechanism of latex binder, the rheological ...A commercial styrene-acrylic latex binder has been investigated as a good binder for aqueous Al-2O-3 suspensions tape-casting process. This paper focuses on the forming film mechanism of latex binder, the rheological behaviors of the suspensions, physical properties of green tapes and drying process of aqueous slurries with latex binder system. The drying process of the alumina suspensions is shown to follow a two-stage mechanism (the first stage: evaporation controlled process; and the second stage: diffusion controlled process). During the drying stage of the suspensions, the compressive force presses the latex particles and makes them be distorted, which results in cross-linking structure in contacted latex particles of the solidified tapes.A smooth-surface and high-strength green tape was fabricated by aqueous tape casting with latex binder system. The results from the SEM images of the crossing section microstructure of green tapes show that the latex is a very suitable binder for aqueous tape casting.展开更多
Prestressed SUS316 fibers/ZrO2 composite was fabricated using tape casting. Causes of cracks were analyzed by classical thermo-elastic theory and finite element method in preparation process. An optimization design wa...Prestressed SUS316 fibers/ZrO2 composite was fabricated using tape casting. Causes of cracks were analyzed by classical thermo-elastic theory and finite element method in preparation process. An optimization design was carried out on SUS316 fibers’ arrangement modes by reducing residual thermal stress. Interface topography and element distribution of composite were observed, and bending strengths were tested. Results show that cracks are generated along the direction vertical to SUS316 fibers by axial thermal stress due to different thermal expansion coefficients between SUS316 fibers and zirconia, and the average cracking space is 2 mm. No macroscopic defect is found in composite with SUS316 fibers of sine distribution, and it has better interfacial binding force since interdiffusion between SUS316 and zirconia. Bending strengths of composite with 0°/0°lamination are anisotropic and that are 385.74 MPa and 500.7 MPa respectively, but that with 0°/90°lamination is isotropic and it is 433.92 MPa. Bending strength of composite is increased obviously compared with that of zirconia because the prestress of surface is compressive stress.展开更多
Ceramic tapes, containing Al2O3-25 wt pct TiB2(B) and Al2O3-25 wt pct nano-TiC (c), have been obtained by tape casting process. Numerous tapes (about 60～80 tapes) were prepared by stacking in turn the composition (B)...Ceramic tapes, containing Al2O3-25 wt pct TiB2(B) and Al2O3-25 wt pct nano-TiC (c), have been obtained by tape casting process. Numerous tapes (about 60～80 tapes) were prepared by stacking in turn the composition (B) and (C), laminating under 10 MPa pressure, eliminating the solvent and burning out the polymer additives. The final green bodies were hot pressed at 1750℃ and 30 MPa. The composite has a bending strength of 568 MPa and a fracture toughness of 5.8 M Pa·m1/2. SEM analysis exhibits that Al2O3 particle growth was inhibited by TiC particles in C. but TiB2 particles could not hinder Al2O3 growth in B. The curves of GTA indicates that all organic additives could be removed completely above 600℃展开更多
Cordierite is a promising low-k material in mi cr oelectronic and packaging industries. When it is co-fired with the metal for re alising the multilayer circuits, temperature should be low enough to prevent the meltin...Cordierite is a promising low-k material in mi cr oelectronic and packaging industries. When it is co-fired with the metal for re alising the multilayer circuits, temperature should be low enough to prevent the melting and/or oxidising of the metal. However, this temperature is usually too low to sinter cordierite. Low melting point glass, therefore, is added to the s toichiometric cordierite to lower the sintering temperature through a liquid-si ntering process. In this research work, cordierite-based glass ceramics tapes were prepared by t ape casting from suspensions containing different solids loading and different m ean particle sizes. The optimal experimental conditions for obtaining homogenous green tapes were determined by varying the type and concentration of dispersant s and binders, the solids loading as well as the particle sizes of both cordieri te and glass. Scanning electron microscopy (SEM) and Hg porosimetry were used to characterise the green tapes. The results showed that high values of solids vol ume fractions and of the size ratio between the mean particle sizes of glass and cordierite powders favour the obtaining of homogeneous and high dense substrate s. The dielectric constant of the sintered bodies at 1 100 ℃ was around 5 and t he dissipation factor was about 0.01 at 1 MHz.展开更多
Antiferroelectric materials are promising candidates for energy-storage applications due to their double hysteresis loops,which can deliver high power density.Among the antiferroelectric materials,AgNbO_(3)is proved a...Antiferroelectric materials are promising candidates for energy-storage applications due to their double hysteresis loops,which can deliver high power density.Among the antiferroelectric materials,AgNbO_(3)is proved attractive due to its environmental-friendliness and high potential for achieving excellent energy storage performance.However,the recoverable energy storage density of AgNbO_(3)ceramics is limited by their relatively low breakdown strength.Herein,the breakdown strength of the pure AgNbO_(3)ceramics prepared using the tape casting method is enhanced to 307 kV·cm^(-1),which is,to the best of our knowledge,among the highest values reported for pure AgNbO-3bulk ceramics.The high breakdown strength may be due to its dense microstructure and good crystallinity obtained by the tape casting method and the optimized sintering temperature.Owing to its enhanced breakdown strength,AgNbO_(3)ceramics show high recoverable energy storage density of 2.8 J·cm^(-3).These results have led to the development of lead-free antiferroelectric materials and devices with high energy storage density.展开更多
Aluminum nitride(AlN)is considered one of the most desirable materials for integrated circuits and electronic packaging substrates.However,raw AlN powder reacts easily with water,forming Al(OH)3 or AlOOH on the surfac...Aluminum nitride(AlN)is considered one of the most desirable materials for integrated circuits and electronic packaging substrates.However,raw AlN powder reacts easily with water,forming Al(OH)3 or AlOOH on the surface and hindering the development of an aqueous tape-casting process for preparing AlN ceramic substrates.In this study,hydrolyzed polymaleic anhydride(HPMA)was used to modify AlN powder,which has good water solubility and dispersibility.The AlN powder was modified with 5 wt%HPMA remained stable in water for at least 90 h under magnetic stirring condition and 24 h under ball milling condition,indicating that HPMA-modified AlN powder has good resistance to hydrolysis.The action mechanism of HPMA is revealed.Firstly,–COOH of the HPMA polymer and the oxide layer on the surface of the AlN powder underwent a dehydration condensation reaction to form a compound.Secondly,long chains of the polymer further coated the surface of the AlN powder,forming an anti-hydration layer with a thickness of about 7.0 nm on the surface of the AlN particles.In addition,AlN green sheets were successfully prepared by aqueous tape casting using the HPMA-modified AlN powder without additional dispersants.Subsequently,AlN ceramic substrates were obtained by sintering at 1750℃for 4 h under an N2 atmosphere with a pressure of 0.2 MPa.The relative density and thermal conductivity were tested to be 97.3%and 122 W/(m·K),respectively.展开更多
基金Project supported by the National Natural Science Foundation of China (90510006)
文摘Solid oxide fuel cell is attracting more attention in recent years for its lower pollution emission and high energy convert efficiency. La0.9Sr0.1Ga0.8Mg0.2O3-δis a new kind of electrolyte for intermediate temperature SOFC. In this paper, La0.9Sr0.1Ga0.8Mg0.2O3-δ(LSGM) was prepared by solid state reaction method and formed by tape casting process to make a planar electrolyte. The appropriate amount of the dispersive was obtained by viscosity test. The densities of sintered samples increase with the increasing sintering temperature. It was found that the relative density of electrolyte can approach the value of 95 % by the isostatic pressing treatment of the green tape. The average thermal expansion coefficient of the LSGM is 11 .4×10-6 /℃at temperature range (200 ~ 1200℃). Measurements of the current-voltage and power-current characteristics of the Hi-Air cell show that the open-circuit voltage is 1.067 V at 800℃, peak current density is 0.56 A·cm -2 and the maximum power output is 0.147 W·cm -2.
基金supported by the Key Scientificand Technological Project of Zhejiang Province, China(2006C21071).
文摘Multilayer ceramic sheets composed of Li1.075Nb0.625Ti0.45O3 （LNT） layers and silver metal layers were fabricated by aqueous tape-casting method. LNT green tape was prepared using PVA （polyvinyl alcohol） as binder and ethylene glycol as plasticizer. The influence of the slurry composition on the rheological properties of the slurries and the properties of the resultant green tapes were studied. The slurry exhibited a typical shear thinning behavior. The increase in the PVA content increased the tensile strength of the tapes. The slip compositions with 5 wt pct PVA produced green tapes with satisfactory tensile strength. Ethylene glycol additions enhanced the flexibility of the green tapes but also produced a decrease in the tensile strength. Sliver inner-electrode was pasted on LNT green tapes and the sheets were stacked, pressed and sintered at 900℃ for 2 h. SEM （scanning electron microscopy） micrographs showed that the multilayer sheets were fully dense with fairly uniform microstructure and no reaction was observed between LNT and sliver layers.
文摘The physical and electrical properties of lanthanum doped Pb(Zr,Ti)O_3 ceramic sheets(PLZT)which were prepared by tape casting method were carried out.Tape casting of lanthanum modified PZT was performed using commercial cellulose acetate binders and poly(ethylene glycol)plasticizers in ethanol solvent.Tapes from these slips were casted on a polymer substrate.The PLZT green tapes were stacked for 5 units and sintered in air at 1050℃ for 1 h with heating rate 5℃/min.SEM micrographs show that the tape is dense(90.26% of theoretical density)and rather uniform with grain size of approximately 1.1 ?m.The dielectric permittivity and loss tangent of PLZT ceramics as a function of temperature at 1 kHz suggest that the compounds exhibit a phase transition of diffuse type.The transition temperature(T_m)and piezoelectric coefficient(d_ 33)were 110℃ and 117 pC/N,respectively.
基金supported by the Henry Royce Institute for Advanced Materials,funded through EPSRC grants EP/R00661X/1,EP/S019367/1,EP/P025021/1,and EP/P025498/1the University of Manchester for the President’s Doctoral Scholar AwardEPSRC for funding through the grants EP/R023034/1 and EP/N032888/1
文摘Conventional electrode preparation techniques of supercapacitors such as tape casting or vacuum filtration often lead to the restacking or agglomeration of twodimensional(2 D)materials.As a result,tortuous paths are created for the electrolyte ions and their adsorption onto the surfaces of the active materials can be prevented.Consequently,maintaining high rate performance while increasing the thickness of electrodes has been a challenge.Herein,a facile freeze-assisted tape-casting(Fa TC)method is reported for the scalable fabrication of flexible MXene(Ti3C2Tx)supercapacitor electrode films of up to 700μm thickness,exhibiting homogeneous ice-template microstructure composed of vertically aligned MXene walls within lamellar pores.The efficient ion transport created by the internal morphology allows for fast electrochemical charge–discharge cycles and near thickness-independent performance at up to 3000 m V s-1 for films of up to 300μm in thickness.By increasing the scan rate from 20 to 10,000 m V s-1,Ti3C2Tx films of 150μm in thickness sustain 50%of its specific capacitance(222.9 F g-1).When the film thickness is doubled to 300μm,its capacitance is still retained by 60%(at 213.3 F g-1)when the scan rate is increased from 20 to3000 m V s-1,with a capacitance retention above 97.7%for over 14,000 cycles at10 A g-1.They also showed a remarkably high gravimetric and areal power density of 150 k W kg-1 at 1000 A g-1 and 667 m W cm-2 at 4444 m A cm-2,respectively.Fa TC has the potential to provide industry with a viable way to fabricate electrodes formed from 2 D materials on a large scale,while providing promising performance for use in a wide range of applications,such as flexible electronics and wearable energy storage devices.
文摘A commercial styrene-acrylic latex binder has been investigated as a good binder for aqueous Al-2O-3 suspensions tape-casting process. This paper focuses on the forming film mechanism of latex binder, the rheological behaviors of the suspensions, physical properties of green tapes and drying process of aqueous slurries with latex binder system. The drying process of the alumina suspensions is shown to follow a two-stage mechanism (the first stage: evaporation controlled process; and the second stage: diffusion controlled process). During the drying stage of the suspensions, the compressive force presses the latex particles and makes them be distorted, which results in cross-linking structure in contacted latex particles of the solidified tapes.A smooth-surface and high-strength green tape was fabricated by aqueous tape casting with latex binder system. The results from the SEM images of the crossing section microstructure of green tapes show that the latex is a very suitable binder for aqueous tape casting.
基金Funded by the Science and Technique Research and Development Program of Shaanxi Province (No. 2007K06-13)the Science and Technique Program of Xi’an City (No. YF07061)
文摘Prestressed SUS316 fibers/ZrO2 composite was fabricated using tape casting. Causes of cracks were analyzed by classical thermo-elastic theory and finite element method in preparation process. An optimization design was carried out on SUS316 fibers’ arrangement modes by reducing residual thermal stress. Interface topography and element distribution of composite were observed, and bending strengths were tested. Results show that cracks are generated along the direction vertical to SUS316 fibers by axial thermal stress due to different thermal expansion coefficients between SUS316 fibers and zirconia, and the average cracking space is 2 mm. No macroscopic defect is found in composite with SUS316 fibers of sine distribution, and it has better interfacial binding force since interdiffusion between SUS316 and zirconia. Bending strengths of composite with 0°/0°lamination are anisotropic and that are 385.74 MPa and 500.7 MPa respectively, but that with 0°/90°lamination is isotropic and it is 433.92 MPa. Bending strength of composite is increased obviously compared with that of zirconia because the prestress of surface is compressive stress.
文摘Ceramic tapes, containing Al2O3-25 wt pct TiB2(B) and Al2O3-25 wt pct nano-TiC (c), have been obtained by tape casting process. Numerous tapes (about 60～80 tapes) were prepared by stacking in turn the composition (B) and (C), laminating under 10 MPa pressure, eliminating the solvent and burning out the polymer additives. The final green bodies were hot pressed at 1750℃ and 30 MPa. The composite has a bending strength of 568 MPa and a fracture toughness of 5.8 M Pa·m1/2. SEM analysis exhibits that Al2O3 particle growth was inhibited by TiC particles in C. but TiB2 particles could not hinder Al2O3 growth in B. The curves of GTA indicates that all organic additives could be removed completely above 600℃
文摘Cordierite is a promising low-k material in mi cr oelectronic and packaging industries. When it is co-fired with the metal for re alising the multilayer circuits, temperature should be low enough to prevent the melting and/or oxidising of the metal. However, this temperature is usually too low to sinter cordierite. Low melting point glass, therefore, is added to the s toichiometric cordierite to lower the sintering temperature through a liquid-si ntering process. In this research work, cordierite-based glass ceramics tapes were prepared by t ape casting from suspensions containing different solids loading and different m ean particle sizes. The optimal experimental conditions for obtaining homogenous green tapes were determined by varying the type and concentration of dispersant s and binders, the solids loading as well as the particle sizes of both cordieri te and glass. Scanning electron microscopy (SEM) and Hg porosimetry were used to characterise the green tapes. The results showed that high values of solids vol ume fractions and of the size ratio between the mean particle sizes of glass and cordierite powders favour the obtaining of homogeneous and high dense substrate s. The dielectric constant of the sintered bodies at 1 100 ℃ was around 5 and t he dissipation factor was about 0.01 at 1 MHz.
基金financially supported by the National Natural Science Foundation of China(Nos.52073144,51802068)the Natural Science Foundation of Hebei Province,China(No.E2021201044)+2 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK20201301)Qing Lan Project,the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(Nos.KF202005,KF202114)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Antiferroelectric materials are promising candidates for energy-storage applications due to their double hysteresis loops,which can deliver high power density.Among the antiferroelectric materials,AgNbO_(3)is proved attractive due to its environmental-friendliness and high potential for achieving excellent energy storage performance.However,the recoverable energy storage density of AgNbO_(3)ceramics is limited by their relatively low breakdown strength.Herein,the breakdown strength of the pure AgNbO_(3)ceramics prepared using the tape casting method is enhanced to 307 kV·cm^(-1),which is,to the best of our knowledge,among the highest values reported for pure AgNbO-3bulk ceramics.The high breakdown strength may be due to its dense microstructure and good crystallinity obtained by the tape casting method and the optimized sintering temperature.Owing to its enhanced breakdown strength,AgNbO_(3)ceramics show high recoverable energy storage density of 2.8 J·cm^(-3).These results have led to the development of lead-free antiferroelectric materials and devices with high energy storage density.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52102101,52267001)the Natural Science Foundation of Jiangxi Province(No.20212BAB204019).
文摘Aluminum nitride(AlN)is considered one of the most desirable materials for integrated circuits and electronic packaging substrates.However,raw AlN powder reacts easily with water,forming Al(OH)3 or AlOOH on the surface and hindering the development of an aqueous tape-casting process for preparing AlN ceramic substrates.In this study,hydrolyzed polymaleic anhydride(HPMA)was used to modify AlN powder,which has good water solubility and dispersibility.The AlN powder was modified with 5 wt%HPMA remained stable in water for at least 90 h under magnetic stirring condition and 24 h under ball milling condition,indicating that HPMA-modified AlN powder has good resistance to hydrolysis.The action mechanism of HPMA is revealed.Firstly,–COOH of the HPMA polymer and the oxide layer on the surface of the AlN powder underwent a dehydration condensation reaction to form a compound.Secondly,long chains of the polymer further coated the surface of the AlN powder,forming an anti-hydration layer with a thickness of about 7.0 nm on the surface of the AlN particles.In addition,AlN green sheets were successfully prepared by aqueous tape casting using the HPMA-modified AlN powder without additional dispersants.Subsequently,AlN ceramic substrates were obtained by sintering at 1750℃for 4 h under an N2 atmosphere with a pressure of 0.2 MPa.The relative density and thermal conductivity were tested to be 97.3%and 122 W/(m·K),respectively.
