Al–Ga–Sn, Al–Ga–In and Al–Ga–In–Sn alloys were prepared using arc melting technique. Their microstructures were investigated by X-ray diffraction and scanning electron microscopy with energy dispersed X-ray. Ba...Al–Ga–Sn, Al–Ga–In and Al–Ga–In–Sn alloys were prepared using arc melting technique. Their microstructures were investigated by X-ray diffraction and scanning electron microscopy with energy dispersed X-ray. Based on microstructure analysis, the phase constituents of alloys at Al grain boundaries were identified. The melting points of Al grain boundary phases were measured using differential scanning calorimeter.The reactivities of Al–water at different water temperatures indicate that liquid Al grain boundary phases promote Al–water reactions of alloys. The melting points of Al grain boundary phases affect the reaction temperatures of Al–water, leading to different reaction temperatures of alloys. The measured H2 generation rate and yields of alloys are related to the compositions of alloys. The theory of microgalvanic cell is used to explain the observed different H2 generation rates of alloys.展开更多
Although already scientists in recent years have reported some experimental and theoretical results of LaNi-Al series of tritium-storage alloys, several key aspects remain the subject of considerable debate. In an eff...Although already scientists in recent years have reported some experimental and theoretical results of LaNi-Al series of tritium-storage alloys, several key aspects remain the subject of considerable debate. In an effort to interpret some of these unknowns, we have performed experimental and theoretical investigations for LaNi（5-x）Alx（x = 0, 0.25, 0.5, 0.75 and 1.0） tritium-storage alloys. Firstly, the XRD characterization indicates that the unit cell volumes of LaNi（5-x）Alx increase with Al content in alloys. Secondly, the PCisotherm measurement of LaNi（5-x）Alxalloys shows that their hydrogen absorption/desorption plateau pressures reduce with the increase of Al content while their plateau widths narrow simultaneously. The deuterium absorption/desorption plateaus have a similar trend to hydrogen＇s except for their plateaus being higher than hydrogen＇s. To explain the above experimental findings, a series of calculations based on density functional theory（DFT） and frozen phonon approach have been performed. The results manifest that：（1） the partial substitutions of Al for Ni reduce the hydrogen formation energies of LaNi（5-x）AlxH and the number of available interstitial sites, and therefore lead to the absorption/desorption plateau pressures being reduced and the plateau widths being narrowed down at the same experimental temperatures;（2） the covalent interaction between H and Ni is an important factor for estimating the stability of LaNi（5-x）Alx-H system;（3） since the calculated enthalpy change H is generally more accurate than the calculated entropy change S with respect to the corresponding experimental value for each LaNi（5-x）AlxH（or D）, the curves of H vs. hydrogen storage capacity instead of Van＇t Hoff relation, can be used to predict the experimental plateau pressures of LaNi（5-x）Alx-H（D or T） at a given temperature;（4） the hydrogen isotope effect of LaNi（5-x）Alx-H（D or T） system can be quantitatively described as a linearity relation between ⊿ZPE ＋ ⊿H^（vib） and 1/√mQ（Q = H, D, T）. From the good agreement between the predicted and experimental ln（PH/P0） and ln（PD/P0）, it is deduced that predicting ln（PT/P0） of LaNi（5-x）Alx T is feasible. The procedure of pre-computing and comparing curves of H vs. hydrogen storage capacity proposed in this paper provided an attractive tool to increase the efficiency of experimental alloying design of hydrogen（deuterium or tritium） storage materials.展开更多
A TiN interlayer with high electrical conductivity was prepared between the GH3535 alloy and the Ni coating as a diffusion barrier to elements interdiffusion with the goal of increasing the corrosion resistance of GH3...A TiN interlayer with high electrical conductivity was prepared between the GH3535 alloy and the Ni coating as a diffusion barrier to elements interdiffusion with the goal of increasing the corrosion resistance of GH3535 alloy in molten FLiNaK salt at 700℃.Results indicated that Ni coating could be directly electroplated on the TiN coated GH3535 alloy without extra conductive transition layer.TiN layer showed excellent thermal and chemical stabilities at elevated temperature in this molten salt system,without phase decomposition.The Ni/TiN composite coating was stable enough to resist corrosion in LiF-NaF-KF molten salt at 700℃.Elements interdiffusion between the substrate and Ni coating could be effectively inhibited and the corrosion resistance of the alloy was greatly enhanced.Besides,the TiN interlayer remained continuous and well adhered to the Ni coating as well as the substrate after corrosion test.展开更多
Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepare...Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepared a composite material by depositing an amorphous carbon on the graphite paper, The composite was used as a cathode to study the electrochemical performance in aluminum ion batteries. The charge/discharge results showed that the composite could exhibit a longer cycle life than the graphite paper, Electrochemical analyses demonstrated that the interface between the amorphous carbon and the graphite paper made a major contribution to the improvement of the cycling stability.展开更多
The Ni/AlN composite coating was prepared for increasing corrosion and elements interdiffusion resistance of GH3535 alloy in molten fluoride salts,and the effect of mechanical interlocking on adhesion strength between...The Ni/AlN composite coating was prepared for increasing corrosion and elements interdiffusion resistance of GH3535 alloy in molten fluoride salts,and the effect of mechanical interlocking on adhesion strength between AlN layer and nickel coating was also studied.Results indicated that the adhesion strength between AlN layer and nickel coating could be significantly enhanced through mechanical interlocking effect,which effectively prevented the nickel coating from flaking off at elevated temperature.Through an etching pre-treatment of AlN layer,the corrosion resistance of the Ni/AlN coated GH3535 alloy in molten FLiNaK salt was further improved,and elements interdiffusion between the substrate and nickel coating was completely suppressed.AlN layer as a diffusion barrier remained compact and continuous in Ni/GH3535 system after high-temperature molten salt corrosion.Moreover,a Ni-P layer consisting of Ni3P and Ni phases formed in the Ni coating after corrosion.展开更多
基金supported by the National Science Foundation of China(Grant No.51171201)the National Basic Research Program of China(No.2010CB631305)
文摘Al–Ga–Sn, Al–Ga–In and Al–Ga–In–Sn alloys were prepared using arc melting technique. Their microstructures were investigated by X-ray diffraction and scanning electron microscopy with energy dispersed X-ray. Based on microstructure analysis, the phase constituents of alloys at Al grain boundaries were identified. The melting points of Al grain boundary phases were measured using differential scanning calorimeter.The reactivities of Al–water at different water temperatures indicate that liquid Al grain boundary phases promote Al–water reactions of alloys. The melting points of Al grain boundary phases affect the reaction temperatures of Al–water, leading to different reaction temperatures of alloys. The measured H2 generation rate and yields of alloys are related to the compositions of alloys. The theory of microgalvanic cell is used to explain the observed different H2 generation rates of alloys.
基金support from the National Natural Science Foundation of China under the grant No. 51271176
文摘Although already scientists in recent years have reported some experimental and theoretical results of LaNi-Al series of tritium-storage alloys, several key aspects remain the subject of considerable debate. In an effort to interpret some of these unknowns, we have performed experimental and theoretical investigations for LaNi（5-x）Alx（x = 0, 0.25, 0.5, 0.75 and 1.0） tritium-storage alloys. Firstly, the XRD characterization indicates that the unit cell volumes of LaNi（5-x）Alx increase with Al content in alloys. Secondly, the PCisotherm measurement of LaNi（5-x）Alxalloys shows that their hydrogen absorption/desorption plateau pressures reduce with the increase of Al content while their plateau widths narrow simultaneously. The deuterium absorption/desorption plateaus have a similar trend to hydrogen＇s except for their plateaus being higher than hydrogen＇s. To explain the above experimental findings, a series of calculations based on density functional theory（DFT） and frozen phonon approach have been performed. The results manifest that：（1） the partial substitutions of Al for Ni reduce the hydrogen formation energies of LaNi（5-x）AlxH and the number of available interstitial sites, and therefore lead to the absorption/desorption plateau pressures being reduced and the plateau widths being narrowed down at the same experimental temperatures;（2） the covalent interaction between H and Ni is an important factor for estimating the stability of LaNi（5-x）Alx-H system;（3） since the calculated enthalpy change H is generally more accurate than the calculated entropy change S with respect to the corresponding experimental value for each LaNi（5-x）AlxH（or D）, the curves of H vs. hydrogen storage capacity instead of Van＇t Hoff relation, can be used to predict the experimental plateau pressures of LaNi（5-x）Alx-H（D or T） at a given temperature;（4） the hydrogen isotope effect of LaNi（5-x）Alx-H（D or T） system can be quantitatively described as a linearity relation between ⊿ZPE ＋ ⊿H^（vib） and 1/√mQ（Q = H, D, T）. From the good agreement between the predicted and experimental ln（PH/P0） and ln（PD/P0）, it is deduced that predicting ln（PT/P0） of LaNi（5-x）Alx T is feasible. The procedure of pre-computing and comparing curves of H vs. hydrogen storage capacity proposed in this paper provided an attractive tool to increase the efficiency of experimental alloying design of hydrogen（deuterium or tritium） storage materials.
文摘A TiN interlayer with high electrical conductivity was prepared between the GH3535 alloy and the Ni coating as a diffusion barrier to elements interdiffusion with the goal of increasing the corrosion resistance of GH3535 alloy in molten FLiNaK salt at 700℃.Results indicated that Ni coating could be directly electroplated on the TiN coated GH3535 alloy without extra conductive transition layer.TiN layer showed excellent thermal and chemical stabilities at elevated temperature in this molten salt system,without phase decomposition.The Ni/TiN composite coating was stable enough to resist corrosion in LiF-NaF-KF molten salt at 700℃.Elements interdiffusion between the substrate and Ni coating could be effectively inhibited and the corrosion resistance of the alloy was greatly enhanced.Besides,the TiN interlayer remained continuous and well adhered to the Ni coating as well as the substrate after corrosion test.
文摘Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepared a composite material by depositing an amorphous carbon on the graphite paper, The composite was used as a cathode to study the electrochemical performance in aluminum ion batteries. The charge/discharge results showed that the composite could exhibit a longer cycle life than the graphite paper, Electrochemical analyses demonstrated that the interface between the amorphous carbon and the graphite paper made a major contribution to the improvement of the cycling stability.
基金This work was financially supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences.
文摘The Ni/AlN composite coating was prepared for increasing corrosion and elements interdiffusion resistance of GH3535 alloy in molten fluoride salts,and the effect of mechanical interlocking on adhesion strength between AlN layer and nickel coating was also studied.Results indicated that the adhesion strength between AlN layer and nickel coating could be significantly enhanced through mechanical interlocking effect,which effectively prevented the nickel coating from flaking off at elevated temperature.Through an etching pre-treatment of AlN layer,the corrosion resistance of the Ni/AlN coated GH3535 alloy in molten FLiNaK salt was further improved,and elements interdiffusion between the substrate and nickel coating was completely suppressed.AlN layer as a diffusion barrier remained compact and continuous in Ni/GH3535 system after high-temperature molten salt corrosion.Moreover,a Ni-P layer consisting of Ni3P and Ni phases formed in the Ni coating after corrosion.
