The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q-1) of the alloys was measured by cantilever beam technique, and the relationship betw...The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q-1) of the alloys was measured by cantilever beam technique, and the relationship between damping capacity and strain amplitude was investigated. The results show that Al4Ce phase is formed in AZ91D alloy after adding a certain quantity of Ce contents, then as-cast microstructures of the alloys are refined. Meanwhile the damping capacity of the alloys is also improved. When the mass fraction of Ce is 0.7%, the most obvious refinement effect and the maximum damping capacity can be obtained. When the damping capacity (Q-1) is )2.728)×10-3, 61% increment can be obtained compared with unmodified AZ91D alloy. The damping capacity of the alloys is relative to strain amplitude, and the damping behavior can be explained by the theory of Granato and Lücke.展开更多
A facile and efficient ball-milling assisted sol-gel synthesis route was developed to prepare triclinic e-LiVOPO_(4)(LVOP)material with lanthanum(La)and cerium(Ce)modification individually as well as simultaneously.An...A facile and efficient ball-milling assisted sol-gel synthesis route was developed to prepare triclinic e-LiVOPO_(4)(LVOP)material with lanthanum(La)and cerium(Ce)modification individually as well as simultaneously.An LVOP/LaPO_(4)/CePO_(4)composite cathode material was successfully synthesized and results show that La and Ce co-modification noticeably improves the electrochemical performance by enhancing the high voltage capacity upon cycling,which indicates contributions from the good ionic conductors LaPO_(4)and CePO_(4).The simultaneous La and Ce modification improves the high voltage performance significantly with an increase of 50%in high voltage capacity after 20 cycles compared to pure LVOP.It also shows stabilized cycling perfo rmance with 91%capacity rete ntion after 50 cycles at 0.1 C rate,along with high-rate capability with a capacity of 83.1 mAh/g compared to the pristine sample showing the capacity of 51.6 mAh/g at a high rate of 5C.This can be attributed to the good conductivity of LaPO_(4)and CePO_(4).In addition,the LVOP/LaPO_(4)/CePO_(4)composite and the pristine LVOP give a charge transfer resistance of-105 and-212Ω,respectively,showing much lower impedance due to a combination of La and Ce addition.展开更多
As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray ...As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively. The results show that rod-like Al4Ce phase is formed in AZ91D alloy containing certain Ce content and as-cast microstructures are refined. AZ91D-0.7%Ce alloy has good grain refinement effect. The addition of Ce can reduce the corrosion rate and corrosion current density of AZ91D alloy and those of AZ91D-0.1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and 2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.展开更多
Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically inves...Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.展开更多
A novel Ce-Y/SBA-15 catalyst was prepared by modifying HY/SBA-15 microporous-mesoporous composite molecular sieve with cerium using the impregnation method. The characterization results from scanning electron microsco...A novel Ce-Y/SBA-15 catalyst was prepared by modifying HY/SBA-15 microporous-mesoporous composite molecular sieve with cerium using the impregnation method. The characterization results from scanning electron microscopy/energy dispersive X-ray dispersive spectroscopy（SEM/EDS）, transmission electron microscopy（TEM）, and X-ray fluorescence（XRF） studies indicated that the Ce-modified catalyst maintained the microporous-mesoporous structure of Y/SBA-15. The Ce ions were found to be uniformly dispersed in the pores of the molecular sieve without aggregation. The results from pyrolysis coupled-Fourier transform infrared spectroscopy（Pyridine-FTIR） and temperature programmed desorption of ammonia（NH3-TPD） showed that the loading of cerium caused the hydroxyl group in the catalyst to display stronger Bronsted acidity. The efficiency of the modified Ce-Y/SBA-15 catalyst was evaluated by using it to catalyze the synthesis of n-butyl acetate. The optimal synthesis conditions were determined by orthogonal experiments. The highest esterification yield of 94.4% was obtained when the reaction time was 2.0 h, with acid/alcohol molar ratio of 1：1.2, and catalyst loading of 10 wt.%. The results in this study demonstrated that the loading of cerium and the structure of Y/SBA-15 microporous-mesoporous composite molecular sieve helped in improving the catalytic activity of this acidic catalyst.展开更多
A series of PtCuCeMgAl quintuple hydrotalcite-like compounds with different Ce contents were synthesized by one-pot method. After calcining and reduction, CeO_2-modified Mg(Al)O-supported Pt–Cu alloy catalysts were o...A series of PtCuCeMgAl quintuple hydrotalcite-like compounds with different Ce contents were synthesized by one-pot method. After calcining and reduction, CeO_2-modified Mg(Al)O-supported Pt–Cu alloy catalysts were obtained. To understand the effect of Cu and Ce, the structure and physico-chemistry properties of the catalysts were characterized and analyzed, and the catalytic behaviors were investigated in a direct dehydrogenation of propane to propene. The results show that the Pt^(4+), Cu^(2+), and Ce^(3+) ions can be incorporated into the brucite-like layers and the Ce content significantly affects the interaction strength between Pt and Cu and the dehydrogenation performance of propane. Under the reaction conditions, the highest propane conversion(45%) with 89% selectivity to propene and a 40% propene yield were achieved with a 0.3 wt% Ce-modified PtCu/Mg(Al)O catalyst. The improved catalytic performance is related to the easy formation of Pt–Cu alloy phase, excellent resistance to sintering, and coke deposits of active components modified by CeO_2.展开更多
Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce adde...Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce added steels exhibit better pitting corrosion resistance with lower corrosion current density and bigger pitting potential compared with steel without Ce,which is mainly attributed to optimized characteristics of spherical Ce-oxysulfide inclusions with less number density,smaller average size and lower pitting corrosion susceptibility.The spherical Ce_(2)O_(2) S inclusions precipitated on the surface of CeAlO_(3) inclusions in the Ce added steels induce pits with bigger opening mouth and shallow depth,reducing their tendency of extension to go deeper due to occlusion corrosion battery in the pitting holes.Furthermore,corrosion inhibitor Ce(OH)_(3) generated by Ce_(2)O_(2) S hydration can weaken electrochemical corrosion of the matrix micro-region around the pits.To avoid harmful bigger inclusions,Ce content in steels should be regulated within reasonable range,0.015 wt% Ce in present steels effectively modified inclusions to acquire the best pitting corrosion resistance of the steels.展开更多
文摘The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q-1) of the alloys was measured by cantilever beam technique, and the relationship between damping capacity and strain amplitude was investigated. The results show that Al4Ce phase is formed in AZ91D alloy after adding a certain quantity of Ce contents, then as-cast microstructures of the alloys are refined. Meanwhile the damping capacity of the alloys is also improved. When the mass fraction of Ce is 0.7%, the most obvious refinement effect and the maximum damping capacity can be obtained. When the damping capacity (Q-1) is )2.728)×10-3, 61% increment can be obtained compared with unmodified AZ91D alloy. The damping capacity of the alloys is relative to strain amplitude, and the damping behavior can be explained by the theory of Granato and Lücke.
基金the Anhui Natural Science Foundation(1908085ME151,KJ2020A0263)China Po stdoctoral Science Foundation(2020M673404)+2 种基金Anhui Province High-end Talent Grant(DT18100044)the National Level Foreign Expert Introduction Plan(G20190219004)the National Natural Science Foundation of China(52207246)。
文摘A facile and efficient ball-milling assisted sol-gel synthesis route was developed to prepare triclinic e-LiVOPO_(4)(LVOP)material with lanthanum(La)and cerium(Ce)modification individually as well as simultaneously.An LVOP/LaPO_(4)/CePO_(4)composite cathode material was successfully synthesized and results show that La and Ce co-modification noticeably improves the electrochemical performance by enhancing the high voltage capacity upon cycling,which indicates contributions from the good ionic conductors LaPO_(4)and CePO_(4).The simultaneous La and Ce modification improves the high voltage performance significantly with an increase of 50%in high voltage capacity after 20 cycles compared to pure LVOP.It also shows stabilized cycling perfo rmance with 91%capacity rete ntion after 50 cycles at 0.1 C rate,along with high-rate capability with a capacity of 83.1 mAh/g compared to the pristine sample showing the capacity of 51.6 mAh/g at a high rate of 5C.This can be attributed to the good conductivity of LaPO_(4)and CePO_(4).In addition,the LVOP/LaPO_(4)/CePO_(4)composite and the pristine LVOP give a charge transfer resistance of-105 and-212Ω,respectively,showing much lower impedance due to a combination of La and Ce addition.
基金This work was supported by the National Natural Science Foundation of China(No.50271054)the State Educational Ministry for Scientific Research Foundation for the Returned Overseas Chinese Scholars.
文摘As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively. The results show that rod-like Al4Ce phase is formed in AZ91D alloy containing certain Ce content and as-cast microstructures are refined. AZ91D-0.7%Ce alloy has good grain refinement effect. The addition of Ce can reduce the corrosion rate and corrosion current density of AZ91D alloy and those of AZ91D-0.1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and 2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.
基金financially supported by the National Natural Science Foundation of China(No.52174363)the GDAS Project of Science and Technology Development,China(No.2019GDASYL-0203002)+2 种基金the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)the Science and Technology Project of Zhaoqing City,China(Nos.2021C003,2018K006)the Development of Key Technologies for Material and Microstructure Control of High Thermal Conductivity Casting Aluminum Alloy,China(No.2014A030313221)。
文摘Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.
基金Project supported by the Research Fund for the Doctoral Program of Higher Education(20100042110008)the Talent Scientific Research Fund of Liaoning Shihua University
文摘A novel Ce-Y/SBA-15 catalyst was prepared by modifying HY/SBA-15 microporous-mesoporous composite molecular sieve with cerium using the impregnation method. The characterization results from scanning electron microscopy/energy dispersive X-ray dispersive spectroscopy（SEM/EDS）, transmission electron microscopy（TEM）, and X-ray fluorescence（XRF） studies indicated that the Ce-modified catalyst maintained the microporous-mesoporous structure of Y/SBA-15. The Ce ions were found to be uniformly dispersed in the pores of the molecular sieve without aggregation. The results from pyrolysis coupled-Fourier transform infrared spectroscopy（Pyridine-FTIR） and temperature programmed desorption of ammonia（NH3-TPD） showed that the loading of cerium caused the hydroxyl group in the catalyst to display stronger Bronsted acidity. The efficiency of the modified Ce-Y/SBA-15 catalyst was evaluated by using it to catalyze the synthesis of n-butyl acetate. The optimal synthesis conditions were determined by orthogonal experiments. The highest esterification yield of 94.4% was obtained when the reaction time was 2.0 h, with acid/alcohol molar ratio of 1：1.2, and catalyst loading of 10 wt.%. The results in this study demonstrated that the loading of cerium and the structure of Y/SBA-15 microporous-mesoporous composite molecular sieve helped in improving the catalytic activity of this acidic catalyst.
基金supported by the National Natural Science Foundation of China(No.21776214)the Natural Science Foundation of Jiangsu Province(No.BK20161166)the State Key Laboratory of Chemical Resource Engineering
文摘A series of PtCuCeMgAl quintuple hydrotalcite-like compounds with different Ce contents were synthesized by one-pot method. After calcining and reduction, CeO_2-modified Mg(Al)O-supported Pt–Cu alloy catalysts were obtained. To understand the effect of Cu and Ce, the structure and physico-chemistry properties of the catalysts were characterized and analyzed, and the catalytic behaviors were investigated in a direct dehydrogenation of propane to propene. The results show that the Pt^(4+), Cu^(2+), and Ce^(3+) ions can be incorporated into the brucite-like layers and the Ce content significantly affects the interaction strength between Pt and Cu and the dehydrogenation performance of propane. Under the reaction conditions, the highest propane conversion(45%) with 89% selectivity to propene and a 40% propene yield were achieved with a 0.3 wt% Ce-modified PtCu/Mg(Al)O catalyst. The improved catalytic performance is related to the easy formation of Pt–Cu alloy phase, excellent resistance to sintering, and coke deposits of active components modified by CeO_2.
基金Project supported by the National Natural Science Foundation of China(U1860205,51541409)Innovation Team Cultivation Funding Project of Wuhan University of Science and Technology(2018TDX08)。
文摘Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce added steels exhibit better pitting corrosion resistance with lower corrosion current density and bigger pitting potential compared with steel without Ce,which is mainly attributed to optimized characteristics of spherical Ce-oxysulfide inclusions with less number density,smaller average size and lower pitting corrosion susceptibility.The spherical Ce_(2)O_(2) S inclusions precipitated on the surface of CeAlO_(3) inclusions in the Ce added steels induce pits with bigger opening mouth and shallow depth,reducing their tendency of extension to go deeper due to occlusion corrosion battery in the pitting holes.Furthermore,corrosion inhibitor Ce(OH)_(3) generated by Ce_(2)O_(2) S hydration can weaken electrochemical corrosion of the matrix micro-region around the pits.To avoid harmful bigger inclusions,Ce content in steels should be regulated within reasonable range,0.015 wt% Ce in present steels effectively modified inclusions to acquire the best pitting corrosion resistance of the steels.
