Ti-Ni composite sub-micron powders with different compositions were prepared by vacuum melting and atomization technology.These powders,after being mixed with a solution of phenolic resin and alcohol,were applied on t...Ti-Ni composite sub-micron powders with different compositions were prepared by vacuum melting and atomization technology.These powders,after being mixed with a solution of phenolic resin and alcohol,were applied on the mold cavity wall,by which a casting-infiltration layer was introduced on the surface of ZG45 steel via reactions between the powders and molten steel under the heat released by solidification.The effects of the powders’composition and pouring temperature on the corrosion resistance of the casting-infiltration layer were studied.An optimal casting-infiltration layer with a thickness of~7 mm was obtained by infiltrating the Ti-Ni composite powders containing 35wt.%Ti to ZG45 steel pouring at 1,650℃.The casting-infiltration layer has a good metallurgic bonding with the matrix,and is mainly composed of Fe_(2)Ti phase and continuousγ-(Fe,Ni)solid solution.In the corrosive H_(2)SO_(4) solution,the corrosion potential of the casting-infiltration layer is lower than the matrix,tending to form a passivation film,which lowers the dissolution rate especially when the potential rises to 0.50 V.After dipping in the 10wt.%NaCl solution for 480 h,a lot of corrosion holes appear in the ZG45 steel matrix,while there are no obvious traces of corrosion on the casting-infiltration layer.展开更多
Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demon...Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.展开更多
Zn-ion batteries(ZIBs) have gained great attention as promising next-generation power sources, because of their low cost, enviable safety and high theoretical capacity. Recently, massive researches have been devoted t...Zn-ion batteries(ZIBs) have gained great attention as promising next-generation power sources, because of their low cost, enviable safety and high theoretical capacity. Recently, massive researches have been devoted to vanadium-based materials as cathodes in ZIBs, owing to their multiple valence states, competitive gravimetric energy density, but the capacity degradation, sluggish kinetics, low operating voltage hinder further optimization of their performance in ZIBs. This review summarizes recent progress to increase the interlayer spacing, structural stability, and the diffusion ability of the guest Zn ions, including the insertion of different ions, introduction of defects, design of diverse morphologies, the combination of other materials. We also focus on approaches to promoting the valuable performance of vanadiumbased cathodes, along with the related ongoing scientific challenges and limitations. Finally, the future perspectives and research directions of vanadium-based aqueous ZIBs are provided.展开更多
The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparati...The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparation method of tungsten alloy powder,liquid-phase method avoids the disadvantage of mechanical alloying,and the obtained powder composition is accurate and controllable,with high purity and excellent uniformity.At present,the second phase particles used for dispersion strengthening tungsten alloys are mainly composed of oxides.Oxide particles can be synthesized and precipitated in nitrate solution through in situ chemical reaction,and are uniformly distributed in composite powder by mixing and stirring.Finally,the oxide dispersion strengthened tungsten alloy(ODS-W)was obtained by reduction and sintering.Liquid-phase methods for preparing ODS-W alloys include azeotropic distillation,sol-gel methods,freeze-drying,hydrothermal synthesis,spray-drying,etc.In this paper,several liquid-phase methods for preparing tungsten alloy composite powder precursors are reviewed,and their latest research progresses are discussed.In addition,the morphologies and properties of tungsten alloys prepared by different methods are compared,which provides guidance for preparing high-performance tungsten alloys.展开更多
Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kine...Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy.The Ag NCs were prepared using a mild reducing agent via a one-pot method.The as-prepared Ag NCs were confirmed to be Ag_(49)(D-pen)_(24)(D-pen:D-penicillamine)on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics.The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy.The Ag NCs were supported on activated carbon(AC)to form Ag NCs/AC,which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min^(-1).Such a high k value indicates that the composite could outperform several previously reported catalysts.Moreover,the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle,which suggests its excellent stability.展开更多
Bulk modulus is an important mechanical property in the optimal design and selection of intermetallic compounds.In this study,bulk modulus datasets of intermetallic compounds were collected,and the features affecting ...Bulk modulus is an important mechanical property in the optimal design and selection of intermetallic compounds.In this study,bulk modulus datasets of intermetallic compounds were collected,and the features affecting the bulk modulus of intermetallics were screened via feature engineering.Three features B_(cal),dB_(avg),and TIE(corresponding to calculated bulk modulus,mean bulk modulus,and third ionization energy,respectively)were found to be the dominant factors influencing bulk modulus and can be extended to other multi-component alloys.Particularly,we predicted the bulk modulus with an accuracy of 95%using surrogate machine learning models with the selected features,and these features were also demonstrated to be effective for high-entropy alloys.Moreover,symbolic regression provided an expression for the relationship between bulk modulus and the screened features.The machine learning models provide a new approach for optimizing and predicting the bulk moduli of intermetallic compounds.展开更多
Surface modification is a fascinating way to improve the compounding effect between inorganic fillers and polymers.In this study,zirconium tungsten phosphate(ZWP) with negative thermal expansion was surface modified b...Surface modification is a fascinating way to improve the compounding effect between inorganic fillers and polymers.In this study,zirconium tungsten phosphate(ZWP) with negative thermal expansion was surface modified by silane coupling agent 3-(Trimethoxysilyl)propyl methacrylate.The effects of surface modification and the modification mechanism were analyzed in detail by X-ray diffractometer,scanning electron microscopy,Fourier transform infrared spectroscopy and thermal mechanical analysis.The surface modification could effectively reduce the thermal expansion properties of the composite.When the added amount of 3-methacryloxypropyl trimethoxysilaneSilane(trade name:KH570) is 0.50 wt%,the thermal expansion coefficient of ZWP/Aromatic polyimide composite decreased by 9.76%.The surface modification also can effectively improve the dielectric performance of aromatic polyimides.The present work provides one new way to improve the thermal expansion behavior of composites.展开更多
Continuous exploration of high-temperature structural materials is being driven by the needs of gasturbine engines capable of withstanding the high-temperature environment.Relatively low melting points of currently ap...Continuous exploration of high-temperature structural materials is being driven by the needs of gasturbine engines capable of withstanding the high-temperature environment.Relatively low melting points of currently applied superalloys restrain the further improvement of service tempe ratures.With higher melting tempe ratures above 2000℃,Mo-Si-B alloys are regarded as a new generation of ultrahightemperature structural materials.However,oxidation is a concern for the industrial application of Mo-Si-B alloys.Therefore,an in-depth understanding of the oxidation mechanisms may contribute to solving this issue,whereas relevant reviews about their recent advances are lacking.In the current work,a comprehensively systematic review about the oxidation behaviors of Mo-Si-B alloys is described for this purpose.展开更多
Increasing active metal sites is a valid approach to improve the catalytic activity of the catalyst. Co^(3+) is the main active metal site of Co-based catalysts. In this research work, through the partial transformati...Increasing active metal sites is a valid approach to improve the catalytic activity of the catalyst. Co^(3+) is the main active metal site of Co-based catalysts. In this research work, through the partial transformation of CoFePBA (CFP) via low-temperature heat treatment, the effective control of the Co^(3+)/Co^(2+) ratio has been achieved. The partial transformation strategy of low-temperature heat treatment can not only maintain the original framework structure of CFP, but also increase more active sites. The characterization results show that the CFP-200 sample obtained via heat treatment at 200 ℃ for 2 h under N2 atmosphere has the highest Co^(3+)/Co^(2+) ratio. As an oxygen evolution reaction electrocatalyst, CFP-200 shows the best electrocatalytic activity among all samples. In 1.0 mol/L KOH electrolyte, the overpotential is 312 mV at a current density of 10 mA/cm2. Therefore, low-temperature heat treatment provides an effective method for preparing low-cost and high-efficiency electrocatalysts.展开更多
基金financially supported by the National Key R&D Program of China(Grant No.2016YFB0300603)。
文摘Ti-Ni composite sub-micron powders with different compositions were prepared by vacuum melting and atomization technology.These powders,after being mixed with a solution of phenolic resin and alcohol,were applied on the mold cavity wall,by which a casting-infiltration layer was introduced on the surface of ZG45 steel via reactions between the powders and molten steel under the heat released by solidification.The effects of the powders’composition and pouring temperature on the corrosion resistance of the casting-infiltration layer were studied.An optimal casting-infiltration layer with a thickness of~7 mm was obtained by infiltrating the Ti-Ni composite powders containing 35wt.%Ti to ZG45 steel pouring at 1,650℃.The casting-infiltration layer has a good metallurgic bonding with the matrix,and is mainly composed of Fe_(2)Ti phase and continuousγ-(Fe,Ni)solid solution.In the corrosive H_(2)SO_(4) solution,the corrosion potential of the casting-infiltration layer is lower than the matrix,tending to form a passivation film,which lowers the dissolution rate especially when the potential rises to 0.50 V.After dipping in the 10wt.%NaCl solution for 480 h,a lot of corrosion holes appear in the ZG45 steel matrix,while there are no obvious traces of corrosion on the casting-infiltration layer.
基金the National Key Research and Development Program of China(No.2020YFB1713500)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials&Henan Key Laboratory of High-temperature Structural and Functional Materials,Henan University of Science and Technology(No.HKDNM2019013)+1 种基金the Student Research Training Plan of Henan University of Science and Technology(Nos.2021026 and 2021035)the Undergraduate Innovation and Entrepreneurship Training Program of Henan Province(No.S202110464005).
文摘Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.
基金financially supported by the State Key Lab of Advanced Metals and Materials (No. 2020-Z14)the Startup Funds from the Henan University of Science and Technology (Nos. 13480095 and 13480096)the National Natural Science Foundation of China (No. 52002119)。
文摘Zn-ion batteries(ZIBs) have gained great attention as promising next-generation power sources, because of their low cost, enviable safety and high theoretical capacity. Recently, massive researches have been devoted to vanadium-based materials as cathodes in ZIBs, owing to their multiple valence states, competitive gravimetric energy density, but the capacity degradation, sluggish kinetics, low operating voltage hinder further optimization of their performance in ZIBs. This review summarizes recent progress to increase the interlayer spacing, structural stability, and the diffusion ability of the guest Zn ions, including the insertion of different ions, introduction of defects, design of diverse morphologies, the combination of other materials. We also focus on approaches to promoting the valuable performance of vanadiumbased cathodes, along with the related ongoing scientific challenges and limitations. Finally, the future perspectives and research directions of vanadium-based aqueous ZIBs are provided.
基金supported by National Natural Science Foundation of China(no.U2004180)。
文摘The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparation method of tungsten alloy powder,liquid-phase method avoids the disadvantage of mechanical alloying,and the obtained powder composition is accurate and controllable,with high purity and excellent uniformity.At present,the second phase particles used for dispersion strengthening tungsten alloys are mainly composed of oxides.Oxide particles can be synthesized and precipitated in nitrate solution through in situ chemical reaction,and are uniformly distributed in composite powder by mixing and stirring.Finally,the oxide dispersion strengthened tungsten alloy(ODS-W)was obtained by reduction and sintering.Liquid-phase methods for preparing ODS-W alloys include azeotropic distillation,sol-gel methods,freeze-drying,hydrothermal synthesis,spray-drying,etc.In this paper,several liquid-phase methods for preparing tungsten alloy composite powder precursors are reviewed,and their latest research progresses are discussed.In addition,the morphologies and properties of tungsten alloys prepared by different methods are compared,which provides guidance for preparing high-performance tungsten alloys.
基金financially supported by the Huaibei Normal University Doctoral Research Start-up Funding(No.15601012)the Natural Science Foundation of Anhui Provincial Department of Education(No.KJ2019A0598)+1 种基金the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province,China(No.gxyq2019168)the Team of Superior Discipline of Chemistry(No.GFXK202108).
文摘Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy.The Ag NCs were prepared using a mild reducing agent via a one-pot method.The as-prepared Ag NCs were confirmed to be Ag_(49)(D-pen)_(24)(D-pen:D-penicillamine)on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics.The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy.The Ag NCs were supported on activated carbon(AC)to form Ag NCs/AC,which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min^(-1).Such a high k value indicates that the composite could outperform several previously reported catalysts.Moreover,the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle,which suggests its excellent stability.
基金financially supported by the National Natural Science Foundation of China(Nos.52122408,52071023,51901069 and 51901013)the Program for Science&Technology Innovation Talents in the University of Henan Province(No.22HASTIT1006)+3 种基金the Program for Central Plains Talents(No.ZYYCYU202012172)the Ministry of Education,Singapore(No.RG70/20)the PolyU Grant(No.1-W196)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials,Henan University of Science and Technology(No.HKDNM201906)。
文摘Bulk modulus is an important mechanical property in the optimal design and selection of intermetallic compounds.In this study,bulk modulus datasets of intermetallic compounds were collected,and the features affecting the bulk modulus of intermetallics were screened via feature engineering.Three features B_(cal),dB_(avg),and TIE(corresponding to calculated bulk modulus,mean bulk modulus,and third ionization energy,respectively)were found to be the dominant factors influencing bulk modulus and can be extended to other multi-component alloys.Particularly,we predicted the bulk modulus with an accuracy of 95%using surrogate machine learning models with the selected features,and these features were also demonstrated to be effective for high-entropy alloys.Moreover,symbolic regression provided an expression for the relationship between bulk modulus and the screened features.The machine learning models provide a new approach for optimizing and predicting the bulk moduli of intermetallic compounds.
基金supported by the national science foundation of china (Nos. 22071221, 21905252)the natural science foundation of Henan province (Nos. 182300410192, 212300410086)。
文摘Surface modification is a fascinating way to improve the compounding effect between inorganic fillers and polymers.In this study,zirconium tungsten phosphate(ZWP) with negative thermal expansion was surface modified by silane coupling agent 3-(Trimethoxysilyl)propyl methacrylate.The effects of surface modification and the modification mechanism were analyzed in detail by X-ray diffractometer,scanning electron microscopy,Fourier transform infrared spectroscopy and thermal mechanical analysis.The surface modification could effectively reduce the thermal expansion properties of the composite.When the added amount of 3-methacryloxypropyl trimethoxysilaneSilane(trade name:KH570) is 0.50 wt%,the thermal expansion coefficient of ZWP/Aromatic polyimide composite decreased by 9.76%.The surface modification also can effectively improve the dielectric performance of aromatic polyimides.The present work provides one new way to improve the thermal expansion behavior of composites.
基金financially supported by the National Natural Science Foundation of China(Nos.51901069 and 51901013)the China Scholarship Council(No.201808410578)+1 种基金grants from the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials,Henan University of Science and Technology(No.HKDNM201906)the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing(No.06500135)。
文摘Continuous exploration of high-temperature structural materials is being driven by the needs of gasturbine engines capable of withstanding the high-temperature environment.Relatively low melting points of currently applied superalloys restrain the further improvement of service tempe ratures.With higher melting tempe ratures above 2000℃,Mo-Si-B alloys are regarded as a new generation of ultrahightemperature structural materials.However,oxidation is a concern for the industrial application of Mo-Si-B alloys.Therefore,an in-depth understanding of the oxidation mechanisms may contribute to solving this issue,whereas relevant reviews about their recent advances are lacking.In the current work,a comprehensively systematic review about the oxidation behaviors of Mo-Si-B alloys is described for this purpose.
基金supported by the National Natural Science Foundation of China (NSFC, No. U1904215)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP)+3 种基金Natural Science Foundation of Jiangsu Province (No. BK20200044)Program for Young Changjiang Scholars of the Ministry of Education (No. Q2018270)Open Fund of National Joint Engineering Research Center for abrasion control and molding of metal materials (No. HKDNM2019010)Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Increasing active metal sites is a valid approach to improve the catalytic activity of the catalyst. Co^(3+) is the main active metal site of Co-based catalysts. In this research work, through the partial transformation of CoFePBA (CFP) via low-temperature heat treatment, the effective control of the Co^(3+)/Co^(2+) ratio has been achieved. The partial transformation strategy of low-temperature heat treatment can not only maintain the original framework structure of CFP, but also increase more active sites. The characterization results show that the CFP-200 sample obtained via heat treatment at 200 ℃ for 2 h under N2 atmosphere has the highest Co^(3+)/Co^(2+) ratio. As an oxygen evolution reaction electrocatalyst, CFP-200 shows the best electrocatalytic activity among all samples. In 1.0 mol/L KOH electrolyte, the overpotential is 312 mV at a current density of 10 mA/cm2. Therefore, low-temperature heat treatment provides an effective method for preparing low-cost and high-efficiency electrocatalysts.