The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and Mo...The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and MoS2 on the properties of composites was analyzed through a comparative experiment by adding Ni and MoS2 separately.The results show that the nickel wrapping around the MoS2 particles decreases the reaction rate of MoS2 with the copper matrix,and greatly improves the bonding of the matrix.The composites with 12 wt.%Ni-coated MoS2(C12)show the optimum performance including the mechanical properties and tribological behaviors.Under oil lubrication conditions,the friction coefficient is 0.0075 with a pressure of 8 MPa and a linear velocity of 0.25 m/s.The average dry friction coefficient,sliding against 40Cr steel disc,is measured to be 0.1769 when the linear velocity and pressure are 0.25 m/s and 4 MPa,respectively.展开更多
The purpose of this paper is to review the current state of development of new composite materials for advanced aircraft engines. The advantages and disadvantages of Ti-base.NiAl-base, and MoSi_2-base composites as re...The purpose of this paper is to review the current state of development of new composite materials for advanced aircraft engines. The advantages and disadvantages of Ti-base.NiAl-base, and MoSi_2-base composites as replacements for today's Ni-base superalloys are discussed from the standpoint of key technical issues. current status, and future directions. Results describing progress in both improved understanding of the mechanisms of deformation and fracture, and improved material performance will be covered.展开更多
ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition...ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB_(2)-based ceramic samples were investigated.The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB_(2)-based ceramic composites and improve the physical properties of the materials.The flexural strength of the ceramic sample with 8 vol.%nano-graphite reached 418.54 MPa,which was 53.14% higher than that of ZrB_(2)-SiC ceramic material(273.31 MPa),and its oxidation resistance was also significantly improved.It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB_(2)-SiC ceramic composites.Via prolonging its service life in application and promoting the development of ZrB_(2)-based ceramic composites,it is of great significance for clean steel smelting.展开更多
The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,...The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,a tri-layered TGO scale,comprising cristobalite,Hf-doped SiO_(2)glass,and particle-reinforced Hf-Si-O glass,was formed during the oxidation of MoSi_(2)/HfO_(2)duplex EBCs.The incorporation of gradient Hf doping and HfO_(2)/HfSiO_(4)particle reinforcement effectively suppressed the crystallization and phase transition of SiO_(2)and mitigated the internal stress within the EBCs,generating a crack-blocking effect.This effect prevented the scale of the TGOs from further channel crack propagation,enabling the SiC substrate with no detectable corrosion after 200 h of exposure at 1500℃in steam,even when the TGOs thickness reached 24.5μm.This work presents a novel strategy to simultaneously extend the service lifetime and enhance the high-temperature capability of EBCs through the tailored design of TGO composition and structure.展开更多
In recent years,significant progress has been achieved in the creation of innovative functional materials for energy storage and conversion.Due to their distinct physicochemical characteristics,ultrathin nanosheets co...In recent years,significant progress has been achieved in the creation of innovative functional materials for energy storage and conversion.Due to their distinct physicochemical characteristics,ultrathin nanosheets composed of common layered transition metal sulfide materials(MoS2)have demonstrated promise as high-capacity anode materials for lithium-ion batteries(LIBs).Nevertheless,their practical application is severely limited by the tendency of monolayer nanosheets to restack due to strong van der Waals forces,dramatic volume changes during successive cycles,and low intrinsic conductivity.Recent research advances have shown that composite structures and nanowire morphologies with specific morphologies effectively overcome these issues.This paper reviews the recent research progress on molybdenum disulfide-based composites as anode materials for LIBs and discusses in detail the struc-tural characteristics of pure molybdenum disulfide and other composite forms of molybdenum disulfide.In addition,the phase engineering,defect engineering,and lithium storage mechanisms of molybdenum disulfide and the synthesis of molybdenum disulfide-based nanocomposites by different preparation methods are focused on.Finally,we review the design(structure),recent developments,and challenges of novel anode materials and consider their electrochemical performance in Li-ion batteries.展开更多
Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecti...Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecting different hazardous gases.TiO_(2) nanomaterials are promising candidates with great potential and excellent per-formance in gas sensor applications,such as hydrogen,acetone,ammonia,and ethanol detection.This review begins with a detailed discussion of the di ferent dimensional morphologies of TiO_(2),whitch affect the gas sensing performance of TiO_(2) sensors.The diverse morphologies of TiO_(2) can easily be tuned by regulating the manufacturing conditions.Meanwhile,they exhibit unique characteristics for detecting gases,including large specific suface area,superior elecron tr ansport rates,extraordinary pemmeability,and active reaction sites,which offer new opportunities to improve the gas sensing properties.In addition,a variety of efforts have been made to functional TiO_(2) nanomaterials to further enhance sensing properties,including TiO_(2)-based composites and light-assisted gas sensors.The enhanced gas sensing mechanisms of multi-component composite nano-materials based on TiO_(2) include loaded noble metals,doped elements,constructed heterojunctions,and com-pounded with other functional materials.Finally,several studies have been summarized to demonstate the compar ative sensing properties of TiO_(2)-based gas sensors.展开更多
TWC-equipped exhausts are widely used in gasoline-fueled vehicles to meet stringent emission regulations. The main components in TWCs are precious metals such as palladium (Pd), platinum (Pt), and rhodium (Rh) as the ...TWC-equipped exhausts are widely used in gasoline-fueled vehicles to meet stringent emission regulations. The main components in TWCs are precious metals such as palladium (Pd), platinum (Pt), and rhodium (Rh) as the active component, and inorganic oxides such as γ-alumina (Al 2 O 3 ), ceria (CeO 2 ), zirconia (ZrO 2 ) and ceria-zirconia (CeO 2-ZrO 2 ) are used as the support. Interaction of precious metals and support plays an important role in the thermal stability and catalytic performance of TWCs. The support can improve the dispersion of precious metals and suppress the sintering of precious metals at high temperature. In the same, precious metals can also enhance the redox performance and oxygen storage capacity of support. This paper reviews the reaction phenomenon and mechanism of precious metals (Pt, Pd, Rh) and supports such as Al 2 O 3 , CeO 2-based composite oxides.展开更多
基金Projects(51371099,51501091)supported by the National Natural Science Foundation of China。
文摘The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and MoS2 on the properties of composites was analyzed through a comparative experiment by adding Ni and MoS2 separately.The results show that the nickel wrapping around the MoS2 particles decreases the reaction rate of MoS2 with the copper matrix,and greatly improves the bonding of the matrix.The composites with 12 wt.%Ni-coated MoS2(C12)show the optimum performance including the mechanical properties and tribological behaviors.Under oil lubrication conditions,the friction coefficient is 0.0075 with a pressure of 8 MPa and a linear velocity of 0.25 m/s.The average dry friction coefficient,sliding against 40Cr steel disc,is measured to be 0.1769 when the linear velocity and pressure are 0.25 m/s and 4 MPa,respectively.
基金supported by the Funding of National Key Laboratory,the Pre-Research Funding,China(No.6142907200301)the Key Laboratory of Lightweight High Strength Structural Materials and State Key Laboratory of Powder Metallurgy in Central South University for financial support。
文摘The purpose of this paper is to review the current state of development of new composite materials for advanced aircraft engines. The advantages and disadvantages of Ti-base.NiAl-base, and MoSi_2-base composites as replacements for today's Ni-base superalloys are discussed from the standpoint of key technical issues. current status, and future directions. Results describing progress in both improved understanding of the mechanisms of deformation and fracture, and improved material performance will be covered.
基金the project supported by the Natural Science Foundation of Hubei Province(Grant No.2023BAB106)the National Natural Science Foundation of China(Grant No.U20A20239)the Scientific Research Project of Education Department of Hubei Province(D20211104).
文摘ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB_(2)-based ceramic samples were investigated.The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB_(2)-based ceramic composites and improve the physical properties of the materials.The flexural strength of the ceramic sample with 8 vol.%nano-graphite reached 418.54 MPa,which was 53.14% higher than that of ZrB_(2)-SiC ceramic material(273.31 MPa),and its oxidation resistance was also significantly improved.It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB_(2)-SiC ceramic composites.Via prolonging its service life in application and promoting the development of ZrB_(2)-based ceramic composites,it is of great significance for clean steel smelting.
基金supported by the Creative Research Foundation of the Science and Technology on Thermostructural Composite Materials Laboratory(No.2023-JCJQ-LB-071-01-01).
文摘The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,a tri-layered TGO scale,comprising cristobalite,Hf-doped SiO_(2)glass,and particle-reinforced Hf-Si-O glass,was formed during the oxidation of MoSi_(2)/HfO_(2)duplex EBCs.The incorporation of gradient Hf doping and HfO_(2)/HfSiO_(4)particle reinforcement effectively suppressed the crystallization and phase transition of SiO_(2)and mitigated the internal stress within the EBCs,generating a crack-blocking effect.This effect prevented the scale of the TGOs from further channel crack propagation,enabling the SiC substrate with no detectable corrosion after 200 h of exposure at 1500℃in steam,even when the TGOs thickness reached 24.5μm.This work presents a novel strategy to simultaneously extend the service lifetime and enhance the high-temperature capability of EBCs through the tailored design of TGO composition and structure.
基金supported by the China Postdoctoral Science Foundation (grant Nos.2019M662405,2019M650612)Natural Science Foundation of Shandong Province (grant Nos.ZR2019BF047,ZR2020KE059)+1 种基金School City Integration in Zibo (grant No.2019ZBXC299)Heilongjiang Touyan Team Program,and the Fundamental Research Funds for the Central Universities (grant No.HIT.0CEF.2021003).
文摘In recent years,significant progress has been achieved in the creation of innovative functional materials for energy storage and conversion.Due to their distinct physicochemical characteristics,ultrathin nanosheets composed of common layered transition metal sulfide materials(MoS2)have demonstrated promise as high-capacity anode materials for lithium-ion batteries(LIBs).Nevertheless,their practical application is severely limited by the tendency of monolayer nanosheets to restack due to strong van der Waals forces,dramatic volume changes during successive cycles,and low intrinsic conductivity.Recent research advances have shown that composite structures and nanowire morphologies with specific morphologies effectively overcome these issues.This paper reviews the recent research progress on molybdenum disulfide-based composites as anode materials for LIBs and discusses in detail the struc-tural characteristics of pure molybdenum disulfide and other composite forms of molybdenum disulfide.In addition,the phase engineering,defect engineering,and lithium storage mechanisms of molybdenum disulfide and the synthesis of molybdenum disulfide-based nanocomposites by different preparation methods are focused on.Finally,we review the design(structure),recent developments,and challenges of novel anode materials and consider their electrochemical performance in Li-ion batteries.
基金National Natural Science Foundation of China(No.61761047 and 41876055)the Yunnan Provincial Depart-ment of Science and Technology through the Key Project for the Science and Technology(Grant No.2017FA025)Program for hnovative Research Team(in Science and Technology)in University of Yunnan Province.
文摘Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecting different hazardous gases.TiO_(2) nanomaterials are promising candidates with great potential and excellent per-formance in gas sensor applications,such as hydrogen,acetone,ammonia,and ethanol detection.This review begins with a detailed discussion of the di ferent dimensional morphologies of TiO_(2),whitch affect the gas sensing performance of TiO_(2) sensors.The diverse morphologies of TiO_(2) can easily be tuned by regulating the manufacturing conditions.Meanwhile,they exhibit unique characteristics for detecting gases,including large specific suface area,superior elecron tr ansport rates,extraordinary pemmeability,and active reaction sites,which offer new opportunities to improve the gas sensing properties.In addition,a variety of efforts have been made to functional TiO_(2) nanomaterials to further enhance sensing properties,including TiO_(2)-based composites and light-assisted gas sensors.The enhanced gas sensing mechanisms of multi-component composite nano-materials based on TiO_(2) include loaded noble metals,doped elements,constructed heterojunctions,and com-pounded with other functional materials.Finally,several studies have been summarized to demonstate the compar ative sensing properties of TiO_(2)-based gas sensors.
基金National Science technology Support Plan Projects"(2012BAE06B00)
文摘TWC-equipped exhausts are widely used in gasoline-fueled vehicles to meet stringent emission regulations. The main components in TWCs are precious metals such as palladium (Pd), platinum (Pt), and rhodium (Rh) as the active component, and inorganic oxides such as γ-alumina (Al 2 O 3 ), ceria (CeO 2 ), zirconia (ZrO 2 ) and ceria-zirconia (CeO 2-ZrO 2 ) are used as the support. Interaction of precious metals and support plays an important role in the thermal stability and catalytic performance of TWCs. The support can improve the dispersion of precious metals and suppress the sintering of precious metals at high temperature. In the same, precious metals can also enhance the redox performance and oxygen storage capacity of support. This paper reviews the reaction phenomenon and mechanism of precious metals (Pt, Pd, Rh) and supports such as Al 2 O 3 , CeO 2-based composite oxides.
