The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(...The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(3))was employed to modify laser-clad Fe45 alloy coatings,and the effects of Y_(2)O_(3) addition on their microstructure,microhardness,and tribological properties were investigated.As the Y_(2)O_(3) content increases from 0%to 0.3wt.%,the dominant microstructure transforms from columnar crystals to fine cellular and equiaxed crystals.The modified coating with 0.3wt.%Y_(2)O_(3) achieves a surface hardness of 568 HV_(0.3)and a wear volume of 1,735.41 um~3,representing a 14.06%increase in hardness and a 51.16%reduction in wear volume compared to the undoped coating.Further increasing the Y_(2)O_(3) content from 0.3wt.%to 0.9wt.%gradually leads to the emergence of a coarser feather-like microstructure,characterized by a dendritic framework with inter-dendritic equiaxed crystals.Concurrently,both the hardness and wear resistance of the coating decrease.Nevertheless,all Y_(2)O_(3)-modified coatings surpass the undoped Fe45 coating in both hardness and wear resistance.Appropriate Y_(2)O_(3) doping effectively refines the Fe45 alloy coating's microstru cture and induces lattice distortion,thereby enhancing its hardness and wear resistance.展开更多
The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their im...The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their impact and ensure human safety in modern society.Fe-based EWA materials have garnered significant attention owing to their cost-effectiveness,high saturation magnetization,and superior magnetic loss capabilities.This review begins with an introduction to Fe-based EWA materials,followed by a brief description of their EWA mechanisms.Various pristine Fe-based absorbers,such as carbonyl iron powder,ferrite-based materials,Fe-based alloys,Fe-based high-entropy alloys(HEAs),and Fe-based layered ternary transition-metal borides,have been systematically reviewed.Key strategies to enhance the performance of Fe-based composite absorbers,including doping,in-situ oxidation,porous structuring,and composite construction,are critically discussed.Finally,the review presents a summary and future perspectives in this field,highlighting the synergy between Fe-based and high-entropy materials in advancing next-generation EWA for applications in stealth technology,wear-able electronics,and harsh environments.展开更多
Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that ...Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.展开更多
The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fab...The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.展开更多
基金supported by the Jiangxi Provincial Natural Science Foundation of China(Grant number 20224BAB204049)the Fund Project of Jiangxi Provincial Department of Education(Grant number GJJ2200602)the National Natural Science Foundation of China(Grant number 52205194)。
文摘The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(3))was employed to modify laser-clad Fe45 alloy coatings,and the effects of Y_(2)O_(3) addition on their microstructure,microhardness,and tribological properties were investigated.As the Y_(2)O_(3) content increases from 0%to 0.3wt.%,the dominant microstructure transforms from columnar crystals to fine cellular and equiaxed crystals.The modified coating with 0.3wt.%Y_(2)O_(3) achieves a surface hardness of 568 HV_(0.3)and a wear volume of 1,735.41 um~3,representing a 14.06%increase in hardness and a 51.16%reduction in wear volume compared to the undoped coating.Further increasing the Y_(2)O_(3) content from 0.3wt.%to 0.9wt.%gradually leads to the emergence of a coarser feather-like microstructure,characterized by a dendritic framework with inter-dendritic equiaxed crystals.Concurrently,both the hardness and wear resistance of the coating decrease.Nevertheless,all Y_(2)O_(3)-modified coatings surpass the undoped Fe45 coating in both hardness and wear resistance.Appropriate Y_(2)O_(3) doping effectively refines the Fe45 alloy coating's microstru cture and induces lattice distortion,thereby enhancing its hardness and wear resistance.
基金support from the National Natural Science Foundation of China (Nos.52377026 and52301192)Taishan Scholars and Young Experts Program of Shandong Province,China (No.tsqn202103057)+2 种基金Natural Science Foundation of Shandong Province,China (Nos.ZR2024ME046 and ZR2024QE313)Natural Science Basic Research Program of Shaanxi,China (No.2025JC-YBMS-396)Postdoctoral Science Foundation of China (No.2024M761554)
文摘The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their impact and ensure human safety in modern society.Fe-based EWA materials have garnered significant attention owing to their cost-effectiveness,high saturation magnetization,and superior magnetic loss capabilities.This review begins with an introduction to Fe-based EWA materials,followed by a brief description of their EWA mechanisms.Various pristine Fe-based absorbers,such as carbonyl iron powder,ferrite-based materials,Fe-based alloys,Fe-based high-entropy alloys(HEAs),and Fe-based layered ternary transition-metal borides,have been systematically reviewed.Key strategies to enhance the performance of Fe-based composite absorbers,including doping,in-situ oxidation,porous structuring,and composite construction,are critically discussed.Finally,the review presents a summary and future perspectives in this field,highlighting the synergy between Fe-based and high-entropy materials in advancing next-generation EWA for applications in stealth technology,wear-able electronics,and harsh environments.
基金financially supported by Natural Science Foundation of Shandong Province(Grant No.ZR2021ME019).
文摘Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.
基金support from the National Key Research and Development Program of China(2022YFB4600101)the National Natural Science Foundation of China(52505231 and 52175201)+5 种基金the Key R&D Program of Shandong Province(2024CXPT035)the Research Program of Science and Technology Department of Gansu Province(24JRRA059,24JRRA044 and 24ZDGA014)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(AMGM2024F12)the Innovation and Entrepreneurship Team Prject of YEDA(2021TD007)the Special Supporting Project for Provincial Leading Talents of Yantai,the Major Program(ZYFZFX-2)the Fundamental Research Special Zone Project of the Lanzhou Institute of Chemical Physics,CAS,the Special Research Assistant Project of the Chinese Academy of Sciences,and the Taishan Scholars Program.
文摘The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.
