Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are ve...Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are very susceptible to destructive oxidation and thus fail at elevated temperatures.Though matrix modification and coating technologies with Si-based and ultra-high temperature ceramics(UHTCs)are valid to enhance the oxidation/ablation resistance of C/Cs,it’s not sufficient to satisfy the increasing practical applications,due to the inherent brittleness of ceramics,mismatch issues between coatings and C/C substrates,and the fact that carbonaceous matrices are easily prone to high-temperature oxidation.To effectively solve the aforementioned problems,micro/nano multiscale reinforcing strategies have been developed for C/Cs and/or the coatings over the past two decades,to fabricate C/Cs with high strength and excellent high-temperature stability.This review is to systematically summarize the most recent major and important advancements in some micro/nano multiscale strategies,including nanoparticles,nanowires,carbon nanotubes/fibers,whiskers,graphene,ceramic fibers and hybrid micro/nano structures,for C/Cs and/or the coatings,to achieve high-temperature oxidation/ablation-resistant C/Cs.Finally,this review is concluded with an outlook of major unsolved problems,challenges to be met and future research advice for C/Cs with excellent comprehensive mechanical-thermal performance.It’s hoped that a better understanding of this review will be of high scientific and industrial interest,since it provides unusual and feasible new ideas to develop potential and practical C/Cs with improved high-temperature mechanical and oxidation/ablation-resistant properties.展开更多
Extensive attention has been drawn to the development of carbon fiber composites for their application in brake disks due to the increasing demand for brake disks with high mechanical strength and better tribological ...Extensive attention has been drawn to the development of carbon fiber composites for their application in brake disks due to the increasing demand for brake disks with high mechanical strength and better tribological properties.Herein,we design SiC hexagonal nanopyramids modified carbon/carbon(SiCNPsC/C)composites,in which SiCNPs are radially grafted on the carbon fibers by the combined sol-gel and carbothermal reduction method,and pyrolytic carbon(Py C)matrix is deposited on nucleation sites including carbon fibers and SiCNPs by isothermal chemical vapor infiltration(ICVI).Benefiting from the special structure,SiCNPs-C/C composites exhibit superior mechanical and frictional performance.Compared with C/C composites,SiCNPs-C/C composites have 147%,90.3%,70.6%,and 117.9%improvement in the hardness,interlaminar shear strength,and out-of-plane and in-plane compressive strength,respectively,which is attributed to the optimized fiber/matrix(F/M)interfaces bonding and the enhanced cohesion strength of Py C matrix.In addition,the friction coefficient of SiCNPs-C/C composites increases by 25.5%,and the wear rate decreases by 38.0%.This work provides an optional design thought for the nanomaterials and enlightens the mechanical and frictional modification of composites in the field of the brakes.展开更多
Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones suc...Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.展开更多
Extensive attention has been drawn to the development of carbon-matrix composites for application in the aerospace and military industry,where a combination of high mechanical strength and excellent frictional propert...Extensive attention has been drawn to the development of carbon-matrix composites for application in the aerospace and military industry,where a combination of high mechanical strength and excellent frictional properties are required.Herein,carbon-matrix composites reinforced by Si_(3)N_(4)nanowires@pyrolytic carbon nanolayers(Si_(3)N_(4nws)@PyCnls)coupled with hydroxyapatite nanosheets is reported.The Si_(3)N_(4nws)@PyCnls(SP)with coaxial structure could increase the surface roughness of Si_(3)N_(4nws)and promote the stress transfer to the carbon matrix,whereas the porous hydroxyapatite nanosheets favor the infiltration of the carbon matrix and promote the interfacial bonding between the SP and carbon matrix.The carbon matrix composites reinforced by SP coupled with hydroxyapatite nanosheets(Si_(3)N_(4nws)@PyCnls-HA-C)exhibit excellent mechanical strength.Compare with the conventional Si_(3)N_(4nws)reinforced carbon composites,Si_(3)N_(4nws)@PyCnls-HA-C(SPHC)have 162%and 249%improvement in flexural strength and elastic modulus,respectively.Moreover,the friction coefficient and wear rate decreased by 53%and 23%,respectively.This study provides a co-reinforcement strategy generated by SP coupled with hydroxyapatite nanosheets for effective improvement of mechanical and frictional properties of carbon matrix composites that are used for aerospace and military industry applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.91860203,51821091,51872239,52002321 and 52061135102)the China Postdoctoral Science Foundation(No.2019M660265)+3 种基金the Fundamental Research Funds for the Central Universities(China,Nos.G2019KY05116,G2020KY05125)the Innovation Talent Promotion Plan of Shaanxi Province for Science and Technology Innovation Team(No.2020TD003)the Creative Research Foundation of Science and Technology on Thermostructural Composite Materials Laboratory(Nos.614291102010517,5050200015 and 5150200033)the Shaanxi Provincial Education Department of China(No.2020JQ-170)。
文摘Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are very susceptible to destructive oxidation and thus fail at elevated temperatures.Though matrix modification and coating technologies with Si-based and ultra-high temperature ceramics(UHTCs)are valid to enhance the oxidation/ablation resistance of C/Cs,it’s not sufficient to satisfy the increasing practical applications,due to the inherent brittleness of ceramics,mismatch issues between coatings and C/C substrates,and the fact that carbonaceous matrices are easily prone to high-temperature oxidation.To effectively solve the aforementioned problems,micro/nano multiscale reinforcing strategies have been developed for C/Cs and/or the coatings over the past two decades,to fabricate C/Cs with high strength and excellent high-temperature stability.This review is to systematically summarize the most recent major and important advancements in some micro/nano multiscale strategies,including nanoparticles,nanowires,carbon nanotubes/fibers,whiskers,graphene,ceramic fibers and hybrid micro/nano structures,for C/Cs and/or the coatings,to achieve high-temperature oxidation/ablation-resistant C/Cs.Finally,this review is concluded with an outlook of major unsolved problems,challenges to be met and future research advice for C/Cs with excellent comprehensive mechanical-thermal performance.It’s hoped that a better understanding of this review will be of high scientific and industrial interest,since it provides unusual and feasible new ideas to develop potential and practical C/Cs with improved high-temperature mechanical and oxidation/ablation-resistant properties.
基金the National Natural Science Foundation of China(Nos.51872232,51972271,and 51872234)Natural Science Basic Research Plan in Shaanxi(No.2022JC-25)。
文摘Extensive attention has been drawn to the development of carbon fiber composites for their application in brake disks due to the increasing demand for brake disks with high mechanical strength and better tribological properties.Herein,we design SiC hexagonal nanopyramids modified carbon/carbon(SiCNPsC/C)composites,in which SiCNPs are radially grafted on the carbon fibers by the combined sol-gel and carbothermal reduction method,and pyrolytic carbon(Py C)matrix is deposited on nucleation sites including carbon fibers and SiCNPs by isothermal chemical vapor infiltration(ICVI).Benefiting from the special structure,SiCNPs-C/C composites exhibit superior mechanical and frictional performance.Compared with C/C composites,SiCNPs-C/C composites have 147%,90.3%,70.6%,and 117.9%improvement in the hardness,interlaminar shear strength,and out-of-plane and in-plane compressive strength,respectively,which is attributed to the optimized fiber/matrix(F/M)interfaces bonding and the enhanced cohesion strength of Py C matrix.In addition,the friction coefficient of SiCNPs-C/C composites increases by 25.5%,and the wear rate decreases by 38.0%.This work provides an optional design thought for the nanomaterials and enlightens the mechanical and frictional modification of composites in the field of the brakes.
基金supported by the Engineering and Physical Sciences Research Council(EPSRC)of the U.K.(Grant No.EP/P018998/1)the Acoustofluidics Special Interest Group of the UK Fluids Network(Grant No.EP/N032861/1)the EPSRC Centre for Doctoral Training in Renewable Energy Northeast Universities(ReNU)(Grant No.EP/S023836/1).
文摘Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.
基金his work was supported by the National Natural Science Foundation of China under Grant Nos.51872232the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(Grant No.136-QP-2015),the“111”project of China(B08040)+1 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates(Grand No.S202010699336)Project supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U21B2067).
文摘Extensive attention has been drawn to the development of carbon-matrix composites for application in the aerospace and military industry,where a combination of high mechanical strength and excellent frictional properties are required.Herein,carbon-matrix composites reinforced by Si_(3)N_(4)nanowires@pyrolytic carbon nanolayers(Si_(3)N_(4nws)@PyCnls)coupled with hydroxyapatite nanosheets is reported.The Si_(3)N_(4nws)@PyCnls(SP)with coaxial structure could increase the surface roughness of Si_(3)N_(4nws)and promote the stress transfer to the carbon matrix,whereas the porous hydroxyapatite nanosheets favor the infiltration of the carbon matrix and promote the interfacial bonding between the SP and carbon matrix.The carbon matrix composites reinforced by SP coupled with hydroxyapatite nanosheets(Si_(3)N_(4nws)@PyCnls-HA-C)exhibit excellent mechanical strength.Compare with the conventional Si_(3)N_(4nws)reinforced carbon composites,Si_(3)N_(4nws)@PyCnls-HA-C(SPHC)have 162%and 249%improvement in flexural strength and elastic modulus,respectively.Moreover,the friction coefficient and wear rate decreased by 53%and 23%,respectively.This study provides a co-reinforcement strategy generated by SP coupled with hydroxyapatite nanosheets for effective improvement of mechanical and frictional properties of carbon matrix composites that are used for aerospace and military industry applications.
