Aero-engine is a key part of aircraft,the operating temperature of which is being pushed to unprecedented levels for higher engine efficiency and performance.To accomplish higher gas-inlet temperature of aero-engines,...Aero-engine is a key part of aircraft,the operating temperature of which is being pushed to unprecedented levels for higher engine efficiency and performance.To accomplish higher gas-inlet temperature of aero-engines,applying thermal barrier coatings(TBCs)on hot-section metallic components,or even replacing some of the metallic components in aero-engines with ceramic-matrix composites(CMCs)and applying environmental-barrier coatings(EBCs)on them,are effective methods and have been widely accepted.On the other hand,increasing aero-engines operating temperature causes the aircraft more easily be detected,thus stealth coatings are necessary for engines.Except the hottest part in aero-engines,other parts may not need TBCs or EBCs due to the relatively low operating temperature,but they still need protection from oxidation and corrosion.Hence,corrosion-resistant coatings are essential.In this paper,the latest progress of the above high-temperature protective coatings,i.e.,TBCs,EBCs,stealth coatings and corrosion-resistant coatings is reviewed,mainly including their materials,fabrication technologies and performance.In addition,due to the harsh operating environment,these protective coatings face many threats such as calcia-magnesia-aluminosilicates(CMAS)attack,causing premature failure of the coatings,which is also concerned in this paper.The work would provide a comprehensive understanding on the high-temperature protective coatings in aero-engines and guidance for developing advanced protective coatings for next-generation aero-engines.展开更多
SiC particle reinforced Al matrix composites(SiC_(p)/Al MMCs)have been widely used in aerospace and other fields due to their excellent mechanical properties,and their machined surface integrity is crucial for the use...SiC particle reinforced Al matrix composites(SiC_(p)/Al MMCs)have been widely used in aerospace and other fields due to their excellent mechanical properties,and their machined surface integrity is crucial for the use of new generation high-tech equipment.In order to enhance the understanding and regulation of machined surface integrity in Al matrix composites,this article provides a comprehensive review of the research advancements regarding influential factors,damage characteristics,creation techniques for machined surfaces,as well as technologies for controlling machined surface integrity both domestically and internationally.The present study discusses the key issues and solutions in the processing of aluminum matrix composite materials,along with examining the extent and mechanism of various energy field assistance influence on the surface integrity of mechanically processed aluminum matrix composites.Ultimately,this article proposes future research prospects for achieving high surface integrity machining of aluminum matrix composites.展开更多
Siloxane coatings,characterized by their low surface energy and low elastic modulus,exhibit promising foulingrelease properties.However,siloxane antifouling coatings still have certain limitations,which include low ad...Siloxane coatings,characterized by their low surface energy and low elastic modulus,exhibit promising foulingrelease properties.However,siloxane antifouling coatings still have certain limitations,which include low adhesion strength,poor antifouling performance,and weak mechanical properties.This review summarizes the modification methods of siloxane coatings,and focuses on three modification strategies:improving coating adhesion,static antifouling performance,and self-healing capabilities.This review provides insight into the preparation methods,enhancement mechanism and key critical issues of the three strategies.Additionally,potential research methods and materials that can further augment siloxane coating performance in the future were evaluated.Computational techniques such as molecular dynamics can aid researchers in understanding structural modification strategies at the molecular level.Photocatalytic antifouling agents are more suitable for future scientific and environmentally friendly design concepts.It is hope that this contribution provides valuable insights for researchers seeking a better understanding of advancements in siloxane antifouling coatings research and aids in developing novel solutions to address marine fouling issues.展开更多
In recent years,there has been a growing interest and research focus on infrared optical thin films as essential components in infrared optical systems.In practical applications,extreme environmental factors such as a...In recent years,there has been a growing interest and research focus on infrared optical thin films as essential components in infrared optical systems.In practical applications,extreme environmental factors such as aerodynamic heating and mechanical stresses,electromagnetic interferences,laser interferences,sand erosions,and rain erosions all lead to issues including cracking,wrinkling,and delaminations of infrared thin films.Extreme application environment imposes stringent requirements on functional films,necessitating high surface hardness,stability,and adhesion.Additionally,for multispectral optical transmissions,infrared optical thin films are expected to exhibit high transmittance in the visible and far-infrared wavelength bands while possessing tunability and optical anti-reflection properties in specific wavelength ranges.Electromagnetic shielding requires superior electrical performance,while resisting laser interference demands rapid phase change capabilities.This paper focuses on current research progresses in infrared optical thin films under extreme conditions such as opto,electro,thermos and mechanical environments.Table of Contents Graphic gives detailed outline.Future opportunities and challenges are also highlighted.展开更多
Ammonia is a premium energy carrier with high content of hydrogen.However,energy storage and utilization via ammonia still confront multiple challenges.Here,we review recent progress and discuss challenges for the key...Ammonia is a premium energy carrier with high content of hydrogen.However,energy storage and utilization via ammonia still confront multiple challenges.Here,we review recent progress and discuss challenges for the key steps of energy storage and utilization via ammonia(including hydrogen production,ammonia synthesis and ammonia utilization).In hydrogen production,we focus on important processes and catalytic designs for conversion of carbon feedstocks and water into hydrogen.To reveal crucial challenges of ammonia synthesis,catalytic designs and mechanisms are summarized and analyzed,in thermocatalytic synthesis,electrocatalytic synthesis and photocatalytic synthesis of ammonia.Further,in ammonia utilization,important processes and catalytic designs are outlined for ammonia decomposition,ammonia fuel cells and ammonia combustion.The goal of this review is to stimulate development of low-cost and eco-friendly ways for energy storage and utilization via ammonia.展开更多
Superlubricity is an ideal state with zero contact friction between two frictional interfaces.It has become a hot research topic for many scientists in the past 20 years,and the field spans the complex hot research di...Superlubricity is an ideal state with zero contact friction between two frictional interfaces.It has become a hot research topic for many scientists in the past 20 years,and the field spans the complex hot research directions of physics,chemistry,mechanics,and materials.The concept of superlubricity was introduced in 1990,and the understanding of the process of realizing superlubricity is vital for controlling the tribological properties of materials and promoting the development of tribology.This review focuses on the fundamental properties of molybdenum disulfide(MoS_(2))films and the influence of the environment on affecting MoS_(2) films.As a result,some methods for realizing superlubricity by MoS_(2) films are proposed.The key to achieving superlubricity with MoS_(2) is summarized.Finally,an outlook on the application of MoS_(2) films is given.展开更多
Thermal control coating is necessary for the B_(4)C/Al matrix composites(AMCs)used in nuclear power field.Microarc Oxidation(MAO)technology is a suitable method to prepare thermal control coating on B_(4)C/AMCs,but th...Thermal control coating is necessary for the B_(4)C/Al matrix composites(AMCs)used in nuclear power field.Microarc Oxidation(MAO)technology is a suitable method to prepare thermal control coating on B_(4)C/AMCs,but the B_(4)C reinforcements has a great influence on the MAO process.In this paper,the effects of the B_(4)C content on the spark discharge,microstructure and properties of the MAO films were studied by a Dual-channel Oscilloscope,Scanning Electron Microscopy(SEM)and Electrochemical Impedance Spectroscopy(EIS).The results indicate that the spark discharge in the early stage of oxidation is inhibited with the increase of the B_(4)C particles in AMCs,but the effect declines in the later stage.Also,the compactness and blackness of the MAO films reduce due to the negative effect of the B_(4)C particles on the oxidation process,but the lowest emissivity of the MAO film is still higher than 0.85,which can still meet the general requirement for thermal control coatings in actual applications.展开更多
With the development of technology in aerospace,medical devices and other fields,high-performance difficult-tomachine materials have been widely used in these fields due to their good comprehensive mechanical properti...With the development of technology in aerospace,medical devices and other fields,high-performance difficult-tomachine materials have been widely used in these fields due to their good comprehensive mechanical properties.However,when using traditional machining methods,it is difficult to ensure the machining accuracy and surface quality,and at the same time,there are problems such as serious tool wear and low machining efficiency.Laserassisted machining(LAM)technology is an advanced manufacturing process that softens the material in the machining area through the preheating effect of the laser,thus reducing the surface hardness of the material and improving the machinability of the material,which has the advantages of high efficiency and economy in machining difficult-tomachine materials.This paper introduces the common methods of establishing thermal models and simulation modeling of removal behavior in the LAM material removal process,summarizes the research progress on the removal behavior of LAM processing of various difficult-to-machine materials,and analyzes the shortcomings and challenges of the current research.Finally,the key issues of LAM material removal mechanism are proposed,and the development direction of LAM material removal technology is envisioned in order to provide a reference for the research and development in this field.展开更多
Braking discs play an important role for the safety of vehicles whereas severe frictional contacts in repeated braking operations result in thermal and tribological failures.This paper reports comprehensive surface an...Braking discs play an important role for the safety of vehicles whereas severe frictional contacts in repeated braking operations result in thermal and tribological failures.This paper reports comprehensive surface and subsurface analyses of a used grey cast iron braking disc to investigate its failure mechanisms as well as related microstructure evolution.Thermal cracking,spalling wear and tribo-oxidation have been found to contribute to the wear failure.The flake-type graphite of the grey cast iron triggered propagation and internal oxidation of the metallic matrix.In a depth of 3 mm beneath the rubbing surface,extensive microstructure evolution occurred by severe plastic deformation of the ferritic matrix,nodularisation and partial dissolution of the lamellar carbides,and internal oxidation.The microstructure evolution resulted in decreased surface hardness to HV0.3247 as compared to HV0.3284 of the bulk cast iron.展开更多
Titanium alloys have been extensively applied due to their outstanding features,including high specific strength and corrosion resistance.However,the machining of these alloys presents challenges,leading to significan...Titanium alloys have been extensively applied due to their outstanding features,including high specific strength and corrosion resistance.However,the machining of these alloys presents challenges,leading to significant tool wear and reduced tool lifetime,ascribed to the difficult-to-machine features of Ti alloys.In the context of pursuing environmental sustainability and enhanced productivity,high-speed dry-cutting technology coupled with high-quality tool coatings are prospective.This paper comprehensively explores wear patterns and recent advancements in tool coatings for high-speed dry cutting of Ti-alloys.Key coating properties such as resistance to abrasion,adhesion,oxidation,fatigue,hot hardness,and self-adaptability are briefly introduced.Design strategies for enhancing micro-hardness,toughness,and adhesion,including nanocomposite,multilayer,and gradient architectures,are also discussed.Furthermore,the paper highlights several Boron(B)doped hard coatings as promising candidates for high-speed dry cutting against Ti-alloys,exploring the impact of B on microstructure,hardness,thermal stability,oxidation resistance,and lubrication.In summary,this work provides a systematic overview of novel B-doped tool coatings applied in highspeed dry cutting against Ti-alloys.展开更多
The work combined scanning Kelvin probe force microscopy measurements and finite element modelling to study the diffusion and distribution of hydrogen(H)atoms at metallurgical microphases contained in X52 pipeline ste...The work combined scanning Kelvin probe force microscopy measurements and finite element modelling to study the diffusion and distribution of hydrogen(H)atoms at metallurgical microphases contained in X52 pipeline steel.Results show that the pearlite contained in the steel is more stable than the ferrite during electropolishing,as indicated by the measured topographic profiles and Volta potentials.The hydrogen(H)-charging enhances the electrochemical activity of both pearlite and ferrite,as shown by increased Volta potential and thus the decreased work function.As the H-charging time increases,the Volta potentials of both phases further increase,implying that their activities increase with the H-charging time.The pearlite has a greater Volta potential and thus a lower work function than the ferrite.This is associated with more H atoms accumulating at the pearlite than at the ferrite.The H atom diffusion and accumulation are affected by H diffusivity at phase boundaries,H-trap binding energy and the number of traps in the steel.展开更多
In this work,investigations were conducted into the adsorption behaviour and inhibitory effect of Mukia maderaspatana leaves extract on the corrosion of mild steel in 1.5M HCl solution at several temperatures.The tech...In this work,investigations were conducted into the adsorption behaviour and inhibitory effect of Mukia maderaspatana leaves extract on the corrosion of mild steel in 1.5M HCl solution at several temperatures.The techniques included chemical methods(weight loss measurements),surface analysis(SEM,FESEM)and solution analysis(UV–visible spectrophotometric,ICP-MS)techniques.The examination of the data revealed that the efficiency of inhibition rose as the inhibitor’s concentration increased and fell as the temperature increased.At 30 degrees Celsius,the concentration of inhibitor resulted in an increase in corrosion inhibition efficiency,reaching 99.02%efficiency at 8%concentration.The physical adsorption of the inhibitor on the metal surface was demonstrated by the adsorption free energy of the plant extract on mild steel.The conclusions above are supported by data from examinations of Scanning Electron Microscopy,FESEM,UV–visible and Fourier transform infrared spectrophotometry.展开更多
Sericin is a highly hydrophilic macromolecular protein comprising 18 amino acids.It is considered biocompatible,nontoxic,and has antibacterial and antioxidant properties.It is applied on fabric,however,either the fabr...Sericin is a highly hydrophilic macromolecular protein comprising 18 amino acids.It is considered biocompatible,nontoxic,and has antibacterial and antioxidant properties.It is applied on fabric,however,either the fabric needs to be pretreated with electrolytes or catalyst are used thereby increasing the number of processing steps.This study achieved sericin with multifunctional properties through chemical modification using cyanuric chloride.Modified sericin was applied in the dyeing stage along with the dyes on various textile substrates like wool,silk,and polyester.The functional properties were characterized by Fourier transform infrared and in modified sericin new chlorine peak at 779 cm−1 was obtained,X-ray diffractogram shows increase in crystallinity after modification of sericin,SEM showed particles of sericin on all fabrics even after 5 washes.Fabrics were analysed for antimicrobial activity and showed antimicrobial properties against gram negative and positive bacteria.Fastness properties and ultra violet protection factor of the samples were also determined.展开更多
In recent years,the requirements for high-quality development in the manufacturing industry and extreme application conditions have increasingly demanded higher equipment performance.The surface and interface conditio...In recent years,the requirements for high-quality development in the manufacturing industry and extreme application conditions have increasingly demanded higher equipment performance.The surface and interface condition of components is directly related to the stability,reliability and service life of equipment.The development of high-performance or multi-performance surface texturing is of great significance for the effective improvement of mechanical properties,optical properties,catalytic properties and biological properties of surfaces.This paper summarizes the application of textured surfaces in improving the physical,chemical and biological properties of surfaces;outlines the types of texturing patterns and the design methods;analyzes the main technical methods and their characteristics for the preparation of surface textures in additive manufacturing,subtractive manufacturing and equal material manufacturing;and makes outlooks on texturing surfaces from the aspects of performance enhancement,pattern design and manufacturing technology in combination with the development trend of textured surfaces’intelligence and digitization.展开更多
This paper introduces the definition,classification,and running modes of fretting damage,as well as industrial phenomena of fretting damage cases.It is detail reviewed the progress of two-types fretting map theory(run...This paper introduces the definition,classification,and running modes of fretting damage,as well as industrial phenomena of fretting damage cases.It is detail reviewed the progress of two-types fretting map theory(running condition fretting map-RCFM and material response fretting map-MRFM),and outlines the protection strategy of fretting wear according to the fretting map theory,i.e.eliminating the mixed fretting regime and slip regime,increasing the strength of the contact surface,reducing the coefficient of friction,and selecting and matching of materials.Several surface engineering techniques(such as PVD,laser surface modification technology,bonded solid lubricant coating,thermal spraying coating,and micro-arc oxidation coating)against fretting wear are reviewed,several mechanisms to alleviating fretting wear are proposed as well as a collection of practical examples of surface engineering designs to anti-fretting wear.Base on the review of previous studies,mechanisms of surface engineering technologies for alleviating fretting wear have been proposed.In addition,the content and process of surface engineering design are introduced in this paper.A quantitative evaluation method using polar coordinate diagram is applied to choose appropriate surface engineering technology.Finally,taking the locking pin of variable gauge train as an example,the process of surface engineering design is further expounded.展开更多
Catalytic CO_(2) hydrogenation to valuable chemicals is an excellent approach to address the increasingly serious“greenhouse effect”caused by CO_(2) emission generated from the utilizations of nonrenewable fossil en...Catalytic CO_(2) hydrogenation to valuable chemicals is an excellent approach to address the increasingly serious“greenhouse effect”caused by CO_(2) emission generated from the utilizations of nonrenewable fossil energies,while such a process is limited by chemical inertia and thermal stability of the CO_(2) molecule and complex hydrogenation routes.In this review,we first summarized the recent progresses of metal-oxide nanocatalysts considered as a category of the most promising catalysts in CO_(2) hydrogenation to value-added C1 chemicals including CH_(4)/CO,formic acid/formate,and methanol.These studies involve with different structural factors affecting the metal-oxide interfacial catalysis including the structures of both the metals(type,particle size,morphology/crystal plane,and bimetal alloy)and the supports(type,particle size,crystal phase,morphology/crystal plane,and composite)and their(strong)metal-support interactions so as to identify the key factor determining the reaction activity,product selectivity,and catalytic stability in CO_(2) hydrogenation.Finally,we further discuss challenging coupling with future research opportunities for tunable interfacial catalysis of metal-oxide nanocatalysts in CO_(2) conversion.展开更多
Icing as a regular natural phenomenon in life poses a serious threat to human production and life,traditional mechanical deicing,chemical deicing,and other methods have the shortcomings of high pollution,high energy c...Icing as a regular natural phenomenon in life poses a serious threat to human production and life,traditional mechanical deicing,chemical deicing,and other methods have the shortcomings of high pollution,high energy consumption,and low efficiency,which limits their applicability and effectiveness of the scene of the above methods.With the expansion of global economic activities in recent years,the solution to the icing problem has become imminent.As a result,researchers have gradually deepened their studies related to anti-icing.Inspired by the lotus leaf effect,hogwash,polar,marine shellfish,and other natural organisms,anti-icing/deicing coatings can be designed functional biomimetic through both surface micro-nano structures and the physicochemical properties of the material.Superhydrophobic design is based on Young’s wetting equations,Wenzel’s wetting equations,and the Cassie-Baxter model of the superhydrophobic behavior of the interface formed by the liquid droplets and the surface,which prevents the droplets from spreading out and penetration to form heat exchange.The physicochemical properties are based on the slow-release behavior of chemical mediators inside the coating with properties such as super-lubrication and anti-freezing,which reduce the residence time and nucleation temperature of droplets on the surface.The coating effectively blocks the occurrence of icing behavior by passive means such as ultra-low interfacial wetting,interfacial slip,and lowering the freezing point of droplets,which has become a hot research direction.Meanwhile,the active anti-icing of photo-thermal,electro-thermal,phase change and other effects with the passive anti-icing to play a synergistic and complementary role for further enhance the anti-icing effect of the coating.To clarity the design mechanism and preparation process of the anti-icing/ice-removing surfaces,the article firstly classifies and introduces the coatings functioned according to the different mechanisms of action,and sums up the biomimetic super-hydrophobic design,the sacrificial type physicochemical characteristic.The article firstly classifies and introduces the functional types of coatings according to different mechanisms of action,and the latest research progress on the mechanism design of anti-icing coatings and their performance modification such as bionic superhydrophobic design,sacrificial physicochemical property design,microregion modulus control design and multifactorial coupling design were summarized.The problems of single-functionality and imbalance of performance of the existing coating mechanism design were analyzed and discussed,the view of the development trend and outlook of the development and application of icephobic coatings were put forward.展开更多
Plasma spraying-physical vapor deposition(PS-PVD)and atmospheric plasma spraying(APS),as new thermal spraying process,could prepare advanced thermal barrier coatings by successive scanning deposition layer by layer.To...Plasma spraying-physical vapor deposition(PS-PVD)and atmospheric plasma spraying(APS),as new thermal spraying process,could prepare advanced thermal barrier coatings by successive scanning deposition layer by layer.To investigate the layer structure of the coating,the transient in-situ deposit surface temperature was investigated by varying the scanning methods.Results show that,compared to unidirectional scanning method,alternating scanning method results in doubling heating duration,higher in-situ deposit temperature rising and thereby thicker well-bonded layer structure during each spray cycle for the coating deposited at the edge position of the scanning path.The erosion resistance of the coatings deposited by unidirectional scanning method is independent on deposition positions including edge position and center position.However,the erosion resistance of the coatings deposited at edge position by alternating scanning method is one time higher than those deposited by unidirectional scanning method.Finally,the erosion mechanism of layer spallation is revealed to explain the difference between different scanning methods.展开更多
The main issue with using biomass fuels in power plants is fireside corrosion.Applying corrosion-resistant coatings is one potential choice.The current study examines how a Ni-Al diffusion coating on austenitic stainl...The main issue with using biomass fuels in power plants is fireside corrosion.Applying corrosion-resistant coatings is one potential choice.The current study examines how a Ni-Al diffusion coating on austenitic stainless steel reacts to corrosion and interdiffusion(TP347H).Nickel was electrolytically deposited to create Ni-Al coatings,which were then pack aluminized at 650℃.With an internal layer of Ni and a Ni2Al3 outer layer,a homogenous and dense Ni-Al coating was created.Samples were heated to 560℃ for 168 h in an environment designed to simulate the combustion of biomass.A localized corrosion attack was the result.By using isothermal heat treatment in static air at 650℃ or 700℃ for up to 3000 h,interdiffusion was examined.In the course of the interdiffusion process,the Ni2Al3 eventually changed into NiAl and Ni3Al.At both temperatures,porosity formed at the intersection of the Ni-Al coating and the Ni layer and grew with time.展开更多
Grinding is a generally utilized method,removing excess materials through effective abrasives.The grinding abrasives with multiple shape-position characteristics play a dominant role in determining the thermo-mechanic...Grinding is a generally utilized method,removing excess materials through effective abrasives.The grinding abrasives with multiple shape-position characteristics play a dominant role in determining the thermo-mechanical coupling,which may influence the surface quality directly.To investigate this correlated influence mechanism,this paper focuses on the abrasive shape and position characteristic on the grinding thermo-mechanical process with the analytic single abrasive interaction force model by considering the abrasive shape and its distribution information.It can be found that the mapped dynamic grinding temperature is actually discretized on the workpiece surface,which is on account of the diversity of the abrasive shape and its distribution.Moreover,higher spherical and conical abrasive particles,as well as lower pyramid shaped abrasive particle ratios,can generate greater specific grinding energy with a discretized temperature distribution,when compared with a higher proportion of pyramid shaped abrasive.The study can be utilized to provide valuable theoretical foundation for engineering practice by preparing structural wheel and its grinding property.展开更多
文摘Aero-engine is a key part of aircraft,the operating temperature of which is being pushed to unprecedented levels for higher engine efficiency and performance.To accomplish higher gas-inlet temperature of aero-engines,applying thermal barrier coatings(TBCs)on hot-section metallic components,or even replacing some of the metallic components in aero-engines with ceramic-matrix composites(CMCs)and applying environmental-barrier coatings(EBCs)on them,are effective methods and have been widely accepted.On the other hand,increasing aero-engines operating temperature causes the aircraft more easily be detected,thus stealth coatings are necessary for engines.Except the hottest part in aero-engines,other parts may not need TBCs or EBCs due to the relatively low operating temperature,but they still need protection from oxidation and corrosion.Hence,corrosion-resistant coatings are essential.In this paper,the latest progress of the above high-temperature protective coatings,i.e.,TBCs,EBCs,stealth coatings and corrosion-resistant coatings is reviewed,mainly including their materials,fabrication technologies and performance.In addition,due to the harsh operating environment,these protective coatings face many threats such as calcia-magnesia-aluminosilicates(CMAS)attack,causing premature failure of the coatings,which is also concerned in this paper.The work would provide a comprehensive understanding on the high-temperature protective coatings in aero-engines and guidance for developing advanced protective coatings for next-generation aero-engines.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-IV-002-001 and P2023-B-IV-003-001)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the National Key Laboratory of Science and Technology on Helicopter Transmission(Nanjing University of Aeronautics and Astronautics)(No.HTL-A-22G12).
文摘SiC particle reinforced Al matrix composites(SiC_(p)/Al MMCs)have been widely used in aerospace and other fields due to their excellent mechanical properties,and their machined surface integrity is crucial for the use of new generation high-tech equipment.In order to enhance the understanding and regulation of machined surface integrity in Al matrix composites,this article provides a comprehensive review of the research advancements regarding influential factors,damage characteristics,creation techniques for machined surfaces,as well as technologies for controlling machined surface integrity both domestically and internationally.The present study discusses the key issues and solutions in the processing of aluminum matrix composite materials,along with examining the extent and mechanism of various energy field assistance influence on the surface integrity of mechanically processed aluminum matrix composites.Ultimately,this article proposes future research prospects for achieving high surface integrity machining of aluminum matrix composites.
基金supported by the National Natural Science Foundation of China(No.52371081,U2106226)the Key Technology Research and Development Program of Shandong Province(No.2020CXGC010703)the Foundation of Key Laboratory of National Defense Science and Technology(No.JS220406).
文摘Siloxane coatings,characterized by their low surface energy and low elastic modulus,exhibit promising foulingrelease properties.However,siloxane antifouling coatings still have certain limitations,which include low adhesion strength,poor antifouling performance,and weak mechanical properties.This review summarizes the modification methods of siloxane coatings,and focuses on three modification strategies:improving coating adhesion,static antifouling performance,and self-healing capabilities.This review provides insight into the preparation methods,enhancement mechanism and key critical issues of the three strategies.Additionally,potential research methods and materials that can further augment siloxane coating performance in the future were evaluated.Computational techniques such as molecular dynamics can aid researchers in understanding structural modification strategies at the molecular level.Photocatalytic antifouling agents are more suitable for future scientific and environmentally friendly design concepts.It is hope that this contribution provides valuable insights for researchers seeking a better understanding of advancements in siloxane antifouling coatings research and aids in developing novel solutions to address marine fouling issues.
基金funded by the following grants:the National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.51625201)the Key Project of National Natural Science Foundation of China(Grant No.52032004).
文摘In recent years,there has been a growing interest and research focus on infrared optical thin films as essential components in infrared optical systems.In practical applications,extreme environmental factors such as aerodynamic heating and mechanical stresses,electromagnetic interferences,laser interferences,sand erosions,and rain erosions all lead to issues including cracking,wrinkling,and delaminations of infrared thin films.Extreme application environment imposes stringent requirements on functional films,necessitating high surface hardness,stability,and adhesion.Additionally,for multispectral optical transmissions,infrared optical thin films are expected to exhibit high transmittance in the visible and far-infrared wavelength bands while possessing tunability and optical anti-reflection properties in specific wavelength ranges.Electromagnetic shielding requires superior electrical performance,while resisting laser interference demands rapid phase change capabilities.This paper focuses on current research progresses in infrared optical thin films under extreme conditions such as opto,electro,thermos and mechanical environments.Table of Contents Graphic gives detailed outline.Future opportunities and challenges are also highlighted.
基金supported by the National Natural Science Foundation of China(Nos.22221005,22278078,22178058 and 22108037)National Key R&D Program of China(Nos.2022YFB4002602 and 2022YFB4003701).
文摘Ammonia is a premium energy carrier with high content of hydrogen.However,energy storage and utilization via ammonia still confront multiple challenges.Here,we review recent progress and discuss challenges for the key steps of energy storage and utilization via ammonia(including hydrogen production,ammonia synthesis and ammonia utilization).In hydrogen production,we focus on important processes and catalytic designs for conversion of carbon feedstocks and water into hydrogen.To reveal crucial challenges of ammonia synthesis,catalytic designs and mechanisms are summarized and analyzed,in thermocatalytic synthesis,electrocatalytic synthesis and photocatalytic synthesis of ammonia.Further,in ammonia utilization,important processes and catalytic designs are outlined for ammonia decomposition,ammonia fuel cells and ammonia combustion.The goal of this review is to stimulate development of low-cost and eco-friendly ways for energy storage and utilization via ammonia.
基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 0470202)Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.Y202084)+2 种基金Key Program of the Lanzhou Institute of Chemical Physics,CAS(Grant No.KJZLZD-3 and ZYFZFX-4)Key Science and Technology Program of Gansu Province(Grant No.22ZD6GA002)National Natural Science Foundation of China(Grant No.52275222).
文摘Superlubricity is an ideal state with zero contact friction between two frictional interfaces.It has become a hot research topic for many scientists in the past 20 years,and the field spans the complex hot research directions of physics,chemistry,mechanics,and materials.The concept of superlubricity was introduced in 1990,and the understanding of the process of realizing superlubricity is vital for controlling the tribological properties of materials and promoting the development of tribology.This review focuses on the fundamental properties of molybdenum disulfide(MoS_(2))films and the influence of the environment on affecting MoS_(2) films.As a result,some methods for realizing superlubricity by MoS_(2) films are proposed.The key to achieving superlubricity with MoS_(2) is summarized.Finally,an outlook on the application of MoS_(2) films is given.
基金supported by the Guangxi Science and Technology Major Program(No.AA23023029 and NO.AA23023031).
文摘Thermal control coating is necessary for the B_(4)C/Al matrix composites(AMCs)used in nuclear power field.Microarc Oxidation(MAO)technology is a suitable method to prepare thermal control coating on B_(4)C/AMCs,but the B_(4)C reinforcements has a great influence on the MAO process.In this paper,the effects of the B_(4)C content on the spark discharge,microstructure and properties of the MAO films were studied by a Dual-channel Oscilloscope,Scanning Electron Microscopy(SEM)and Electrochemical Impedance Spectroscopy(EIS).The results indicate that the spark discharge in the early stage of oxidation is inhibited with the increase of the B_(4)C particles in AMCs,but the effect declines in the later stage.Also,the compactness and blackness of the MAO films reduce due to the negative effect of the B_(4)C particles on the oxidation process,but the lowest emissivity of the MAO film is still higher than 0.85,which can still meet the general requirement for thermal control coatings in actual applications.
基金supported by the National Natural Science Foundation of China(No.52175377)the Natural Science Foundation of Chongqing(No.CSTB2022NSCO-LZX0080)+2 种基金the Innovation Group Science Fund of Chongqing Natural Science Foundation(No.stc2019jcyj-cxttX0003)the Basic Research Funds for Central Universities(No.2023CDJXY-026 and No.2023CDJXY-021)Funded by Open Fund of State Key Laboratory of Mechanical Transmission,China(SKLMT-MSKFKT-202215).
文摘With the development of technology in aerospace,medical devices and other fields,high-performance difficult-tomachine materials have been widely used in these fields due to their good comprehensive mechanical properties.However,when using traditional machining methods,it is difficult to ensure the machining accuracy and surface quality,and at the same time,there are problems such as serious tool wear and low machining efficiency.Laserassisted machining(LAM)technology is an advanced manufacturing process that softens the material in the machining area through the preheating effect of the laser,thus reducing the surface hardness of the material and improving the machinability of the material,which has the advantages of high efficiency and economy in machining difficult-tomachine materials.This paper introduces the common methods of establishing thermal models and simulation modeling of removal behavior in the LAM material removal process,summarizes the research progress on the removal behavior of LAM processing of various difficult-to-machine materials,and analyzes the shortcomings and challenges of the current research.Finally,the key issues of LAM material removal mechanism are proposed,and the development direction of LAM material removal technology is envisioned in order to provide a reference for the research and development in this field.
基金partially funded by in the European Regional Development Fund of European Union in the title‘Sheffield Innovation Programme’with the series number 28R18P02582.
文摘Braking discs play an important role for the safety of vehicles whereas severe frictional contacts in repeated braking operations result in thermal and tribological failures.This paper reports comprehensive surface and subsurface analyses of a used grey cast iron braking disc to investigate its failure mechanisms as well as related microstructure evolution.Thermal cracking,spalling wear and tribo-oxidation have been found to contribute to the wear failure.The flake-type graphite of the grey cast iron triggered propagation and internal oxidation of the metallic matrix.In a depth of 3 mm beneath the rubbing surface,extensive microstructure evolution occurred by severe plastic deformation of the ferritic matrix,nodularisation and partial dissolution of the lamellar carbides,and internal oxidation.The microstructure evolution resulted in decreased surface hardness to HV0.3247 as compared to HV0.3284 of the bulk cast iron.
基金supported by the Natural Science Foundation of China(No.52271047)the Natural Science Foundation of Anhui Province(No.2208085ME106).
文摘Titanium alloys have been extensively applied due to their outstanding features,including high specific strength and corrosion resistance.However,the machining of these alloys presents challenges,leading to significant tool wear and reduced tool lifetime,ascribed to the difficult-to-machine features of Ti alloys.In the context of pursuing environmental sustainability and enhanced productivity,high-speed dry-cutting technology coupled with high-quality tool coatings are prospective.This paper comprehensively explores wear patterns and recent advancements in tool coatings for high-speed dry cutting of Ti-alloys.Key coating properties such as resistance to abrasion,adhesion,oxidation,fatigue,hot hardness,and self-adaptability are briefly introduced.Design strategies for enhancing micro-hardness,toughness,and adhesion,including nanocomposite,multilayer,and gradient architectures,are also discussed.Furthermore,the paper highlights several Boron(B)doped hard coatings as promising candidates for high-speed dry cutting against Ti-alloys,exploring the impact of B on microstructure,hardness,thermal stability,oxidation resistance,and lubrication.In summary,this work provides a systematic overview of novel B-doped tool coatings applied in highspeed dry cutting against Ti-alloys.
基金supported by Mitacs,InnoTech Alberta and Natural Science and Engineering Research Council(NSERC),CanadaStudy of hydrogen atom distribution at metallurgical microphases of X52 steel by scanning Kelvin probe force microscopy and finite element modelling.
文摘The work combined scanning Kelvin probe force microscopy measurements and finite element modelling to study the diffusion and distribution of hydrogen(H)atoms at metallurgical microphases contained in X52 pipeline steel.Results show that the pearlite contained in the steel is more stable than the ferrite during electropolishing,as indicated by the measured topographic profiles and Volta potentials.The hydrogen(H)-charging enhances the electrochemical activity of both pearlite and ferrite,as shown by increased Volta potential and thus the decreased work function.As the H-charging time increases,the Volta potentials of both phases further increase,implying that their activities increase with the H-charging time.The pearlite has a greater Volta potential and thus a lower work function than the ferrite.This is associated with more H atoms accumulating at the pearlite than at the ferrite.The H atom diffusion and accumulation are affected by H diffusivity at phase boundaries,H-trap binding energy and the number of traps in the steel.
文摘In this work,investigations were conducted into the adsorption behaviour and inhibitory effect of Mukia maderaspatana leaves extract on the corrosion of mild steel in 1.5M HCl solution at several temperatures.The techniques included chemical methods(weight loss measurements),surface analysis(SEM,FESEM)and solution analysis(UV–visible spectrophotometric,ICP-MS)techniques.The examination of the data revealed that the efficiency of inhibition rose as the inhibitor’s concentration increased and fell as the temperature increased.At 30 degrees Celsius,the concentration of inhibitor resulted in an increase in corrosion inhibition efficiency,reaching 99.02%efficiency at 8%concentration.The physical adsorption of the inhibitor on the metal surface was demonstrated by the adsorption free energy of the plant extract on mild steel.The conclusions above are supported by data from examinations of Scanning Electron Microscopy,FESEM,UV–visible and Fourier transform infrared spectrophotometry.
文摘Sericin is a highly hydrophilic macromolecular protein comprising 18 amino acids.It is considered biocompatible,nontoxic,and has antibacterial and antioxidant properties.It is applied on fabric,however,either the fabric needs to be pretreated with electrolytes or catalyst are used thereby increasing the number of processing steps.This study achieved sericin with multifunctional properties through chemical modification using cyanuric chloride.Modified sericin was applied in the dyeing stage along with the dyes on various textile substrates like wool,silk,and polyester.The functional properties were characterized by Fourier transform infrared and in modified sericin new chlorine peak at 779 cm−1 was obtained,X-ray diffractogram shows increase in crystallinity after modification of sericin,SEM showed particles of sericin on all fabrics even after 5 washes.Fabrics were analysed for antimicrobial activity and showed antimicrobial properties against gram negative and positive bacteria.Fastness properties and ultra violet protection factor of the samples were also determined.
基金supported by the National Natural Science Foundation of China(Grant numbers[52275427]).
文摘In recent years,the requirements for high-quality development in the manufacturing industry and extreme application conditions have increasingly demanded higher equipment performance.The surface and interface condition of components is directly related to the stability,reliability and service life of equipment.The development of high-performance or multi-performance surface texturing is of great significance for the effective improvement of mechanical properties,optical properties,catalytic properties and biological properties of surfaces.This paper summarizes the application of textured surfaces in improving the physical,chemical and biological properties of surfaces;outlines the types of texturing patterns and the design methods;analyzes the main technical methods and their characteristics for the preparation of surface textures in additive manufacturing,subtractive manufacturing and equal material manufacturing;and makes outlooks on texturing surfaces from the aspects of performance enhancement,pattern design and manufacturing technology in combination with the development trend of textured surfaces’intelligence and digitization.
基金National Natural Science Foundation of China(Nos.U2141212,52075460 and 52005117)Sichuan Science and Technology Program(Nos.2023NSFSC0411 and 2022023)the Fundamental Research Funds for the Central Universities(2682023ZTPY006,2682022CX043,2682022ZTPY014).
文摘This paper introduces the definition,classification,and running modes of fretting damage,as well as industrial phenomena of fretting damage cases.It is detail reviewed the progress of two-types fretting map theory(running condition fretting map-RCFM and material response fretting map-MRFM),and outlines the protection strategy of fretting wear according to the fretting map theory,i.e.eliminating the mixed fretting regime and slip regime,increasing the strength of the contact surface,reducing the coefficient of friction,and selecting and matching of materials.Several surface engineering techniques(such as PVD,laser surface modification technology,bonded solid lubricant coating,thermal spraying coating,and micro-arc oxidation coating)against fretting wear are reviewed,several mechanisms to alleviating fretting wear are proposed as well as a collection of practical examples of surface engineering designs to anti-fretting wear.Base on the review of previous studies,mechanisms of surface engineering technologies for alleviating fretting wear have been proposed.In addition,the content and process of surface engineering design are introduced in this paper.A quantitative evaluation method using polar coordinate diagram is applied to choose appropriate surface engineering technology.Finally,taking the locking pin of variable gauge train as an example,the process of surface engineering design is further expounded.
基金National Natural Science Foundation of China,21773212,Zhenhua ZhangJinhua Industrial Key Project,20221080,Zhenhua Zhangself-designed scientific research project of Zhejiang Normal University,2021ZS0602,Zhenhua Zhang.
文摘Catalytic CO_(2) hydrogenation to valuable chemicals is an excellent approach to address the increasingly serious“greenhouse effect”caused by CO_(2) emission generated from the utilizations of nonrenewable fossil energies,while such a process is limited by chemical inertia and thermal stability of the CO_(2) molecule and complex hydrogenation routes.In this review,we first summarized the recent progresses of metal-oxide nanocatalysts considered as a category of the most promising catalysts in CO_(2) hydrogenation to value-added C1 chemicals including CH_(4)/CO,formic acid/formate,and methanol.These studies involve with different structural factors affecting the metal-oxide interfacial catalysis including the structures of both the metals(type,particle size,morphology/crystal plane,and bimetal alloy)and the supports(type,particle size,crystal phase,morphology/crystal plane,and composite)and their(strong)metal-support interactions so as to identify the key factor determining the reaction activity,product selectivity,and catalytic stability in CO_(2) hydrogenation.Finally,we further discuss challenging coupling with future research opportunities for tunable interfacial catalysis of metal-oxide nanocatalysts in CO_(2) conversion.
基金support of the National Natural Science Foundation of China(52072236)National Natural Science Foundation of China(52002242)+1 种基金Science&Technology Commission of Shanghai Municipality and Shanghai Engineering Research Center of Ship Intelligent Maintenance and Energy Efficiency(20DZ2252300)Shanghai High-level Local University Innovation Team(Maritime safety&technical support).
文摘Icing as a regular natural phenomenon in life poses a serious threat to human production and life,traditional mechanical deicing,chemical deicing,and other methods have the shortcomings of high pollution,high energy consumption,and low efficiency,which limits their applicability and effectiveness of the scene of the above methods.With the expansion of global economic activities in recent years,the solution to the icing problem has become imminent.As a result,researchers have gradually deepened their studies related to anti-icing.Inspired by the lotus leaf effect,hogwash,polar,marine shellfish,and other natural organisms,anti-icing/deicing coatings can be designed functional biomimetic through both surface micro-nano structures and the physicochemical properties of the material.Superhydrophobic design is based on Young’s wetting equations,Wenzel’s wetting equations,and the Cassie-Baxter model of the superhydrophobic behavior of the interface formed by the liquid droplets and the surface,which prevents the droplets from spreading out and penetration to form heat exchange.The physicochemical properties are based on the slow-release behavior of chemical mediators inside the coating with properties such as super-lubrication and anti-freezing,which reduce the residence time and nucleation temperature of droplets on the surface.The coating effectively blocks the occurrence of icing behavior by passive means such as ultra-low interfacial wetting,interfacial slip,and lowering the freezing point of droplets,which has become a hot research direction.Meanwhile,the active anti-icing of photo-thermal,electro-thermal,phase change and other effects with the passive anti-icing to play a synergistic and complementary role for further enhance the anti-icing effect of the coating.To clarity the design mechanism and preparation process of the anti-icing/ice-removing surfaces,the article firstly classifies and introduces the coatings functioned according to the different mechanisms of action,and sums up the biomimetic super-hydrophobic design,the sacrificial type physicochemical characteristic.The article firstly classifies and introduces the functional types of coatings according to different mechanisms of action,and the latest research progress on the mechanism design of anti-icing coatings and their performance modification such as bionic superhydrophobic design,sacrificial physicochemical property design,microregion modulus control design and multifactorial coupling design were summarized.The problems of single-functionality and imbalance of performance of the existing coating mechanism design were analyzed and discussed,the view of the development trend and outlook of the development and application of icephobic coatings were put forward.
基金supported by the National Natural Science Foundation of China(Grant No.51901175)the China Postdoctoral Science Foundation funded project(No.2020T130499)the National Program for Support of Top-notch Young Professionals.
文摘Plasma spraying-physical vapor deposition(PS-PVD)and atmospheric plasma spraying(APS),as new thermal spraying process,could prepare advanced thermal barrier coatings by successive scanning deposition layer by layer.To investigate the layer structure of the coating,the transient in-situ deposit surface temperature was investigated by varying the scanning methods.Results show that,compared to unidirectional scanning method,alternating scanning method results in doubling heating duration,higher in-situ deposit temperature rising and thereby thicker well-bonded layer structure during each spray cycle for the coating deposited at the edge position of the scanning path.The erosion resistance of the coatings deposited by unidirectional scanning method is independent on deposition positions including edge position and center position.However,the erosion resistance of the coatings deposited at edge position by alternating scanning method is one time higher than those deposited by unidirectional scanning method.Finally,the erosion mechanism of layer spallation is revealed to explain the difference between different scanning methods.
基金funded by the National Natural Science Foundation of China(52101100)the General Project of Natural Science Research in Colleges and Universities of Jiangsu Province(21KJB430008)+1 种基金Yangzhou City-Yangzhou University Cooperation Foundation(YZ2023208)the Qing Lan Project of Yangzhou University(2022).
文摘The main issue with using biomass fuels in power plants is fireside corrosion.Applying corrosion-resistant coatings is one potential choice.The current study examines how a Ni-Al diffusion coating on austenitic stainless steel reacts to corrosion and interdiffusion(TP347H).Nickel was electrolytically deposited to create Ni-Al coatings,which were then pack aluminized at 650℃.With an internal layer of Ni and a Ni2Al3 outer layer,a homogenous and dense Ni-Al coating was created.Samples were heated to 560℃ for 168 h in an environment designed to simulate the combustion of biomass.A localized corrosion attack was the result.By using isothermal heat treatment in static air at 650℃ or 700℃ for up to 3000 h,interdiffusion was examined.In the course of the interdiffusion process,the Ni2Al3 eventually changed into NiAl and Ni3Al.At both temperatures,porosity formed at the intersection of the Ni-Al coating and the Ni layer and grew with time.
基金supported by the National Natural Science Foundation of China(Grant No.52105433)the National Natural Science Foundation of China(Grant No.52175383)the Henan Key Laboratory of Superhard Abrasives and Grinding Equipment,Henan University of Technology,China(JDKFJJ2022006).
文摘Grinding is a generally utilized method,removing excess materials through effective abrasives.The grinding abrasives with multiple shape-position characteristics play a dominant role in determining the thermo-mechanical coupling,which may influence the surface quality directly.To investigate this correlated influence mechanism,this paper focuses on the abrasive shape and position characteristic on the grinding thermo-mechanical process with the analytic single abrasive interaction force model by considering the abrasive shape and its distribution information.It can be found that the mapped dynamic grinding temperature is actually discretized on the workpiece surface,which is on account of the diversity of the abrasive shape and its distribution.Moreover,higher spherical and conical abrasive particles,as well as lower pyramid shaped abrasive particle ratios,can generate greater specific grinding energy with a discretized temperature distribution,when compared with a higher proportion of pyramid shaped abrasive.The study can be utilized to provide valuable theoretical foundation for engineering practice by preparing structural wheel and its grinding property.
