The process of electroplating Co-Ce alloys on the nickel foam framework surface can improve electro-conductivity for active materials and nickel substrate interface. The results of inductive coupled plasma emission sp...The process of electroplating Co-Ce alloys on the nickel foam framework surface can improve electro-conductivity for active materials and nickel substrate interface. The results of inductive coupled plasma emission spectrometer (ICP), cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA) indicate that the Co-Ce coating chemical content of rare earth Ce 0.19wt.%-0.28wt.% can not only alter the microstructure of electroplating coating, but also accelerate the oxidation reaction of Co and improve its transfer rate of electric current conductivity to the active material particles. The grads-like distributing electro-conductive network of CoOOH is formed on the nickel substrate surface, which improves reversibility of pasted nickel electrode. The charging receptivity is improved by Co-Ce coating on the pasted nickel electrode substrate, and its specific discharging capacity is improved by 50%.展开更多
Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon ...Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon steel substrates via photo-assisted electrodeposition.A systematic investigation was conducted on the effects of cerium ion concentration and nano-ceria(CeO_(2))particle content in the electrolyte on the coating properties,along with an analysis of the temporal evolution of coating’s corrosion resistance.When the cerium ion concentration in the electrolyte was 0.05 mol/L,the coating exhibited a uniform black appearance with a light absorption rate of 95%,an emissivity of 0.87,maximum impedance,and the lowest corrosion tendency,demonstrating optimal comprehensive performance.The coating prepared with a nano-ceria concentration of 6 g/L in the electrolyte exhibited an emissivity of 0.9,achieved a 5B adhesion grade(ASTM D3359-09),and demonstrated a one-order-of-magnitude reduction in corrosion current density compared to coatings fabricated without nano-ceria in the electrolyte.With prolonged storage time,the coating's impedance slightly increased,leading to improved corrosion resistance.展开更多
To mitigate the impact of interdiffusion reactions between the silicide slurry and Ta12W alloy substrate during vacuum sintering process on the oxidation resistance of the silicide coating,a micro-arc oxidation pretre...To mitigate the impact of interdiffusion reactions between the silicide slurry and Ta12W alloy substrate during vacuum sintering process on the oxidation resistance of the silicide coating,a micro-arc oxidation pretreatment was employed to construct a Ta_(2)O_(5)ceramic layer on the Ta12W alloy surface.Subsequently,a slurry spraying-vacuum sintering method was used to prepare a Si-Cr-Ti-Zr coating on the pretreated substrate.Comparative studies were conducted on the microstructure,phase composition,and isothermal oxidation resistance(at 1600℃)of the as-prepared coatings with and without the micro-arc oxidation ceramic layer.The results show that the Ta_(2)O_(5)layer prepared at 400 V is more continuous and has smaller pores than that prepared at 350 V.After microarc oxidation pretreatment,the Si-Cr-Ti-Zr coating on Ta12W alloy consists of three distinct layers:an upper layer dominated by Ti_(5)Si_(3),Ta_(5)Si_(3),and ZrSi;a middle layer dominated by TaSi_(2);a coating/substrate interfacial reaction layer dominated by Ta_(5)Si_(3).Both the Si-Cr-Ti-Zr coatings with and without the Ta_(2)O_(5)ceramic layer do not fail after isothermal oxidation at 1600℃for 5 h.Notably,the addition of the Ta2O5 ceramic layer reduces the high-temperature oxidation rate of the coating.展开更多
TiB_(2)coatings can significantly enhance the high-temperature oxidation resistance of molybdenum,which would broaden the application range of molybdenum and alloys thereof.However,traditional methods for preparing Ti...TiB_(2)coatings can significantly enhance the high-temperature oxidation resistance of molybdenum,which would broaden the application range of molybdenum and alloys thereof.However,traditional methods for preparing TiB_(2)coatings have disadvantages such as high equipment costs,complicated processes,and highly toxic gas emissions.This paper proposes an environmentally friendly method,which requires inexpensive equipment and simple processing,for preparing TiB_(2)coating on molybdenum via electrophoretic deposition within Na3AlF6-based molten salts.The produced TiB_(2)layer had an approximate thickness of 60μm and exhibited high density,outstanding hardness(38.2 GPa)and robust adhesion strength(51 N).Additionally,high-temperature oxidation experiments revealed that,at900℃,the TiB_(2)coating provided effective protection to the molybdenum substrate against oxidation for 3 h.This result indicates that the TiB_(2)coating prepared on molybdenum using molten salt electrophoretic deposition possesses good high-temperature oxidation resistance.展开更多
The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstru...The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.展开更多
The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction int...The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction interface temperature and axial displacement—time curves during rotary friction process were measured.The results showed that all the curves firstly experienced rising stage and then steady stage.The rising stage corresponded to sliding friction while the steady stage corresponded to viscoplastic friction.After viscoplastic friction processing,three typical zones of viscoplastic deformation zone,thermo-mechanically affected zone,and original laser-clad zone can be observed successively from the friction surface to the interior.The viscoplastic deformation significantly crushed the network M23C7 phase in original laser-clad zone and made it dispersively distributed with equiaxial shape and in nano-scale.The viscoplastic zone,in width of 37-131 μm,is mainly characterized by refined M23C7 and α-Co phase with grain size bellow 50 nm,and even a small quantity of amorphous.Thus,the hardness of viscoplastic zone about HV997 was improved compared with the hardness of original laser-clad zone about HV600.展开更多
The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties ...The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipol...Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipolar plates(BPs),one of the core components in PEMWE cells.In this work,NbN coatings are deposited on Ti BPs by magnetron sputtering to improve the corrosion resistance and conductivity,for which the critical process parameters,such as the working pressure,partial nitrogen pressure and de-position temperature are well optimized.It is found that the compact microstructure,highly conductive δ-NbN and uniform nanoparticles play a dominant role in the synergistic improvement of the corrosion resistance and electrical conductivity of NbN coatings.The optimized NbN coatings exhibit excellent cor-rosion resistance with the low corrosion current density of 1.1×10^(-8) A cm^(-2),a high potential value of-0.005 V vs.SCE and a low ICR value of 15.8 mΩcm2@1.5 MPa.Accordingly,NbN coatings can be a promising candidate for the development of the low-cost and high-anti-corrosion Ti BPs of PEMWE.展开更多
The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocit...The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocity oxygen fuel thermal spraying. The phase constitution, elemental distribution and microstructure of the coating were characterized by X-ray diffraction and transmission electron microscopy, respectively. The wear resistance and corrosion resistance of the prepared composite coating were tested. The results show that the main phases of the coating include WC, binding phase with partial amorphous structure, with a little WC and Co(Cr)coexisting. The distributions of Co and Cr elements from the phase boundary to the eutectic area then to Co zone were analyzed quantitatively. The mechanisms for the formation of the microstructure and effects of Cr on the performance of the composite coating are proposed.展开更多
To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)t...To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)through an environmentally friendly,simple and low-cost process.High-density amino-branched PEI and highly adhesive PDA formed covalent bond cross-links with GO(PDA/PEI-GO)through the Michael addition and Schiffbase reactions.With the introduction of amino active sites,the PDA self-polymerization reaction time was significantly shorted from 24 to 6 h.The covalently cross-linked network increased the lamellar spacing of GO and enhanced the interfacial bonds between the PDA/PEI-GO lamellae and EP matrix.Due to the improved dispersion and surface activity of GO,the PDA/PEI-GO nano-filled EP coating exhibited excellent wear resistance.Reciprocating friction with GCr15 stainless steel ball,the average friction coefficient and wear rate of the coating were reduced by 31.9%and 62.7%,respectively,compared to the pure EP coating.In addition,the wear mechanism of the PDA/PEI-GO/EP coating changed from adhesive and fatigue wear to abrasive wear,and it maintained good wear resistance by forming a GO lubrication transfer film on the counterpart surface.Therefore,this study may provide a new strategy for improving the dispersion of graphene in wear-resistant polymer materials for practical applications.展开更多
The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has...The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.展开更多
Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,...Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.展开更多
Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and fr...Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and friction behavior of diamond coatings can impede their ability to meet the demanding requirements of advanced engineering surfaces.This study proposed the thermal stress control at coating interfaces and demonstrated a novel process of precise graphenization on conventional diamond coatings surface through laser induction and mechanical cleavage,without causing damage to the metal substrate.Through experiments and simulations,the influence mechanism of surface graphitization and interfacial thermal stress was elucidated,ultimately enabling rapid conversion of the diamond coating surface to graphene while controlling the coating’s thickness and roughness.Compared to the original diamond coatings,the obtained surfaces exhibited a 63%-72%reduction in friction coefficients,all of which were below 0.1,with a minimum of 0.06,and a 59%-67%decrease in specific wear rates.Moreover,adhesive wear in the friction counterpart was significantly inhibited,resulting in a reduction in wear by 49%-83%.This demonstrated a significant improvement in lubrication and inhibition of mechanochemical wear properties.This study provides an effective and cost-efficient avenue to overcome the application bottleneck of engineered diamond surfaces,with the potential to significantly enhance the performance and expand the application range of diamond-coated components.展开更多
WC particles reinforced CoCrFeNiMo high-entropy alloy(HEA)composite coatings were prepared on Cr12MoV steel successfully by laser cladding technology to improve the wear resistance of substrates.Effect of WC content o...WC particles reinforced CoCrFeNiMo high-entropy alloy(HEA)composite coatings were prepared on Cr12MoV steel successfully by laser cladding technology to improve the wear resistance of substrates.Effect of WC content on microstructure and wear property of the composite coatings was studied in detail.Large numbers of carbides with four main types:primary carbide crystals,eutectic structures,massive crystals growing along the periphery of the remaining WC particles and incompletely fused WC particles,were found to exist in the WC/CoCrFeNiMo composite coatings.With increasing WC content,the microhardness of coatings is gradually improved while the average friction coefficients follow the opposite trend due to solid solution strengthening and second phase strengthening effect.The maximum microhardness and minimum friction coefficient are HV_(0.2)689.7 and 0.72,respectively,for the composite coating with 30 wt.%WC,the wear resistance of the substrate is improved significantly,the wear mechanisms are spalling wear and abrasive wear due to their high microhardness.展开更多
The phase composition of Co-30Cr-6Al-0.5Y coating deposited by planar magnetron sputtering as well as the effect of sputtering parameters on it have been investigated.The sputtered coating is composed of hep ε-phase ...The phase composition of Co-30Cr-6Al-0.5Y coating deposited by planar magnetron sputtering as well as the effect of sputtering parameters on it have been investigated.The sputtered coating is composed of hep ε-phase of fcc α-phase of Co solid solution with a mi- nority of β-CoAl intermetallic phase.The hcp ε-Co phase and the fcc χ-Co phase assumed a <100>and <110>preferred orientation respectively.Both the phase type and orientation extent depend on the sputtering parameters.If the substrate surface is parallel to the target face during sputtering,the coating will be of fine crystallite with compact structure and smooth surface;if it is rotated,the coating will be to the contrary.展开更多
Polyurethane-fluorinated polysiloxane(PU-^(F)PDMS)with high-strength,high-bonding and low surface en-ergy is synthesized as the matrix,and the PU-^(F)PDMS/MCs/Ag marine anti-fouling coating on the sur-face of imitatio...Polyurethane-fluorinated polysiloxane(PU-^(F)PDMS)with high-strength,high-bonding and low surface en-ergy is synthesized as the matrix,and the PU-^(F)PDMS/MCs/Ag marine anti-fouling coating on the sur-face of imitation crab shells is constructed by assembling butenolide@1,1-stilbene-modified hydrolyzed polyglycidyl methacrylate/graphene oxide microcapsules(Bu@PGMAm/GO MCs)with compact multi-shell structure and Ag nanoparticles(AgNPs)step by step on the PU-^(F)PDMS matrix.The PU-^(F)PDMS/MCs/Ag bionic anti-fouling coatings achieve long-term and stable anti-fouling effect under the combination of robust low-surface-energy PU-^(F)PDMS matrix,steady-state sustained release of butenolide encapsulated by the compact multi-shell,bionic surface formed by the microcapsules and AgNPs,and the release of Ag^(+).The shear strength,tensile strength,and elongation at break of the PU-^(F)PDMS/MCs/Ag are 3.53 MPa,6.7 MPa,and 192.83%,respectively.Its static contact angle and sliding angle are 161.8°and 3.6°,respectively.The antibacterial rate of PU-^(F)PDMS/MCs/Ag against Escherichia coli,Staphylococcus aureus,and Candida albicans can reach 100%.Compared with glass blank,PU,PU-^(F)PDMS,PU-^(F)PDMS/Ag,and PU-^(F)PDMS/MCs,both the adhesion number and coverage percentage of chlorella adhere to PU-^(F)PDMS/MCs/Ag are the minimum values,which are 600 cell mm^(-2) and 1.53%,respectively.After 6 months of marine field test,the primer blank,PU,PU-^(F)PDMS all show different degrees of attachment by shellfish,spirorbis,al-gae and other biofouling,while the PU-^(F)PDMS/MCs/Ag coating is still not covered with biofouling,while the PU-^(F)PDMS/MCs/Ag coatings still exhibit little attachment of marine fouling.The PU-^(F)PDMS/MCs/Ag bionic anti-fouling coatings are expected to be widely used in the fields of anti-fouling,anti-icing,anti-fogging,drag reduction,self-cleaning,and antibacterial.展开更多
We have developed a superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating on the surface of Mg alloy.This composite comprised a tungstate-intercalated(LDH-W)underlayer that was grown at low temperatu...We have developed a superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating on the surface of Mg alloy.This composite comprised a tungstate-intercalated(LDH-W)underlayer that was grown at low temperature(relative to hydrothermal reaction conditions)under atmospheric pressure and an outer polysiloxane layer created from a solution containing perfluorodecyltrimethoxysilane(PFDTMS)using a simple immersion method.The successful intercalation of tungstate into the LDH phase and the following formation of the polysiloxane layer were confirmed through X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the LDH-W film,both before and after the PFDTMS modification,was evaluated using electrochemical impedance spectroscopy(EIS),Tafel curves,and immersion experiments.The results showed that Mg coated with LDH-W/PFDTMS exhibited significantly enhanced corrosion protection compared to the unmodified LDHW film,with no apparent signs of corrosion after exposure to 3.5wt%NaCl solution for 15 d.Furthermore,the LDH-W/PFDTMS coating demonstrated superior superhydrophobicity and self-cleaning properties against water and several common beverages,as confirmed by static contact angle and water-repellency tests.These results offer valuable insights into preparing superhydrophobic and corrosion-resistant LDH-based composite coatings on Mg alloy surfaces under relatively mild reaction conditions.展开更多
Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical enginee...Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical engineering.Unfortunately,the poor corrosion resistance of Mg-alloys limits their wide acceptance.Advanced composite coatings which are self-healing,superhydrophobic anti corrosive,and wear resistant are new synthetic materials for abating these challenges.The superimposed superhydrophobic surfaces help in minimizing their water contact,thus slowing down the electrochemical reactions on the surface of the alloys,while their self-healing characteristics autonomously aid in the repair of any induced micro-crack,defect or damage towards ensuring the metal's long-term protection.In addition,the integration of wear-resistant materials further improves the durability of coatings under mechanical stress.The most recent research efforts have been directed towards the preparation of multifunctional composites,with an emphasis on nanomaterials,functional polymers,and state-of-the-art fabrication techniques in order to take advantage of their synergistic effects.Some of the methods that have so far exhibited promising potentials in fabricating these materials include the sol-gel method,layer-by-layer assembly,and plasma treatments.However,most of the fabricated products are still faced with significant challenges ranging from long-term stability to homogeneous adhesion of the coatings and their scalability for industrial applications.This review discusses the recent progress and the relationship between corrosion inhibition and self-healing efficiencies of wear resistant polymer nanocomposite coatings.Some challenges related to optimizing coating performance were also discussed.In addition,future directions ranging from the consideration of bioinspired designs,novel hybrid nanocomposite materials,and environmentally sustainable solutions integrated with smart protective coatings were also proposed as new wave technologies that can potentially revolutionize the corrosion protection offered by Mg alloys while opening up prospects for improved performance and sustainability.展开更多
Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor ...Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.展开更多
文摘The process of electroplating Co-Ce alloys on the nickel foam framework surface can improve electro-conductivity for active materials and nickel substrate interface. The results of inductive coupled plasma emission spectrometer (ICP), cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA) indicate that the Co-Ce coating chemical content of rare earth Ce 0.19wt.%-0.28wt.% can not only alter the microstructure of electroplating coating, but also accelerate the oxidation reaction of Co and improve its transfer rate of electric current conductivity to the active material particles. The grads-like distributing electro-conductive network of CoOOH is formed on the nickel substrate surface, which improves reversibility of pasted nickel electrode. The charging receptivity is improved by Co-Ce coating on the pasted nickel electrode substrate, and its specific discharging capacity is improved by 50%.
文摘Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon steel substrates via photo-assisted electrodeposition.A systematic investigation was conducted on the effects of cerium ion concentration and nano-ceria(CeO_(2))particle content in the electrolyte on the coating properties,along with an analysis of the temporal evolution of coating’s corrosion resistance.When the cerium ion concentration in the electrolyte was 0.05 mol/L,the coating exhibited a uniform black appearance with a light absorption rate of 95%,an emissivity of 0.87,maximum impedance,and the lowest corrosion tendency,demonstrating optimal comprehensive performance.The coating prepared with a nano-ceria concentration of 6 g/L in the electrolyte exhibited an emissivity of 0.9,achieved a 5B adhesion grade(ASTM D3359-09),and demonstrated a one-order-of-magnitude reduction in corrosion current density compared to coatings fabricated without nano-ceria in the electrolyte.With prolonged storage time,the coating's impedance slightly increased,leading to improved corrosion resistance.
基金National Natural Science Foundation of China(52071274)Key Research and Development Projects of Shaanxi Province(2023-YBGY-442)Science and Technology Nova Project-Innovative Talent Promotion Program of Shaanxi Province(2020KJXX-062)。
文摘To mitigate the impact of interdiffusion reactions between the silicide slurry and Ta12W alloy substrate during vacuum sintering process on the oxidation resistance of the silicide coating,a micro-arc oxidation pretreatment was employed to construct a Ta_(2)O_(5)ceramic layer on the Ta12W alloy surface.Subsequently,a slurry spraying-vacuum sintering method was used to prepare a Si-Cr-Ti-Zr coating on the pretreated substrate.Comparative studies were conducted on the microstructure,phase composition,and isothermal oxidation resistance(at 1600℃)of the as-prepared coatings with and without the micro-arc oxidation ceramic layer.The results show that the Ta_(2)O_(5)layer prepared at 400 V is more continuous and has smaller pores than that prepared at 350 V.After microarc oxidation pretreatment,the Si-Cr-Ti-Zr coating on Ta12W alloy consists of three distinct layers:an upper layer dominated by Ti_(5)Si_(3),Ta_(5)Si_(3),and ZrSi;a middle layer dominated by TaSi_(2);a coating/substrate interfacial reaction layer dominated by Ta_(5)Si_(3).Both the Si-Cr-Ti-Zr coatings with and without the Ta_(2)O_(5)ceramic layer do not fail after isothermal oxidation at 1600℃for 5 h.Notably,the addition of the Ta2O5 ceramic layer reduces the high-temperature oxidation rate of the coating.
基金supported by the Original Exploratory Program of the National Natural Science Foundation of China(No.52450012)。
文摘TiB_(2)coatings can significantly enhance the high-temperature oxidation resistance of molybdenum,which would broaden the application range of molybdenum and alloys thereof.However,traditional methods for preparing TiB_(2)coatings have disadvantages such as high equipment costs,complicated processes,and highly toxic gas emissions.This paper proposes an environmentally friendly method,which requires inexpensive equipment and simple processing,for preparing TiB_(2)coating on molybdenum via electrophoretic deposition within Na3AlF6-based molten salts.The produced TiB_(2)layer had an approximate thickness of 60μm and exhibited high density,outstanding hardness(38.2 GPa)and robust adhesion strength(51 N).Additionally,high-temperature oxidation experiments revealed that,at900℃,the TiB_(2)coating provided effective protection to the molybdenum substrate against oxidation for 3 h.This result indicates that the TiB_(2)coating prepared on molybdenum using molten salt electrophoretic deposition possesses good high-temperature oxidation resistance.
基金supported by the National Natural Science Foundation of China(Nos.52105330,52175307)the Natural Science Foundation of Shandong Province,China(No.ZR2023JQ021)。
文摘The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.
基金Project(51101126) supported by the National Natural Science Foundation of ChinaProjects(20110491684,2012T50817) supported by the China Postdoctoral Science FoundationProject(20110942K) supported by the Open Fund of State Key Laboratory of Powder Metallurgy,China
文摘The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction interface temperature and axial displacement—time curves during rotary friction process were measured.The results showed that all the curves firstly experienced rising stage and then steady stage.The rising stage corresponded to sliding friction while the steady stage corresponded to viscoplastic friction.After viscoplastic friction processing,three typical zones of viscoplastic deformation zone,thermo-mechanically affected zone,and original laser-clad zone can be observed successively from the friction surface to the interior.The viscoplastic deformation significantly crushed the network M23C7 phase in original laser-clad zone and made it dispersively distributed with equiaxial shape and in nano-scale.The viscoplastic zone,in width of 37-131 μm,is mainly characterized by refined M23C7 and α-Co phase with grain size bellow 50 nm,and even a small quantity of amorphous.Thus,the hardness of viscoplastic zone about HV997 was improved compared with the hardness of original laser-clad zone about HV600.
基金financially supported by the National Natural Science Foundation of China(No.52371049)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(YESS,No.2020QNRC001)the National Science and Technology Resources Investigation Program of China(Nos.2021FY100603 and 2019FY101404)。
文摘The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
基金supported by the National Key Re-search and Development Program of China(No.2022YFB4002100)the National Natural Science Foundation of China(No.52271136)the Natural Science Foundation of Shaanxi Province(Nos.2019TD-020 and 2021JC-06).
文摘Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipolar plates(BPs),one of the core components in PEMWE cells.In this work,NbN coatings are deposited on Ti BPs by magnetron sputtering to improve the corrosion resistance and conductivity,for which the critical process parameters,such as the working pressure,partial nitrogen pressure and de-position temperature are well optimized.It is found that the compact microstructure,highly conductive δ-NbN and uniform nanoparticles play a dominant role in the synergistic improvement of the corrosion resistance and electrical conductivity of NbN coatings.The optimized NbN coatings exhibit excellent cor-rosion resistance with the low corrosion current density of 1.1×10^(-8) A cm^(-2),a high potential value of-0.005 V vs.SCE and a low ICR value of 15.8 mΩcm2@1.5 MPa.Accordingly,NbN coatings can be a promising candidate for the development of the low-cost and high-anti-corrosion Ti BPs of PEMWE.
基金financially supported by the National Natural Science Foundation (No. 51601004)the Key Program of National Natural Science Foundation (No. 51631002)the National Science Fund for Distinguished Young Scholars (No. 51425101)
文摘The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocity oxygen fuel thermal spraying. The phase constitution, elemental distribution and microstructure of the coating were characterized by X-ray diffraction and transmission electron microscopy, respectively. The wear resistance and corrosion resistance of the prepared composite coating were tested. The results show that the main phases of the coating include WC, binding phase with partial amorphous structure, with a little WC and Co(Cr)coexisting. The distributions of Co and Cr elements from the phase boundary to the eutectic area then to Co zone were analyzed quantitatively. The mechanisms for the formation of the microstructure and effects of Cr on the performance of the composite coating are proposed.
基金This work was financially supported by the Shanxi Province Science and Technology Major Project for New Materials Tech-nology(No.20181102014)the Shanxi Province 1331 Project Key Innovation Team of Polymeric Functional New Materials,the Natural Science Foundation of Shanxi Province of China(No.20210302123036)the Program for the Excellent Young Aca-demic Leaders of Higher Learning Institutions of Shanxi Province.
文摘To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)through an environmentally friendly,simple and low-cost process.High-density amino-branched PEI and highly adhesive PDA formed covalent bond cross-links with GO(PDA/PEI-GO)through the Michael addition and Schiffbase reactions.With the introduction of amino active sites,the PDA self-polymerization reaction time was significantly shorted from 24 to 6 h.The covalently cross-linked network increased the lamellar spacing of GO and enhanced the interfacial bonds between the PDA/PEI-GO lamellae and EP matrix.Due to the improved dispersion and surface activity of GO,the PDA/PEI-GO nano-filled EP coating exhibited excellent wear resistance.Reciprocating friction with GCr15 stainless steel ball,the average friction coefficient and wear rate of the coating were reduced by 31.9%and 62.7%,respectively,compared to the pure EP coating.In addition,the wear mechanism of the PDA/PEI-GO/EP coating changed from adhesive and fatigue wear to abrasive wear,and it maintained good wear resistance by forming a GO lubrication transfer film on the counterpart surface.Therefore,this study may provide a new strategy for improving the dispersion of graphene in wear-resistant polymer materials for practical applications.
文摘The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.
基金supported by the National Key R&D Pro-gram of China(Grant No.2021YFA0715803)the National Natural Science Foundation of China(Grant Nos.52293373,52130205,and 52302091)+1 种基金the Joint Fund of Henan Province Science and Technol-ogy R&D Program(No.225200810002)the ND Basic Research Funds of Northwestern Polytechnical University(No.G2022WD).
文摘Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.
基金support from the National Natural Science Foundation of China(NSFC)[No.52475464,52475463]National Natural Science Foundation of Jiangsu Province(No.BK20231442)+4 种基金the Fundamental Research Funds for the Central Universities(No.NS2024032)the International Joint Laboratory of Sustainable Manufacturing,Ministry of Education and the Fundamental Research Funds for the Central Universities(No.NG2024007)China Scholarship Council(No.202206830048)the Foundation of the Graduate Innovation Center,Nanjing University of Aeronautics and Astronautics(No.kfjj20200510)Funding for Outstanding Doctoral Dissertation in NUAA(No.BCXJ23-09)。
文摘Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and friction behavior of diamond coatings can impede their ability to meet the demanding requirements of advanced engineering surfaces.This study proposed the thermal stress control at coating interfaces and demonstrated a novel process of precise graphenization on conventional diamond coatings surface through laser induction and mechanical cleavage,without causing damage to the metal substrate.Through experiments and simulations,the influence mechanism of surface graphitization and interfacial thermal stress was elucidated,ultimately enabling rapid conversion of the diamond coating surface to graphene while controlling the coating’s thickness and roughness.Compared to the original diamond coatings,the obtained surfaces exhibited a 63%-72%reduction in friction coefficients,all of which were below 0.1,with a minimum of 0.06,and a 59%-67%decrease in specific wear rates.Moreover,adhesive wear in the friction counterpart was significantly inhibited,resulting in a reduction in wear by 49%-83%.This demonstrated a significant improvement in lubrication and inhibition of mechanochemical wear properties.This study provides an effective and cost-efficient avenue to overcome the application bottleneck of engineered diamond surfaces,with the potential to significantly enhance the performance and expand the application range of diamond-coated components.
基金Project(2021YFC2801904)supported by the National Key R&D Program of ChinaProject(KY10100230067)supported by the Basic Product Innovation Research Project,China+3 种基金Projects(52271130,52305344)supported by the National Natural Science Foundation of ChinaProjects(ZR2020ME017,ZR2020QE186)supported by the Natural Science Foundation of Shandong Province,ChinaProjects(AMGM2024F11,AMGM2021F10,AMGM2023F06)supported by the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai,ChinaProject(KY90200210015)supported by Leading Scientific Research Project of China National Nuclear Corporation(CNNC),China。
文摘WC particles reinforced CoCrFeNiMo high-entropy alloy(HEA)composite coatings were prepared on Cr12MoV steel successfully by laser cladding technology to improve the wear resistance of substrates.Effect of WC content on microstructure and wear property of the composite coatings was studied in detail.Large numbers of carbides with four main types:primary carbide crystals,eutectic structures,massive crystals growing along the periphery of the remaining WC particles and incompletely fused WC particles,were found to exist in the WC/CoCrFeNiMo composite coatings.With increasing WC content,the microhardness of coatings is gradually improved while the average friction coefficients follow the opposite trend due to solid solution strengthening and second phase strengthening effect.The maximum microhardness and minimum friction coefficient are HV_(0.2)689.7 and 0.72,respectively,for the composite coating with 30 wt.%WC,the wear resistance of the substrate is improved significantly,the wear mechanisms are spalling wear and abrasive wear due to their high microhardness.
文摘The phase composition of Co-30Cr-6Al-0.5Y coating deposited by planar magnetron sputtering as well as the effect of sputtering parameters on it have been investigated.The sputtered coating is composed of hep ε-phase of fcc α-phase of Co solid solution with a mi- nority of β-CoAl intermetallic phase.The hcp ε-Co phase and the fcc χ-Co phase assumed a <100>and <110>preferred orientation respectively.Both the phase type and orientation extent depend on the sputtering parameters.If the substrate surface is parallel to the target face during sputtering,the coating will be of fine crystallite with compact structure and smooth surface;if it is rotated,the coating will be to the contrary.
基金supported by the National Natural Science Foundation of China(Nos.52003148 and 52261045)the State Key Laboratory of Marine Resource Utilization in South China Sea,Hainan University(No.MRUKF2021023)+3 种基金the Key Research and Development Project of Shaanxi Province(No.2023-YBGY-475)the Key Scientific Research Project of Education Department of Shaanxi Province(No.22JS003)the Industrialization Project of the State Key Laboratory of Biological Resources and Ecological Environment(Cultivation)of Qinba Region(No.SXC-2310)the key cultivation project funds of Shaanxi University of Technology(No.SLGKYXM2201).
文摘Polyurethane-fluorinated polysiloxane(PU-^(F)PDMS)with high-strength,high-bonding and low surface en-ergy is synthesized as the matrix,and the PU-^(F)PDMS/MCs/Ag marine anti-fouling coating on the sur-face of imitation crab shells is constructed by assembling butenolide@1,1-stilbene-modified hydrolyzed polyglycidyl methacrylate/graphene oxide microcapsules(Bu@PGMAm/GO MCs)with compact multi-shell structure and Ag nanoparticles(AgNPs)step by step on the PU-^(F)PDMS matrix.The PU-^(F)PDMS/MCs/Ag bionic anti-fouling coatings achieve long-term and stable anti-fouling effect under the combination of robust low-surface-energy PU-^(F)PDMS matrix,steady-state sustained release of butenolide encapsulated by the compact multi-shell,bionic surface formed by the microcapsules and AgNPs,and the release of Ag^(+).The shear strength,tensile strength,and elongation at break of the PU-^(F)PDMS/MCs/Ag are 3.53 MPa,6.7 MPa,and 192.83%,respectively.Its static contact angle and sliding angle are 161.8°and 3.6°,respectively.The antibacterial rate of PU-^(F)PDMS/MCs/Ag against Escherichia coli,Staphylococcus aureus,and Candida albicans can reach 100%.Compared with glass blank,PU,PU-^(F)PDMS,PU-^(F)PDMS/Ag,and PU-^(F)PDMS/MCs,both the adhesion number and coverage percentage of chlorella adhere to PU-^(F)PDMS/MCs/Ag are the minimum values,which are 600 cell mm^(-2) and 1.53%,respectively.After 6 months of marine field test,the primer blank,PU,PU-^(F)PDMS all show different degrees of attachment by shellfish,spirorbis,al-gae and other biofouling,while the PU-^(F)PDMS/MCs/Ag coating is still not covered with biofouling,while the PU-^(F)PDMS/MCs/Ag coatings still exhibit little attachment of marine fouling.The PU-^(F)PDMS/MCs/Ag bionic anti-fouling coatings are expected to be widely used in the fields of anti-fouling,anti-icing,anti-fogging,drag reduction,self-cleaning,and antibacterial.
基金supported by the National Natural Science Foundation of China(No.52271073)the Sichuan Provincial Natural Science Foundation for Distinguished Young Scholars,China(No.2024NSFJQ0034)the Innovation Team Funds of China West Normal University(No.KCXTD2024-1)。
文摘We have developed a superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating on the surface of Mg alloy.This composite comprised a tungstate-intercalated(LDH-W)underlayer that was grown at low temperature(relative to hydrothermal reaction conditions)under atmospheric pressure and an outer polysiloxane layer created from a solution containing perfluorodecyltrimethoxysilane(PFDTMS)using a simple immersion method.The successful intercalation of tungstate into the LDH phase and the following formation of the polysiloxane layer were confirmed through X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the LDH-W film,both before and after the PFDTMS modification,was evaluated using electrochemical impedance spectroscopy(EIS),Tafel curves,and immersion experiments.The results showed that Mg coated with LDH-W/PFDTMS exhibited significantly enhanced corrosion protection compared to the unmodified LDHW film,with no apparent signs of corrosion after exposure to 3.5wt%NaCl solution for 15 d.Furthermore,the LDH-W/PFDTMS coating demonstrated superior superhydrophobicity and self-cleaning properties against water and several common beverages,as confirmed by static contact angle and water-repellency tests.These results offer valuable insights into preparing superhydrophobic and corrosion-resistant LDH-based composite coatings on Mg alloy surfaces under relatively mild reaction conditions.
文摘Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical engineering.Unfortunately,the poor corrosion resistance of Mg-alloys limits their wide acceptance.Advanced composite coatings which are self-healing,superhydrophobic anti corrosive,and wear resistant are new synthetic materials for abating these challenges.The superimposed superhydrophobic surfaces help in minimizing their water contact,thus slowing down the electrochemical reactions on the surface of the alloys,while their self-healing characteristics autonomously aid in the repair of any induced micro-crack,defect or damage towards ensuring the metal's long-term protection.In addition,the integration of wear-resistant materials further improves the durability of coatings under mechanical stress.The most recent research efforts have been directed towards the preparation of multifunctional composites,with an emphasis on nanomaterials,functional polymers,and state-of-the-art fabrication techniques in order to take advantage of their synergistic effects.Some of the methods that have so far exhibited promising potentials in fabricating these materials include the sol-gel method,layer-by-layer assembly,and plasma treatments.However,most of the fabricated products are still faced with significant challenges ranging from long-term stability to homogeneous adhesion of the coatings and their scalability for industrial applications.This review discusses the recent progress and the relationship between corrosion inhibition and self-healing efficiencies of wear resistant polymer nanocomposite coatings.Some challenges related to optimizing coating performance were also discussed.In addition,future directions ranging from the consideration of bioinspired designs,novel hybrid nanocomposite materials,and environmentally sustainable solutions integrated with smart protective coatings were also proposed as new wave technologies that can potentially revolutionize the corrosion protection offered by Mg alloys while opening up prospects for improved performance and sustainability.
基金supported by the National Natural Science Foundation of China(Nos.U21B2053,52071114,52001100,and 523B2010)Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(No.YQ2023E008)+1 种基金Young Elite Scientists Sponsorship Program by CAST(NO.2021QNRC001)Heilongjiang Touyan Team Program.
文摘Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.
