To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxida...To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.展开更多
To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth...To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth structure,microstructure,and tribological properties of TTOs with Ti target power was studied.After the erosion test,the variation of erosion damage behavior of TTOs with mechanical properties under different erosion conditions was further studied.The results show that the TTOs eliminate the roughness,voids,and defects in the material due to the mobility of the adsorbed atoms during the growth process,and a flat and dense smooth surface is obtained.Tribological tests show that the TTOs are mainly characterized by plastic deformation and microcrack wear mechanism.Higher Ti target power can improve the wear resistance of TTOs.Erosion test results reveal that the impact crater,furrow,micro-cutting,brittle spalling,and crack formation are the main wear mechanisms of the TTOs samples under erosion conditions.展开更多
We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subse...We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.展开更多
Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys ar...Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.展开更多
Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase compositi...Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase composition and microstructure of the coatings were characterized using an X-ray diffractometer and a scanning electron microscope.The corrosion resistance of the coatings was as-sessed through electrochemical experiments and chloride ion corrosion tests.The results indicated that the coatings comprised both partially and fully melted regions,with spherical particles and pores present on the coating surfaces.The incorporation of CeO_(2)en-hanced the melting of the sprayed powder during the spraying process.When the CeO_(2)content was 0.2 wt.%,the melting of the sprayed powder was optimal.The porosity of the coating was minimized to 2.45%.CeO_(2)also positively influenced the grain refine-ment of the coating;at 0.2 wt.%CeO_(2),the grain size was at its minimum.The grain size of this coating was calculated to be 21.135 nm using the Scherrer formula.This coating demonstrated the best corrosion resistance,with a corrosion potential of-596.31 mV and a corrosion current density of 1.65×10^(-6)A/cm^(2),resulting in a weight loss of 0.0170 g due to chloride ion corrosion.展开更多
Building a superhydrophobic coating on a carbon steel substrate is an effective strategy for enhancing metal protection.A practical approach to producing a series of superhydrophobic Ni/SiO_(2)composite coatings(SSN)u...Building a superhydrophobic coating on a carbon steel substrate is an effective strategy for enhancing metal protection.A practical approach to producing a series of superhydrophobic Ni/SiO_(2)composite coatings(SSN)using one-step electrodeposition method is shown.The effect of processing parameters on surface structure and wettability was thoroughly explored,resulting in the identification of three typical surface morphologies.The prepared coating with petal-like structure(SSN-3)obtained under the optimum parameters exhibited the best water repellency,achieving a contact angle of 162.7°and a sliding angle of 4.1°.The droplet bouncing behavior on SSN coatings surface was studied,and the delayed icing time was recorded.Meanwhile,the mechanical stability and chemical corrosion resistance of SSN coatings were focused.The superhydrophobic SSN-3 coating with unique surface structure exhibited excellent reliability.The anticorrosion mechanism of SSN-3 coating was discussed,and its corrosion protection efficiency was up to 98.5%.The superior properties of the superhydrophobic SSN-3 coating make it suitable for diverse applications.展开更多
Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines pla...Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines plasma-enhanced non-equilibrium magnetron sputtering physical vapor deposition(PEUMS-PVD)and anodization to construct a self-healing three-dimensional Ti/Al-doped TiO_(2)nanotubes/Ti_(3)AlC_(2)coating on the surface of Cu substrates.This novel strategy enhances the corrosion resistance of copper substrates in marine environments,with corrosion current densities of up to 4.5643×10^(−8)A/cm^(2).Among them,the doping of nano-aluminum particles makes the coating self-healing.The mechanistic analysis of the corrosion behaviors during early immersion experiments was conducted using electrochemical noise,and revealed that during the initial stages of coating immersion,uniform corrosion predominates,with a minor occurrence of localized corrosion.展开更多
Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated ...Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated on the Mg alloy substrate,and then Sn_(3.0)Ag_(0.5)Cu(SAC 305)solder was utilized to facilitate the joining of AZ31 Mg/6061 Al through ultrasonic-assisted soldering.We investigated the impactof Al_(2)O_(3)nano sol content in the coating on microstructure evolution,IMCs formation,and mechanical properties.Results indicated that theNi-Al_(2)O_(3)composite coating effectively suppressed the Mg-Sn reaction,thereby preventing the formation of Mg_(2)Sn IMC and significantlyenhancing joint strength.In joints with a Ni-Al_(2)O_(3)composite coating containing 50 mL/L Al_(2)O_(3)nano sol,no Mg_(2)Sn IMC was detectedafter 50 min of holding at 260℃,achieving a maximum shear strength of approximately 67.2 MPa.Increasing the Al_(2)O_(3)concentrationfurther expanded the soldering process window.For the joint with Ni-Al_(2)O_(3)(100 mL/L Al_(2)O_(3)nano sol)composite coating held at 260℃for 70 min,the coating was dissolved to a thickness of about 5.8μm,but no Mg_(2)Sn IMC was observed.The Ni-based solid solution formednear the coating/solder interface was strengthened,leading to fractures occurring within the SAC solder,and the maximum shear strengthfurther increased to 73.9 MPa.The strengthening mechanism of the joints facilitated by using the Ni-Al_(2)O_(3)composite coating was revealedby comparing with pure Ni-assisted joints.Therefore,employing a Ni-Al_(2)O_(3)composite coating as a barrier layer represents a promisingstrategy for inhibiting IMC formation during the joining of dissimilar metals.展开更多
The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evo...The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.展开更多
To satisfy the demands of modern society for high-energy–density sulfide-based all-solid-state lithium batteries(ASSLBs),Ni-rich cathode materials have gained much attention for their high capacity and energy density...To satisfy the demands of modern society for high-energy–density sulfide-based all-solid-state lithium batteries(ASSLBs),Ni-rich cathode materials have gained much attention for their high capacity and energy density.However,their practical deployment is hindered by accelerated interface degradation and capacity decay originating from surface oxygen release and lattice oxygen activation during prolonged cycling.In this study,Ti_(x)NbB_((1−x))C_(2)was successfully coated on the surface of LiNi_(0.94)Co_(0.05)Mn_(0.01)O_(2).Density functional theory(DFT)calculations first elucidate a“point-to-point”anchoring mechanism where each surface oxygen atom coordinates with single species(Ti/Nb/B)offered by Ti_(x)NbB_((1−x))C_(2),which forms robust O–M bonds and sustain a stable interface structure.The electron energy loss spectroscopy(EELS)reveals the segregation of Ti/Nb toward subsurface layers during cycling,creating an optimized lattice oxygen coordination environment and suppressing oxygen activation.The dual oxygen stabilization mechanism dramatically improves the reversibility of phase transition and the structural stability of the Ni-rich cathode materials.Moreover,Ti_(x)NbB_((1−x))C_(2)as the protective layer decreases mechanical strain and suppresses the parasitic reactions.Consequently,the engineered cathode delivers 91%capacity retention after 1000 cycles at 0.3 C,suggesting excellent cycling stability.The research delivers a new design philosophy for the coating layer that can stabilize surface oxygen.Furthermore,the atomistic understanding of the structure–property relationship of the Ni-rich cathode materials provides valuable guidance for the future design of new cathode materials with superior structural stability in ASSLBs.展开更多
Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional co...Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.展开更多
Preparing multifunctional coatings with both anti-corrosion and anti-biofouling properties is crucial.Copper has been in the spotlight as an effective biocide,especially in the recent past concerning its impact on cau...Preparing multifunctional coatings with both anti-corrosion and anti-biofouling properties is crucial.Copper has been in the spotlight as an effective biocide,especially in the recent past concerning its impact on causing environmental hazards.Reducing the amount used and increasing its efficiency have become the focus of researchers.The hybridization of titanium dioxide nanoparticles(NPs)with copper metal-organic frameworks(MOFs)can significantly improve antimicrobial performance due to its photocatalytic properties.Composites(TiO_(2)-Cu-BTC)of titanium dioxide nanoparticles and copper 1,3,5-benzenetricarboxylate acid(Cu-BTC),obtained by three up-sampling methods,namely hydrothermal,mechanical stirring,and in-situ growth,were doped into epoxy resin(TiO_(2)-Cu-BTC/EP)to enhance its anticorrosion and antifouling properties.The loaded forms were determined by field emission scanning electron microscopy and confirmed using Fourier infrared spectroscopy and X-ray diffraction spectroscopy.The lethality of the composite coating against Escherichia coli(E.coli)increased by 12%after 3 h of exposure to light,and the impedance value increased by 1×1010Ω.The efficiency of the coating was greatly improved.展开更多
This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO proc...This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO process typically generates a porous oxide layer,which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate.To address this limitation,phenopyridine(PHEN)and 2-methylimidazole(2-IMD)were incorporated into the PEO surface to form a robust organic layer on the Mg alloy.Potassium hydroxide(KOH)was used to adjust the pH,improving the interaction and solubility between the organic molecules and the PEO coating.The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity.The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance,with the lowest corrosion current density(I_(corr))of 1.92×10^(-10) A/cm^(2),a high corrosion potential(E_(corr)),and the highest top layer resistance(R_(top))of 2.57×10^(6)Ω·cm^(2),indicating excellent barrier properties.Additionally,the coating achieved complete(100%)degradation of methylene blue(MB)within 30 min under visible light.Density Functional Theory(DFT)calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN,2-IMD,and the PEO layer on the Mg alloy and MB dye.These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.展开更多
Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The resul...Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The results indicate that the composite coatings primarily comprised Ti_(2)AlC,α_(2)-Ti_(3)Al,γ-TiAl,TiC,and W phases.A gradual increase in the relative intensity of the diffraction peaks of Ti_(2)AlC,α_(2)-Ti_(3)Al,and TiC appeared with the increase of specific energy.When the specific energy was 116.7 J/mm^(2),the Ti−Al/WC coated alloy achieved a maximum micro-hardness of HV0.2766.3,which represented an increase of 1.96 times compared with TC21 alloy,and the minimum wear rate decreased dramatically.Much improvement in tribological properties was attained through the fine-grained strengthening of the(α_(2)+γ)matrix and the dispersion strengthening of self-lubricating Ti_(2)AlC and intertwining TiC.This study provides valuable insights for the development of high-performance Ti−Al composite coatings.展开更多
Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in m...Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.展开更多
The influence of cathodic pulse parameters was evaluated on plasma electrolytic oxidation(PEO)coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate(PTO)using pulsed...The influence of cathodic pulse parameters was evaluated on plasma electrolytic oxidation(PEO)coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate(PTO)using pulsed bipolar waveforms with various cathodic duty cycles and cathodic current densities.The coatings were characterized by SEM,EDS,and XRD.EIS was applied to investigate the electrochemical properties.It was observed that the increase of cathodic duty cycle and cathodic current density from 20%and 6 A/dm^(2) to 40%and 12 A/dm^(2) enhances the growth rate of the inner layer from 0.22 to 0.75μm/min.Adding PTO into the bath showed a fortifying effect on influence of the cathodic pulse and the mentioned change of cathodic pulse parameters,resulting in an increase of the inner layer growth rate from 0.25 to 1.10μm/min.Based on EDS analysis,Si and Ti were incorporated dominantly in the upper parts of the coatings.XRD technique merely detectedγ-Al_(2)O_(3),and there were no detectable peaks related to Ti and Si compounds.However,the EIS results confirmed that the incorporation of Ti^(4+)into alumina changed the electronic properties of the coating.The coatings obtained from the bath containing PTO using the bipolar waveforms with a cathodic duty cycle of 40%and current density values higher than 6 A/dm^(2) showed highly appropriate electrochemical behavior during 240 d of immersion due to an efficient repairing mechanism.Regarding the effects of studied parameters on the coating properties,the roles of cathodic pulse parameters and PTO in the PEO process were highlighted.展开更多
The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by usin...The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.展开更多
High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3...High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3)-coated PF(Y_(2)O_(3)/PF)powder was firstly sprayed onto the substrate,forming a transition layer,and then the spherical Y_(2)O_(3) powder and Y_(2)O_(3)/PF powder were alternately deposited to form the composite alternating coating.Results show that the alternating coating is mainly composed of deposited Y_(2)O_(3)/PF powder.The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa,and shear strength reaches 24.30 MPa.Additionally,the heat transfer effect caused by external Y_(2)O_(3) particles gradually softens and even melts PF,thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process.In the meantime,the unmelted Y_(2)O_(3) powder results in the shot peening effect,which washes out and eliminates the powder particles with inferior deposition effect,ultimately improving the physical and chemical properties of the alternating coating.展开更多
To improve the oxidation resistance of carbon/carbon composites,ZrB2-MoSi2/SiC coating on the carbon/carbon substrate was prepared.The inner coating of SiC was prepared by pack cementation and the outer coating of ZrB...To improve the oxidation resistance of carbon/carbon composites,ZrB2-MoSi2/SiC coating on the carbon/carbon substrate was prepared.The inner coating of SiC was prepared by pack cementation and the outer coating of ZrB2-MoSi2 was prepared by slurry painting.The phase compositions and microstructures of the coating were characterized by XRD and SEM,respectively.The preparation and the high temperature oxidation property of the coated composites were investigated.The results show that the outer coating of carbon/carbon composites is composed of ZrB2,MoSi2 and SiC phases.The mass losses of the ZrB2-MoSi2/SiC coated samples with SiC nano-whiskers after 30 h and 10 h of oxidation at 1 273 K and 1 773 K were,respectively,5.3% and 3.0%.The ZrB2-MoSi2/SiC coated samples exhibit self-sealing performance and good oxidation resistance at high temperature.展开更多
To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack ceme...To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.展开更多
文摘To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.
文摘To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth structure,microstructure,and tribological properties of TTOs with Ti target power was studied.After the erosion test,the variation of erosion damage behavior of TTOs with mechanical properties under different erosion conditions was further studied.The results show that the TTOs eliminate the roughness,voids,and defects in the material due to the mobility of the adsorbed atoms during the growth process,and a flat and dense smooth surface is obtained.Tribological tests show that the TTOs are mainly characterized by plastic deformation and microcrack wear mechanism.Higher Ti target power can improve the wear resistance of TTOs.Erosion test results reveal that the impact crater,furrow,micro-cutting,brittle spalling,and crack formation are the main wear mechanisms of the TTOs samples under erosion conditions.
基金Funded by Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100006722022)。
文摘We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.
基金supported by the National Natural Science Foundation of China(No.52374401 and 52404409)the Key R&D Plan of Shaanxi Province(Nos.2024QCYKXJ-116 and 2023JBGS-14)+3 种基金the Scientific and Technological Innovation Team Project of Shaanxi Innovation Capability Support Plan(No.2022TD-30)Xi’an Science and Technology Plan Project(No.2023JHGXRC-0020)the“Young Talent Support Project”of China Association for Science and Technology of China.The Natural Science Foundation of Shaanxi Provincial(No.2024JC-YBQN-0367)China Postdoctoral Science Foundation(2024MD753961).
文摘Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.
基金supported by the National Natural Science Foundation of China(Grant No.52375387).
文摘Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase composition and microstructure of the coatings were characterized using an X-ray diffractometer and a scanning electron microscope.The corrosion resistance of the coatings was as-sessed through electrochemical experiments and chloride ion corrosion tests.The results indicated that the coatings comprised both partially and fully melted regions,with spherical particles and pores present on the coating surfaces.The incorporation of CeO_(2)en-hanced the melting of the sprayed powder during the spraying process.When the CeO_(2)content was 0.2 wt.%,the melting of the sprayed powder was optimal.The porosity of the coating was minimized to 2.45%.CeO_(2)also positively influenced the grain refine-ment of the coating;at 0.2 wt.%CeO_(2),the grain size was at its minimum.The grain size of this coating was calculated to be 21.135 nm using the Scherrer formula.This coating demonstrated the best corrosion resistance,with a corrosion potential of-596.31 mV and a corrosion current density of 1.65×10^(-6)A/cm^(2),resulting in a weight loss of 0.0170 g due to chloride ion corrosion.
基金the Natural Science Foundation of Chongqing of China(Nos.CSTB2024NSCQ-MSX1013 and cstc2021jcyj-msxmX1139)the Science and Technology Research Program of Chongqing Education Commission(Nos.KJZD-K202304502,KJQN202201214,KJQN202001243 and KJZD-M202301201)the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan province(No.2024CL05).
文摘Building a superhydrophobic coating on a carbon steel substrate is an effective strategy for enhancing metal protection.A practical approach to producing a series of superhydrophobic Ni/SiO_(2)composite coatings(SSN)using one-step electrodeposition method is shown.The effect of processing parameters on surface structure and wettability was thoroughly explored,resulting in the identification of three typical surface morphologies.The prepared coating with petal-like structure(SSN-3)obtained under the optimum parameters exhibited the best water repellency,achieving a contact angle of 162.7°and a sliding angle of 4.1°.The droplet bouncing behavior on SSN coatings surface was studied,and the delayed icing time was recorded.Meanwhile,the mechanical stability and chemical corrosion resistance of SSN coatings were focused.The superhydrophobic SSN-3 coating with unique surface structure exhibited excellent reliability.The anticorrosion mechanism of SSN-3 coating was discussed,and its corrosion protection efficiency was up to 98.5%.The superior properties of the superhydrophobic SSN-3 coating make it suitable for diverse applications.
基金Projects(42106051,42006046,U2106206) supported by the National Natural Science Foundation of ChinaProject(22373501D) supported by Hebei Provincial Key R&D Program,China。
文摘Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines plasma-enhanced non-equilibrium magnetron sputtering physical vapor deposition(PEUMS-PVD)and anodization to construct a self-healing three-dimensional Ti/Al-doped TiO_(2)nanotubes/Ti_(3)AlC_(2)coating on the surface of Cu substrates.This novel strategy enhances the corrosion resistance of copper substrates in marine environments,with corrosion current densities of up to 4.5643×10^(−8)A/cm^(2).Among them,the doping of nano-aluminum particles makes the coating self-healing.The mechanistic analysis of the corrosion behaviors during early immersion experiments was conducted using electrochemical noise,and revealed that during the initial stages of coating immersion,uniform corrosion predominates,with a minor occurrence of localized corrosion.
基金support from the National Natural Science Foundation of China(grant numbers 52275385 and U2167216).
文摘Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated on the Mg alloy substrate,and then Sn_(3.0)Ag_(0.5)Cu(SAC 305)solder was utilized to facilitate the joining of AZ31 Mg/6061 Al through ultrasonic-assisted soldering.We investigated the impactof Al_(2)O_(3)nano sol content in the coating on microstructure evolution,IMCs formation,and mechanical properties.Results indicated that theNi-Al_(2)O_(3)composite coating effectively suppressed the Mg-Sn reaction,thereby preventing the formation of Mg_(2)Sn IMC and significantlyenhancing joint strength.In joints with a Ni-Al_(2)O_(3)composite coating containing 50 mL/L Al_(2)O_(3)nano sol,no Mg_(2)Sn IMC was detectedafter 50 min of holding at 260℃,achieving a maximum shear strength of approximately 67.2 MPa.Increasing the Al_(2)O_(3)concentrationfurther expanded the soldering process window.For the joint with Ni-Al_(2)O_(3)(100 mL/L Al_(2)O_(3)nano sol)composite coating held at 260℃for 70 min,the coating was dissolved to a thickness of about 5.8μm,but no Mg_(2)Sn IMC was observed.The Ni-based solid solution formednear the coating/solder interface was strengthened,leading to fractures occurring within the SAC solder,and the maximum shear strengthfurther increased to 73.9 MPa.The strengthening mechanism of the joints facilitated by using the Ni-Al_(2)O_(3)composite coating was revealedby comparing with pure Ni-assisted joints.Therefore,employing a Ni-Al_(2)O_(3)composite coating as a barrier layer represents a promisingstrategy for inhibiting IMC formation during the joining of dissimilar metals.
基金supported by the National Key Research and Development Programme(2023YFB3408200)the National Nature Science Foundation of China(52201076 and 52471077)+2 种基金the Guangdong Provincial Key R&D Programme(2023B0909020002)the Guangdong Basic and Applied Basic Research Foundation(2021A1515111065,2021B1515120014 and 2022A1515010934)the Fundamental Research Funds for the Central Universities(21623216 and 11623216).
文摘The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.
基金supported by the National Natural Science Foundation of China(21203008,21975025,12274025,22372008,and 22179007)Hainan Province Science and Technology Special Fund(ZDYF2021SHFZ232 and ZDYF2023GXJS022)Hainan Province Postdoctoral Science Foundation(300333)。
文摘To satisfy the demands of modern society for high-energy–density sulfide-based all-solid-state lithium batteries(ASSLBs),Ni-rich cathode materials have gained much attention for their high capacity and energy density.However,their practical deployment is hindered by accelerated interface degradation and capacity decay originating from surface oxygen release and lattice oxygen activation during prolonged cycling.In this study,Ti_(x)NbB_((1−x))C_(2)was successfully coated on the surface of LiNi_(0.94)Co_(0.05)Mn_(0.01)O_(2).Density functional theory(DFT)calculations first elucidate a“point-to-point”anchoring mechanism where each surface oxygen atom coordinates with single species(Ti/Nb/B)offered by Ti_(x)NbB_((1−x))C_(2),which forms robust O–M bonds and sustain a stable interface structure.The electron energy loss spectroscopy(EELS)reveals the segregation of Ti/Nb toward subsurface layers during cycling,creating an optimized lattice oxygen coordination environment and suppressing oxygen activation.The dual oxygen stabilization mechanism dramatically improves the reversibility of phase transition and the structural stability of the Ni-rich cathode materials.Moreover,Ti_(x)NbB_((1−x))C_(2)as the protective layer decreases mechanical strain and suppresses the parasitic reactions.Consequently,the engineered cathode delivers 91%capacity retention after 1000 cycles at 0.3 C,suggesting excellent cycling stability.The research delivers a new design philosophy for the coating layer that can stabilize surface oxygen.Furthermore,the atomistic understanding of the structure–property relationship of the Ni-rich cathode materials provides valuable guidance for the future design of new cathode materials with superior structural stability in ASSLBs.
文摘Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.
基金Project(52073311) supported by the National Natural Science Foundation of ChinaProject(2023A0505010011) supported by the Guangdong-Hong Kong-Macao Joint Innovation Field Research Foundation,ChinaProject(2021A1515012281) supported by the Guangdong Basic and Applied Basic Research Foundation,China。
文摘Preparing multifunctional coatings with both anti-corrosion and anti-biofouling properties is crucial.Copper has been in the spotlight as an effective biocide,especially in the recent past concerning its impact on causing environmental hazards.Reducing the amount used and increasing its efficiency have become the focus of researchers.The hybridization of titanium dioxide nanoparticles(NPs)with copper metal-organic frameworks(MOFs)can significantly improve antimicrobial performance due to its photocatalytic properties.Composites(TiO_(2)-Cu-BTC)of titanium dioxide nanoparticles and copper 1,3,5-benzenetricarboxylate acid(Cu-BTC),obtained by three up-sampling methods,namely hydrothermal,mechanical stirring,and in-situ growth,were doped into epoxy resin(TiO_(2)-Cu-BTC/EP)to enhance its anticorrosion and antifouling properties.The loaded forms were determined by field emission scanning electron microscopy and confirmed using Fourier infrared spectroscopy and X-ray diffraction spectroscopy.The lethality of the composite coating against Escherichia coli(E.coli)increased by 12%after 3 h of exposure to light,and the impedance value increased by 1×1010Ω.The efficiency of the coating was greatly improved.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO process typically generates a porous oxide layer,which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate.To address this limitation,phenopyridine(PHEN)and 2-methylimidazole(2-IMD)were incorporated into the PEO surface to form a robust organic layer on the Mg alloy.Potassium hydroxide(KOH)was used to adjust the pH,improving the interaction and solubility between the organic molecules and the PEO coating.The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity.The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance,with the lowest corrosion current density(I_(corr))of 1.92×10^(-10) A/cm^(2),a high corrosion potential(E_(corr)),and the highest top layer resistance(R_(top))of 2.57×10^(6)Ω·cm^(2),indicating excellent barrier properties.Additionally,the coating achieved complete(100%)degradation of methylene blue(MB)within 30 min under visible light.Density Functional Theory(DFT)calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN,2-IMD,and the PEO layer on the Mg alloy and MB dye.These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.
基金supported by the Guangxi Science and Technology Program,China(Nos.Guike AD23026170,Guike AD23026116)the Guangxi Key Laboratory of Manufacturing System and Advanced Manufacturing Technology,China(No.22-35-4-S019)+3 种基金the Research Basic Ability Enhancement Program for Young and Middle-aged Teachers of Guangxi,China(No.2023KY0202)China Postdoctoral Science Foundation(No.2024M753642)the Guilin Science and Technology Development Program(Project),China(No.20220124-10)the Innovation Project of GUET Graduate Education,China(No.2024YCXS008).
文摘Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The results indicate that the composite coatings primarily comprised Ti_(2)AlC,α_(2)-Ti_(3)Al,γ-TiAl,TiC,and W phases.A gradual increase in the relative intensity of the diffraction peaks of Ti_(2)AlC,α_(2)-Ti_(3)Al,and TiC appeared with the increase of specific energy.When the specific energy was 116.7 J/mm^(2),the Ti−Al/WC coated alloy achieved a maximum micro-hardness of HV0.2766.3,which represented an increase of 1.96 times compared with TC21 alloy,and the minimum wear rate decreased dramatically.Much improvement in tribological properties was attained through the fine-grained strengthening of the(α_(2)+γ)matrix and the dispersion strengthening of self-lubricating Ti_(2)AlC and intertwining TiC.This study provides valuable insights for the development of high-performance Ti−Al composite coatings.
基金support from the National Natural Science Foundation of China(2207213641672033)+2 种基金the research grants from Engineering Research Center of Non-metallic Minerals of Zhejiang Province(ZD2023K01)the projects from Qing Yang Institute for Industrial Minerals(KYYHX-20220336KYY-HX-20170557).
文摘Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.
文摘The influence of cathodic pulse parameters was evaluated on plasma electrolytic oxidation(PEO)coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate(PTO)using pulsed bipolar waveforms with various cathodic duty cycles and cathodic current densities.The coatings were characterized by SEM,EDS,and XRD.EIS was applied to investigate the electrochemical properties.It was observed that the increase of cathodic duty cycle and cathodic current density from 20%and 6 A/dm^(2) to 40%and 12 A/dm^(2) enhances the growth rate of the inner layer from 0.22 to 0.75μm/min.Adding PTO into the bath showed a fortifying effect on influence of the cathodic pulse and the mentioned change of cathodic pulse parameters,resulting in an increase of the inner layer growth rate from 0.25 to 1.10μm/min.Based on EDS analysis,Si and Ti were incorporated dominantly in the upper parts of the coatings.XRD technique merely detectedγ-Al_(2)O_(3),and there were no detectable peaks related to Ti and Si compounds.However,the EIS results confirmed that the incorporation of Ti^(4+)into alumina changed the electronic properties of the coating.The coatings obtained from the bath containing PTO using the bipolar waveforms with a cathodic duty cycle of 40%and current density values higher than 6 A/dm^(2) showed highly appropriate electrochemical behavior during 240 d of immersion due to an efficient repairing mechanism.Regarding the effects of studied parameters on the coating properties,the roles of cathodic pulse parameters and PTO in the PEO process were highlighted.
基金Fundamental Research Funds for Central Universities Project (No. 1CX05021A)Shandong Provincial Key R&D Plan Project (No. 2GHY15108)Shandong Postdoctoral Innovation Project and Qingdao Postdoctoral Applied Research Project。
文摘The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.
基金National Natural Science Foundation of China(52130509,52275211,52075542)Supported by 145 Project+1 种基金Science and Technology New Star Project of Shaanxi Innovation Capability Support Program(2021KJXX-38)China Postdoctoral Science Foundation(2021M693883)。
文摘High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3)-coated PF(Y_(2)O_(3)/PF)powder was firstly sprayed onto the substrate,forming a transition layer,and then the spherical Y_(2)O_(3) powder and Y_(2)O_(3)/PF powder were alternately deposited to form the composite alternating coating.Results show that the alternating coating is mainly composed of deposited Y_(2)O_(3)/PF powder.The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa,and shear strength reaches 24.30 MPa.Additionally,the heat transfer effect caused by external Y_(2)O_(3) particles gradually softens and even melts PF,thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process.In the meantime,the unmelted Y_(2)O_(3) powder results in the shot peening effect,which washes out and eliminates the powder particles with inferior deposition effect,ultimately improving the physical and chemical properties of the alternating coating.
基金Project(50721003) supported by the Innovation Community Foundation of National Natural Science of ChinaProject(2011CB605805) supported by the National Basic Research Program of China
文摘To improve the oxidation resistance of carbon/carbon composites,ZrB2-MoSi2/SiC coating on the carbon/carbon substrate was prepared.The inner coating of SiC was prepared by pack cementation and the outer coating of ZrB2-MoSi2 was prepared by slurry painting.The phase compositions and microstructures of the coating were characterized by XRD and SEM,respectively.The preparation and the high temperature oxidation property of the coated composites were investigated.The results show that the outer coating of carbon/carbon composites is composed of ZrB2,MoSi2 and SiC phases.The mass losses of the ZrB2-MoSi2/SiC coated samples with SiC nano-whiskers after 30 h and 10 h of oxidation at 1 273 K and 1 773 K were,respectively,5.3% and 3.0%.The ZrB2-MoSi2/SiC coated samples exhibit self-sealing performance and good oxidation resistance at high temperature.
基金Projects(51221001,50972120)supported by the National Natural Science Foundation of ChinaProject(73-QP-2010)supported by the Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.
