A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate w...A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate was realized by ion-exchange reaction.The structure,morphology and composition of as-prepared LDH film were investigated by X-ray diffractometer,field-emission scanning electronic microscope and energy dispersive spectrometry.Results indicated that a uniform and compact LDH film was formed and the intercalation of Ce^(3+)and vanadate would change the crystal structure of LDHs.The results of the potentiodynamic polarization,electrochemical impedance spectra,hydrogen evolution and corrosion weight loss tests showed the Ce^(3+)and vanadate anions significantly improve the impedance of LDH film,and the active double-doped LDH film could effectively protect the magnesium substrate from corrosion.展开更多
Highly oriented Mg-Al layered double hydroxide(LDHs)films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth method.The characteristics of the films were investigated...Highly oriented Mg-Al layered double hydroxide(LDHs)films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth method.The characteristics of the films were investigated by optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),and electrochemical,immersion and hydrogen evolution tests.The corrosion protection performance ranked the LDHs films as the increasing series:CS-LDHs(as-cast sample with LDHs)<AE-LDHs(asymmetric extrusion sample with LDHs)<SE-LDHs(symmetric extrusion sample with LDHs)<RS-LDHs(rolled sample with LDHs).A thicker and more compact LDH conversion coating was formed on the RS sample,and had the best corrosion protection performance.展开更多
Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is ...Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is a key.This study aims to address such issues through anodizing Ti-10V-2Fe-3Al alloy in malic acid,followed by a post-sealing treatment with Mg-Al layered double hydroxides(LDHs).The characteristics of the samples were investigated using scanning electron microscopy(SEM),atomic force microscopy(AFM),glow discharge optical emission spectroscopy(GDOES),X-ray diffraction(XRD)and energy-dispersive X-ray spectroscopy(EDS).SEM micrographs reveals that the anodic coating had a surface full of bulges and cracks,and was almost sealed by the following LDHs treatment.XRD pattern indicate that the anodic coating was mainly consisted of amorphous TiO2 with a small fraction of anatase,but its crystallization degree was increased through the post-sealing.Moreover,electrochemical and tribological measurements demonstrate that corrosion current density was 2.8×10-6,2.0×10-7,5.9×10-9A cm-2,and wear rate was 1.45×10-3,1.30×10-4 and 6.90×10-5 mm3 N-1 m-1 for respective bare Ti-10V-2Fe-3Al alloy substrate,anodized specimens without and with the LDHs post treatment.Finally,a plausible wear mechanism was proposed.展开更多
A thick composite anodic oxide film was fabricated in an environmentally friendly malic acid electrolyte containing Poly Tetra Fluoro Ethylene(PTFE)nanoparticles on Ti-10V-2Fe-3Al alloys.The influence of pulse frequen...A thick composite anodic oxide film was fabricated in an environmentally friendly malic acid electrolyte containing Poly Tetra Fluoro Ethylene(PTFE)nanoparticles on Ti-10V-2Fe-3Al alloys.The influence of pulse frequency on the morphology,microstructure and composition of composite anodic oxide films containing PTFE nanoparticles was investigated using Field Emission Scanning Electron Microscopy(FE-SEM)equipped with Energy Dispersive Spectroscopy(EDS),Atomic Force Microscopy(AFM)and Raman spectroscopy.The tribological properties in terms of the friction coefficient,wear loss and morphology of worn surfaces were measured by ball-ondisc tests.The electrochemical property was evaluated by potentiodynamic polarization.The results indicated that the titanium dioxide of composite anodic oxide films transformed from anatase to rutile with the change of pulse frequency,which could result from the electrochemical dynamic equilibrium.The combination of PTFE nanoparticles and malic acid electrolyte molecules can influence the energy fluctuation of electrochemical equilibrium and formation of composite anodic oxide films.Moreover,composite anodic oxide films fabricated under the condition of 1.0–2.0 Hz exhibited the best wear resistance and corrosion property.The schematic diagram of the film formation and PTFE nanoparticles spreading process under different frequencies was elucidated.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51971040)the Graduate Research and Innovation Foundation of Chongqing,China(No.CYS19002)+4 种基金the National Natural Science Foundation of China(Nos.51701029 and 51531002)the National Key Research and Development Program of China(No.2016YFB0301100)the China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)the Fundamental Research Funds for the Central Universities(No.2018CDGFCL005)。
文摘A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate was realized by ion-exchange reaction.The structure,morphology and composition of as-prepared LDH film were investigated by X-ray diffractometer,field-emission scanning electronic microscope and energy dispersive spectrometry.Results indicated that a uniform and compact LDH film was formed and the intercalation of Ce^(3+)and vanadate would change the crystal structure of LDHs.The results of the potentiodynamic polarization,electrochemical impedance spectra,hydrogen evolution and corrosion weight loss tests showed the Ce^(3+)and vanadate anions significantly improve the impedance of LDH film,and the active double-doped LDH film could effectively protect the magnesium substrate from corrosion.
基金financially supported by the National Natural Science Foundation of China(Nos.51971040,51701029 and 51531002)the National Key Research and Development Program of China(No.2016YFB0301100)+2 种基金the China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)the Fundamental Research Funds for the Central Universities(No.2018CDGFCL005)。
文摘Highly oriented Mg-Al layered double hydroxide(LDHs)films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth method.The characteristics of the films were investigated by optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),and electrochemical,immersion and hydrogen evolution tests.The corrosion protection performance ranked the LDHs films as the increasing series:CS-LDHs(as-cast sample with LDHs)<AE-LDHs(asymmetric extrusion sample with LDHs)<SE-LDHs(symmetric extrusion sample with LDHs)<RS-LDHs(rolled sample with LDHs).A thicker and more compact LDH conversion coating was formed on the RS sample,and had the best corrosion protection performance.
基金supported financially by the National Natural Science Foundation of China(Nos.51971040,51701029 and 51531002)the National Key Research and Development Program of China(No.2016YFB0301100)+3 种基金the Chongqing Research Program of Basic Research and Frontier Technology(No.cstc2016jcyjA0388)the China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)the Fundamental Research Funds for the Central Universities(No.2018CDGFCL005).
文摘Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is a key.This study aims to address such issues through anodizing Ti-10V-2Fe-3Al alloy in malic acid,followed by a post-sealing treatment with Mg-Al layered double hydroxides(LDHs).The characteristics of the samples were investigated using scanning electron microscopy(SEM),atomic force microscopy(AFM),glow discharge optical emission spectroscopy(GDOES),X-ray diffraction(XRD)and energy-dispersive X-ray spectroscopy(EDS).SEM micrographs reveals that the anodic coating had a surface full of bulges and cracks,and was almost sealed by the following LDHs treatment.XRD pattern indicate that the anodic coating was mainly consisted of amorphous TiO2 with a small fraction of anatase,but its crystallization degree was increased through the post-sealing.Moreover,electrochemical and tribological measurements demonstrate that corrosion current density was 2.8×10-6,2.0×10-7,5.9×10-9A cm-2,and wear rate was 1.45×10-3,1.30×10-4 and 6.90×10-5 mm3 N-1 m-1 for respective bare Ti-10V-2Fe-3Al alloy substrate,anodized specimens without and with the LDHs post treatment.Finally,a plausible wear mechanism was proposed.
基金co-supported by the National Natural Science Foundation of China(Nos.51971040 and 51971044)the Fundamental Research Funds for the Central Universities,China(2020CDJQY-A007)+1 种基金China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)。
文摘A thick composite anodic oxide film was fabricated in an environmentally friendly malic acid electrolyte containing Poly Tetra Fluoro Ethylene(PTFE)nanoparticles on Ti-10V-2Fe-3Al alloys.The influence of pulse frequency on the morphology,microstructure and composition of composite anodic oxide films containing PTFE nanoparticles was investigated using Field Emission Scanning Electron Microscopy(FE-SEM)equipped with Energy Dispersive Spectroscopy(EDS),Atomic Force Microscopy(AFM)and Raman spectroscopy.The tribological properties in terms of the friction coefficient,wear loss and morphology of worn surfaces were measured by ball-ondisc tests.The electrochemical property was evaluated by potentiodynamic polarization.The results indicated that the titanium dioxide of composite anodic oxide films transformed from anatase to rutile with the change of pulse frequency,which could result from the electrochemical dynamic equilibrium.The combination of PTFE nanoparticles and malic acid electrolyte molecules can influence the energy fluctuation of electrochemical equilibrium and formation of composite anodic oxide films.Moreover,composite anodic oxide films fabricated under the condition of 1.0–2.0 Hz exhibited the best wear resistance and corrosion property.The schematic diagram of the film formation and PTFE nanoparticles spreading process under different frequencies was elucidated.
