To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.F...To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.Four reduction peaks were observed in the cyclic voltammogram of the EC-AlCl3-TaCl5 ionic liquid.The reduction peaks at-0.55,-0.72,and-1.12 V(vs Al)were related to the reduction of Ta(Ⅴ)to tantalum metal by three stages including the formation of Ta(Ⅳ)and Ta(Ⅲ)complex ions.The reduction of Ta(Ⅲ)to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10^-7 cm^2/s at 323 K,and the diffusion activation energy was 77 k J/mol.Moreover,the cathode products at 323 K were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray photoelectron spectroscopy.The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at-0.8 V for 2 h.展开更多
Zinc chloride(ZnCl_(2))was dissolved in the 1,3-dimethyl-2-imidazolinone(DMI)solvent,and the metallic zinc coatings were obtained by electrodeposition in room-temperature ambient air.The conductivity(σ),viscosity(η)...Zinc chloride(ZnCl_(2))was dissolved in the 1,3-dimethyl-2-imidazolinone(DMI)solvent,and the metallic zinc coatings were obtained by electrodeposition in room-temperature ambient air.The conductivity(σ),viscosity(η),and density(ρ)of the DMI−ZnCl_(2)solvated ionic liquid at various temperatures(T)were measured and fitted.Furthermore,cyclic voltammetry was used to study the electrochemical behavior of Zn(II)in the DMI−ZnCl_(2)solvated ionic liquid,indicating that the reduction of Zn(II)on the tungsten electrode was a one-step two-electron transfer irreversible process.XRD and SEM−EDS analysis of the cathode product confirmed that the deposited coating was metallic zinc.Finally,the effects of deposition potential,temperature and duration on the morphology of zinc coatings were investigated.The results showed that a dense and uniform zinc coating was obtained by potentiostatic electrodeposition at−2 V(vs Pt)and 353 K for 1 h.展开更多
The anodic behaviour of pre-oxidised and non-oxidised Cu-Al-based anodes(Cu-10Al and Cu-9.8Al-2Mn)in KF-AlF_(3)-Al_(2)O_(3)melts was studied through galvanostatic and potentiodynamic polarization techniques.The alloy ...The anodic behaviour of pre-oxidised and non-oxidised Cu-Al-based anodes(Cu-10Al and Cu-9.8Al-2Mn)in KF-AlF_(3)-Al_(2)O_(3)melts was studied through galvanostatic and potentiodynamic polarization techniques.The alloy compositions were oxidised for a short-term(8 h)at 700℃,followed by galvanostatic polarization for 1 h at 800℃with an applied current density of 0.4 A/cm^(2).The potentiodynamic curves were recorded with a sweep rate of 0.01 V/s.XRD analysis was conducted on frozen melt samples collected on the surface of the anode,and SEM observation was performed on the anode after the experiment to study the phases of the scales formed on the alloys.All the anode materials had a steady potential between 2.30 and 2.50 V(vs Al/AlF_(3)).The corrosion rates of the anodes were calculated from the data acquired through potentiodynamic polarization.It was seen that pre-oxidised anodes possess a low corrosion rate compared to those without pre-oxidation treatment.展开更多
基金Projects(N182503033N172502003)supported by the Fundamental Research Funds for the Central Universities,China+1 种基金Project(2018M640258)supported by Postdoctoral Research Foundation of ChinaProject(GUIKE AA18118030)supported by Guangxi Innovation-driven Development Program,China。
文摘To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.Four reduction peaks were observed in the cyclic voltammogram of the EC-AlCl3-TaCl5 ionic liquid.The reduction peaks at-0.55,-0.72,and-1.12 V(vs Al)were related to the reduction of Ta(Ⅴ)to tantalum metal by three stages including the formation of Ta(Ⅳ)and Ta(Ⅲ)complex ions.The reduction of Ta(Ⅲ)to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10^-7 cm^2/s at 323 K,and the diffusion activation energy was 77 k J/mol.Moreover,the cathode products at 323 K were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray photoelectron spectroscopy.The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at-0.8 V for 2 h.
基金The authors are grateful for the financial supports from the Fundamental Research Funds for the Central Universities,China(N182503033,N172502003)Postdoctoral Research Foundation of China(2018M640258)+1 种基金the National Natural Science Foundation of China(51804070)Guangxi Innovation-driven Development Program,China(GUIKE AA18118030).
文摘Zinc chloride(ZnCl_(2))was dissolved in the 1,3-dimethyl-2-imidazolinone(DMI)solvent,and the metallic zinc coatings were obtained by electrodeposition in room-temperature ambient air.The conductivity(σ),viscosity(η),and density(ρ)of the DMI−ZnCl_(2)solvated ionic liquid at various temperatures(T)were measured and fitted.Furthermore,cyclic voltammetry was used to study the electrochemical behavior of Zn(II)in the DMI−ZnCl_(2)solvated ionic liquid,indicating that the reduction of Zn(II)on the tungsten electrode was a one-step two-electron transfer irreversible process.XRD and SEM−EDS analysis of the cathode product confirmed that the deposited coating was metallic zinc.Finally,the effects of deposition potential,temperature and duration on the morphology of zinc coatings were investigated.The results showed that a dense and uniform zinc coating was obtained by potentiostatic electrodeposition at−2 V(vs Pt)and 353 K for 1 h.
文摘The anodic behaviour of pre-oxidised and non-oxidised Cu-Al-based anodes(Cu-10Al and Cu-9.8Al-2Mn)in KF-AlF_(3)-Al_(2)O_(3)melts was studied through galvanostatic and potentiodynamic polarization techniques.The alloy compositions were oxidised for a short-term(8 h)at 700℃,followed by galvanostatic polarization for 1 h at 800℃with an applied current density of 0.4 A/cm^(2).The potentiodynamic curves were recorded with a sweep rate of 0.01 V/s.XRD analysis was conducted on frozen melt samples collected on the surface of the anode,and SEM observation was performed on the anode after the experiment to study the phases of the scales formed on the alloys.All the anode materials had a steady potential between 2.30 and 2.50 V(vs Al/AlF_(3)).The corrosion rates of the anodes were calculated from the data acquired through potentiodynamic polarization.It was seen that pre-oxidised anodes possess a low corrosion rate compared to those without pre-oxidation treatment.