Electrochemical impendence spectroscopy （EIS） is applied to investigate the dissolution behavior of Al-Zn alloys in 3% NaCl solution at different polarization potentials. A new reaction model is proposed, and the ac...Electrochemical impendence spectroscopy （EIS） is applied to investigate the dissolution behavior of Al-Zn alloys in 3% NaCl solution at different polarization potentials. A new reaction model is proposed, and the activation mechanism of zinc in Al-Zn alloys is achieved. There are three intermediates in the dissolution process： Znad^＋, Znad^2＋ and Alad^＋, ,of which only Zni can activate Al-Zn alloys. Most Znnd^＋ is produced by β-phase,and the alloys with 2. 3% - 3. 8% （wt） Zn dissolve rapidly. The Al-Zn alloys of heart-shaped EIS are active in 3% NaCl solution, thus EIS characteristic can be used to distinguish the activa-tion of Al-Zn alloys.展开更多
采用阳极氧化法制备了Al_2O_3绝缘材料,并制备了以Al_2O_3为绝缘层的并五苯薄膜晶体管器件(OTFT)。Al_2O_3绝缘层经过10 min 350℃氢热处理后,OTFT迁移率比未经氢热处理的增大近20倍,且阈值电压降到了-7 V。Al_2O_3膜MIS结构电容—电压(...采用阳极氧化法制备了Al_2O_3绝缘材料,并制备了以Al_2O_3为绝缘层的并五苯薄膜晶体管器件(OTFT)。Al_2O_3绝缘层经过10 min 350℃氢热处理后,OTFT迁移率比未经氢热处理的增大近20倍,且阈值电压降到了-7 V。Al_2O_3膜MIS结构电容—电压(C–V)特性的平带电压平移量数据表明,Al_2O_3膜经过热处理后,并五苯半导体与Al_2O_3绝缘体界面处以及绝缘体内缺陷态密度显著地降低,Al_2O_3绝缘层和并五苯半导体层之间的接触得到改善,这使得经热处理Al_2O_3膜的OTFT器件性能得到显著的改善。展开更多
The α-PbO2 deposition layers were prepared on the surface of A1/Pb substrates by constant current electrosynthesis from an alkaline bath, and A1/Pb/α-PbO2 composite inert anode materials were obtained. The effects o...The α-PbO2 deposition layers were prepared on the surface of A1/Pb substrates by constant current electrosynthesis from an alkaline bath, and A1/Pb/α-PbO2 composite inert anode materials were obtained. The effects of the bath composition and bath temperature on the electrosynthesis of α-PbO2 were investigated by means of anodic polarization method, the phase structures and surface microstructures of AI/Pb and α-PbO2 deposition layers were tested by means of X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The experimental data have shown that the process of α-PbO2 formation have several stages. The appropriate conditions can effectively improve the formation rate of α-PbO2 and avoid the occurrence of oxygen evolution reaction. The α-PbO2 deposition layer obtained in alkaline bath possesses rhombic structure, and it is composed of well developed spherical unit cells.展开更多
The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The resu...The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 anode.This was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-Mg.Combinative addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge voltage.However,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca anode.Consequently,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.展开更多
Al-Zn-Mg alloys with different Zn/Mg mass ratios were evaluated as sacrificial anodes for cathodic protection of carbon steel in 3.5 wt.%Na Cl solution.The anodes were fabricated from pure Al,Zn and Mg metals using ca...Al-Zn-Mg alloys with different Zn/Mg mass ratios were evaluated as sacrificial anodes for cathodic protection of carbon steel in 3.5 wt.%Na Cl solution.The anodes were fabricated from pure Al,Zn and Mg metals using casting technique.Optical microscopy,SEM-EDS,XRD and electrochemical techniques were used.The results indicated that with decreasing Zn/Mg mass ratio,the grain size ofα(Al)and the particle size of the precipitates decreased while the volume fraction of the precipitates increased.The anode with Zn/Mg mass ratio>4.0 exhibited the lowest corrosion rate,while the anode with Zn/Mg mass ratio<0.62 gave the highest corrosion rate and provided the highest cathodic protection efficiency for carbon steel(AISI 1018).Furthermore,the results showed that the anode with Zn/Mg mass ratio<0.62 exhibited a porous corrosion product compared to the other anodes.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
Mg-6%Al, Mg-5%Pb and Mg-6%Al-5%Pb （mass fraction） alloys were prepared by induction melting with the protection of argon atmosphere. Their electrochemical activations in different electrolyte solutions were investig...Mg-6%Al, Mg-5%Pb and Mg-6%Al-5%Pb （mass fraction） alloys were prepared by induction melting with the protection of argon atmosphere. Their electrochemical activations in different electrolyte solutions were investigated by galvanostatic test. The microstructures of these alloys and their corroded surfaces were studied by scanning electron microscopy, X-ray diffractometry and emission spectrum analysis. The results show that the activation of magnesium is not prominent when only aluminum or lead exists in the magnesium matrix, but the coexistence of the two elements can increase the activation. The activation mechanism of Mg-Al-Pb alloy is dissolving-reprecipitating and there is a synergistic effect between aluminium and lead： the precipitated lead oxides on the surface of the alloy can facilitate the precipitation of Al（OH）3, which can peel the Mg（OH）2 film in the form of 2Mg（OH）2AI（OH）3 and activate the magnesium matrix.展开更多
Mg-6%Al-1%Sn(mass fraction) alloy is a newly developed anode material for seawater activated batteries. The electrochemical properties of Mg-1%Sn, Mg-6%Al and Mg-6%Al-1%Sn alloys are measured by galvanostatic and pote...Mg-6%Al-1%Sn(mass fraction) alloy is a newly developed anode material for seawater activated batteries. The electrochemical properties of Mg-1%Sn, Mg-6%Al and Mg-6%Al-1%Sn alloys are measured by galvanostatic and potentiodynamic tests. Scanning electron microscopy(SEM) with energy dispersive spectrometry(EDS) is used to characterize the microstructures of the experimental alloys. The results show that the Mg-6%Al-1%Sn alloy obtains more negative discharge potential(-1.38 V(vs SCE)) in hot-rolled condition. This is attributed to the fine dynamically recrystallized grains during the hot rolling process. After the experimental alloys are annealed at 473 K for 1 h, the discharge potentials of Mg-6%Al-1%Sn alloy are more negative than those of Mg-6%Al alloy under different current densities. After annealing at 673 K, the discharge potentials of Mg-6%Al-1%Sn alloy become more positive than those of Mg-6%Al alloy. Such phenomenon is due to the coarse grains and the second phase Mg2 Sn. The discharge potentials of Mg-1%Sn shift positively obviously in the discharge process compared with Mg-6%Al-1%Sn alloy. This is due to the corrosion products pasting on the discharge surface, which leads to anode polarization.展开更多
基金National Natural Science Foundation of China(Nos.51204147,51274175,51574206,51574207)Program for International S&T Cooperation Projects of China(No.2014DFA50320)+1 种基金Program for International S&T Cooperation Projects of Shanxi Province(No.201381017)Technological Projects of Shanxi Province(No.20150313002-3)
文摘Electrochemical impendence spectroscopy （EIS） is applied to investigate the dissolution behavior of Al-Zn alloys in 3% NaCl solution at different polarization potentials. A new reaction model is proposed, and the activation mechanism of zinc in Al-Zn alloys is achieved. There are three intermediates in the dissolution process： Znad^＋, Znad^2＋ and Alad^＋, ,of which only Zni can activate Al-Zn alloys. Most Znnd^＋ is produced by β-phase,and the alloys with 2. 3% - 3. 8% （wt） Zn dissolve rapidly. The Al-Zn alloys of heart-shaped EIS are active in 3% NaCl solution, thus EIS characteristic can be used to distinguish the activa-tion of Al-Zn alloys.
文摘采用阳极氧化法制备了Al_2O_3绝缘材料,并制备了以Al_2O_3为绝缘层的并五苯薄膜晶体管器件(OTFT)。Al_2O_3绝缘层经过10 min 350℃氢热处理后,OTFT迁移率比未经氢热处理的增大近20倍,且阈值电压降到了-7 V。Al_2O_3膜MIS结构电容—电压(C–V)特性的平带电压平移量数据表明,Al_2O_3膜经过热处理后,并五苯半导体与Al_2O_3绝缘体界面处以及绝缘体内缺陷态密度显著地降低,Al_2O_3绝缘层和并五苯半导体层之间的接触得到改善,这使得经热处理Al_2O_3膜的OTFT器件性能得到显著的改善。
基金Project(20125314110011) supported by the Specialized Research Fund for the Doctoral Program of the Ministry of Education of ChinaProject(2014FA024) supported by the Key Project of Yunnan Province Applied Basic Research Plan of ChinaProject(51004056) supported by the National Natural Science Foundation of China
文摘The α-PbO2 deposition layers were prepared on the surface of A1/Pb substrates by constant current electrosynthesis from an alkaline bath, and A1/Pb/α-PbO2 composite inert anode materials were obtained. The effects of the bath composition and bath temperature on the electrosynthesis of α-PbO2 were investigated by means of anodic polarization method, the phase structures and surface microstructures of AI/Pb and α-PbO2 deposition layers were tested by means of X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The experimental data have shown that the process of α-PbO2 formation have several stages. The appropriate conditions can effectively improve the formation rate of α-PbO2 and avoid the occurrence of oxygen evolution reaction. The α-PbO2 deposition layer obtained in alkaline bath possesses rhombic structure, and it is composed of well developed spherical unit cells.
基金financial supports from the Key Development Project of Sichuan Province,China (No.2017GZ0399)the National Natural Science Foundation of China (No.52061040)the Open Projects of the Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,China (No.KLATM202003)。
文摘The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 anode.This was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-Mg.Combinative addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge voltage.However,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca anode.Consequently,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.
文摘Al-Zn-Mg alloys with different Zn/Mg mass ratios were evaluated as sacrificial anodes for cathodic protection of carbon steel in 3.5 wt.%Na Cl solution.The anodes were fabricated from pure Al,Zn and Mg metals using casting technique.Optical microscopy,SEM-EDS,XRD and electrochemical techniques were used.The results indicated that with decreasing Zn/Mg mass ratio,the grain size ofα(Al)and the particle size of the precipitates decreased while the volume fraction of the precipitates increased.The anode with Zn/Mg mass ratio>4.0 exhibited the lowest corrosion rate,while the anode with Zn/Mg mass ratio<0.62 gave the highest corrosion rate and provided the highest cathodic protection efficiency for carbon steel(AISI 1018).Furthermore,the results showed that the anode with Zn/Mg mass ratio<0.62 exhibited a porous corrosion product compared to the other anodes.
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.
文摘Mg-6%Al, Mg-5%Pb and Mg-6%Al-5%Pb （mass fraction） alloys were prepared by induction melting with the protection of argon atmosphere. Their electrochemical activations in different electrolyte solutions were investigated by galvanostatic test. The microstructures of these alloys and their corroded surfaces were studied by scanning electron microscopy, X-ray diffractometry and emission spectrum analysis. The results show that the activation of magnesium is not prominent when only aluminum or lead exists in the magnesium matrix, but the coexistence of the two elements can increase the activation. The activation mechanism of Mg-Al-Pb alloy is dissolving-reprecipitating and there is a synergistic effect between aluminium and lead： the precipitated lead oxides on the surface of the alloy can facilitate the precipitation of Al（OH）3, which can peel the Mg（OH）2 film in the form of 2Mg（OH）2AI（OH）3 and activate the magnesium matrix.
基金supported by the Open Fund of the Sate Key Laboratory of Powder Metallurgy(Central South University),China
文摘Mg-6%Al-1%Sn(mass fraction) alloy is a newly developed anode material for seawater activated batteries. The electrochemical properties of Mg-1%Sn, Mg-6%Al and Mg-6%Al-1%Sn alloys are measured by galvanostatic and potentiodynamic tests. Scanning electron microscopy(SEM) with energy dispersive spectrometry(EDS) is used to characterize the microstructures of the experimental alloys. The results show that the Mg-6%Al-1%Sn alloy obtains more negative discharge potential(-1.38 V(vs SCE)) in hot-rolled condition. This is attributed to the fine dynamically recrystallized grains during the hot rolling process. After the experimental alloys are annealed at 473 K for 1 h, the discharge potentials of Mg-6%Al-1%Sn alloy are more negative than those of Mg-6%Al alloy under different current densities. After annealing at 673 K, the discharge potentials of Mg-6%Al-1%Sn alloy become more positive than those of Mg-6%Al alloy. Such phenomenon is due to the coarse grains and the second phase Mg2 Sn. The discharge potentials of Mg-1%Sn shift positively obviously in the discharge process compared with Mg-6%Al-1%Sn alloy. This is due to the corrosion products pasting on the discharge surface, which leads to anode polarization.
