The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
Jiu Ba Wen - One of the best experts on this subject based on the ideXlab platform.
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Effects of acidity and alkalinity on corrosion behaviour of Al–Zn–Mg based Anode Alloy
Journal of Power Sources, 2013Co-Authors: Jiu Ba Wen, Qin ZhangAbstract:Abstract Effects of 1 M HCl, 0.6 M NaCl with different pH values and 4 M NaOH solutions on the corrosion behaviour of Al–5Zn–1Mg–0.02In–0.05Ti–0.5Mn (wt%) Alloy have been investigated using measurements of self-corrosion, potentiodynamic polarization, cyclic polarization experiment combined with open circuit potential technique and scanning electron microscopy. The corrosion behaviour of the Alloy was found to be dependant on the Cl − , OH - ions and pH value. In acidic or slightly neutral solutions, general and pitting corrosion occurred simultaneously. In contrast, exposure to alkaline solutions results in general corrosion which was traced back to the dissolution of the resistive oxidation film on the surface of the Alloy. Experience revealed that the Alloy was susceptible to pitting corrosion in all chloride solution. The Alloy undergoes two types of localized corrosion process, leading to the formation of hemispherical and crystallographic pits. Polarization resistance measurements which are in good agreement with those of self-corrosion, show that the corrosion kinetic is minimized in slightly neutral solutions (pH = 7).
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Effects of Solid Solution Treatment and Rolling Treatment on Electrochemical Properties of Al Anode Alloy
Advanced Materials Research, 2013Co-Authors: Jiu Ba WenAbstract:Effects of solid solution treatment and rolling treatment on microstructure and electrochemical properties of Al-Ga-Mg-Mn-Bi Anode Alloy were investigated by means of SEM and electrochemical measurements. The results show that after solid solution treatment the microstructure segregation of the as-cast Alloy was reduced, the hydrogen evolution was restrained, the corrosion resistance was increased. The open circuit potential moves towards negative after solid solution treatment. Rolling treatment had little impact on the Alloy. The effects of solid solution treatment were superior to rolling treatment.
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In situ corrosion analysis of Al-Zn-In-Mg-Ti-Ce sacrificial Anode Alloy
Materials Characterization, 2012Co-Authors: Jiu Ba Wen, Wenxia ZhaiAbstract:The corrosion behaviour of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt.%) Alloy has been investigated by immersion test, scanning electron microscopy, energy dispersive X-ray detector, electrochemical impedance spectroscopy and electrochemical noise. The results show that there exist different corrosion types of the Alloy in 3.5% NaCl solution with the immersion time. At the initial stage of immersion, pitting due to the precipitates predominates the corrosion with a typical inductive loop at low frequencies in electrochemical impedance spectroscopy. The major precipitates of the Alloy are MgZn{sub 2} and Al{sub 2}CeZn{sub 2} particles. The corrosion potentials of the bulk MgZn{sub 2} and Al{sub 2}CeZn{sub 2} Alloys are negative with respect to that of {alpha}-Al, so the MgZn{sub 2} and Al{sub 2}CeZn{sub 2} precipitates can act as activation centre and cause the pitting. In the late corrosion, a relative uniform corrosion predominates the corrosion process controlled by the dissolution/precipitation of the In ions and characterized by a capacitive loop at medium-high frequencies in electrochemical impedance spectroscopy. The potential noise of the pitting shows larger amplitude fluctuation and lower frequency, but the potential noise of the uniform corrosion occurs with smaller amplitude fluctuation and higher frequency.
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Effect of Quenching on the Corrosion Morphology of Al-Zn-Sn-Ga Anode Alloy
Advanced Materials Research, 2011Co-Authors: Jiu Ba Wen, Jing LingAbstract:In this paper, the Al-Zn-Sn-Ga Anode Alloy was quenched from 460 °C. The influences of corrosion time and different microstructure of the Alloy on its corrosion morphology were investigated to clarify the effect of quenching on the corrosion morphology of the Alloy. The inhomogeneous composition in the as-cast Alloy directly caused various corrosion potential in the Alloy and that the driving force of corrosion was different. Lots of circular corrosion pits and basic uniform composition were observed in the quenching sample. The results reveal that the corrosion morphology of the Anode Alloy is affected by quenching treatment employed.
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HRTEM Investigation of Precipitates in Al-Zn-In-Mg-Ti-Ce Anode Alloy
Advanced Materials Research, 2011Co-Authors: Jing Ling, Jiu Ba Wen, Yan Fu YanAbstract:The precipitates of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt %) Anode Alloy were studied by scanning electron microscopy, X-ray microanalysis, high resolution transmission electron microscopy and selected area electron diffraction analyses in the present work. The results show that the Alloy mainly contains hexagonal structure MgZn2 and tetragonal structure Al2CeZn2 precipitates. From high resolution transmission electron microscopy and selected area electron diffraction, aluminium, Al2CeZn2 and MgZn2 phases have [0 1 -1] Al || [1 -10] Al2CeZn2 || [-1 1 0 1] MgZn2 orientation relation, and Al2CeZn2 and MgZn2 phases have the [0 2 -1] Al2CeZn2 || [0 1 -10] MgZn2 orientation relation.
Jing Ling - One of the best experts on this subject based on the ideXlab platform.
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Effect of Quenching on the Corrosion Morphology of Al-Zn-Sn-Ga Anode Alloy
Advanced Materials Research, 2011Co-Authors: Jiu Ba Wen, Jing LingAbstract:In this paper, the Al-Zn-Sn-Ga Anode Alloy was quenched from 460 °C. The influences of corrosion time and different microstructure of the Alloy on its corrosion morphology were investigated to clarify the effect of quenching on the corrosion morphology of the Alloy. The inhomogeneous composition in the as-cast Alloy directly caused various corrosion potential in the Alloy and that the driving force of corrosion was different. Lots of circular corrosion pits and basic uniform composition were observed in the quenching sample. The results reveal that the corrosion morphology of the Anode Alloy is affected by quenching treatment employed.
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HRTEM Investigation of Precipitates in Al-Zn-In-Mg-Ti-Ce Anode Alloy
Advanced Materials Research, 2011Co-Authors: Jing Ling, Jiu Ba Wen, Yan Fu YanAbstract:The precipitates of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt %) Anode Alloy were studied by scanning electron microscopy, X-ray microanalysis, high resolution transmission electron microscopy and selected area electron diffraction analyses in the present work. The results show that the Alloy mainly contains hexagonal structure MgZn2 and tetragonal structure Al2CeZn2 precipitates. From high resolution transmission electron microscopy and selected area electron diffraction, aluminium, Al2CeZn2 and MgZn2 phases have [0 1 -1] Al || [1 -10] Al2CeZn2 || [-1 1 0 1] MgZn2 orientation relation, and Al2CeZn2 and MgZn2 phases have the [0 2 -1] Al2CeZn2 || [0 1 -10] MgZn2 orientation relation.
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Effects of Ga on the Corrosion Morphology of Al-Zn-Sn-Ga Anode Alloy
Applied Mechanics and Materials, 2011Co-Authors: Jiu Ba Wen, Jing LingAbstract:The corrosion behaviors of Al-Zn-Sn and Al-Zn-Sn-Ga Alloys were investigated according to the results of immersion tests and corrosion morphology observation，and the Fermi energy of the precipitates was calculated by Materials Studio software for discussing the corrosion kinetics of precipitates . The results show that the Al-Zn phase with high Fermi energy (low corrosion potential) dissolved firstly, than caused the forming of Al-Ga amalgam which deposited between passive film and Al matrix. Meanwhile, the Al-Ga phase with higher Fermi energy dissolved too, which made the Al-Zn-Sn-Ga Alloy continue to active, Finally, the Al-Zn-Sn-Ga Alloy formed uniform corrosion morphology due to the effect of Al-Ga amalgam, while Al-Zn-Sn Alloy formed the surface feature with the deep corrosion pits due to the "self-catalysis" mechanism.
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Transmission Electron Microscopy Observations on the Precipitates in Al-Zn-Mg Based Sacrificial Anode Alloy
Materials Science Forum, 2011Co-Authors: Jing Ling, Jiu Ba WenAbstract:nanoscale precipitates in the Al-Zn-In-Mg-Ti-Mn Alloy were investigated by regular and high resolution transmission electron microscopy (TEM and HRTEM) and by selective area electron diffraction (SAED). The cast Alloy contains the hexagonal structure MgZn2 and the orthorhombic structure Al6Mn precipitates, but after aged the precipitates of the cubic structure Mg2Zn11 were found. The Mg2Zn11 precipitates can act as activation centre, make the Alloy pitting. But the activation of Al6Mn precipitates is very little.
Qin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Effects of acidity and alkalinity on corrosion behaviour of Al–Zn–Mg based Anode Alloy
Journal of Power Sources, 2013Co-Authors: Jiu Ba Wen, Qin ZhangAbstract:Abstract Effects of 1 M HCl, 0.6 M NaCl with different pH values and 4 M NaOH solutions on the corrosion behaviour of Al–5Zn–1Mg–0.02In–0.05Ti–0.5Mn (wt%) Alloy have been investigated using measurements of self-corrosion, potentiodynamic polarization, cyclic polarization experiment combined with open circuit potential technique and scanning electron microscopy. The corrosion behaviour of the Alloy was found to be dependant on the Cl − , OH - ions and pH value. In acidic or slightly neutral solutions, general and pitting corrosion occurred simultaneously. In contrast, exposure to alkaline solutions results in general corrosion which was traced back to the dissolution of the resistive oxidation film on the surface of the Alloy. Experience revealed that the Alloy was susceptible to pitting corrosion in all chloride solution. The Alloy undergoes two types of localized corrosion process, leading to the formation of hemispherical and crystallographic pits. Polarization resistance measurements which are in good agreement with those of self-corrosion, show that the corrosion kinetic is minimized in slightly neutral solutions (pH = 7).
Dan Zou - One of the best experts on this subject based on the ideXlab platform.
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An Integrated Process to Recover NiMH Battery Anode Alloy with Selective Leaching and Multi-stage Extraction
Industrial & Engineering Chemistry Research, 2017Co-Authors: Chuanying Liu, Yuefeng Deng, Ji Chen, Dan ZouAbstract:Hydrometallurgy is a widely studied recovery process to recover NiMH battery, but the large chemical consumption restricted its application in industry. To achieve a low chemical consumption recovery process of NiMH battery Anode Alloy, an integrated process with selective leaching and multi-stage extraction was designed. In selective leaching, the leaching procedure was divided into four stages. The acid used could be reacted with the battery Anode Alloy totally except in the last stage. The metal components of the Alloy have different reaction activities with acid, they were leached into liquor by the sequence: La>Pr>Nd>Ce>Al>Mn>Co>Ni. Hence, the selectivity of metals was achieved to make the following extraction much easier. The total chemical consumption was calculated by the ratio of UMAC/UMACmin and S, which in this integrated process was 60% less than in traditional recovery process. Through this recovery process, the recovery rate of rare earth elements (REEs) reached 90.5%, and the purity of REO ...
Roman V. Denys - One of the best experts on this subject based on the ideXlab platform.
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studies of zr based c15 type metal hydride battery Anode Alloys prepared by rapid solidification
Journal of Alloys and Compounds, 2019Co-Authors: Ika Dewi Wijayanti, Live Molmen, Matylda N Guzik, Roman V. Denys, Stephane Gorsse, K. Young, V A YartysAbstract:Abstract The objective of the present work was to study an interrelation between the conditions of the rapid solidification casting and electrochemical properties of a C15 Laves-type Zr-based metal hydride battery Anode Alloy. A 7-component overstoichiometric with B/A>2 Alloy (Ni + Mn + V + Fe/Zr + Ti + La = 2.078) was Zr- and Ni-rich. Melt spinning was performed using as cast mother ingot at different rotation speeds of 5, 16.5, and 33 Hz with a 20-cm diameter Cu cooling wheel. The phase composition and morphology of the ribbons were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) along with X-ray energy dispersive spectroscopy (EDS). Partial Mn vaporization took place during the melt spinning and became more pronounced with the increase in the quenching rate at higher wheel rotation speeds. The SEM study showed a successful refinement and a more homogeneous distribution of La in the melt-spun Alloys. However, the Alloys demonstrated a more difficult activation performance as compared to the as-cast sample which was associated with introduction of Zr into the composition of the secondary La-and Ni-rich phase when quenching the melt. Presence of Zr in the secondary phase results in inferior rate of its hydrogenation. The formed during the rapid solidification (La,Zr) (Ni,Mn) secondary phase also contained a significant amount of oxygen additionally worsening the activation performance. The grain size gradually decreased from 3.5 μm in the as-cast Alloy to approximately 250 nm for the melt spun sample obtained at the highest cooling rate. The two-phase Alloys contained a mixture of two Laves type intermetallics, C15 and C14 ones. The abundance of the secondary C14 phase decreased with increase of the cooling rate as compared to the as-cast sample. The electrochemical performance was significantly affected by the compositional and microstructural changes associated with the variation in the cooling rate. The highest electrochemical discharge capacity of 414 mAh/g was obtained for the 16.5 Hz melt spun rate because of an optimized composition of the Laves phase. Furthermore, the diffusion coefficient of hydrogen in this Alloy was the highest in a full state of charge, which indicates that faster hydrogen diffusion and shorter hydrogen diffusion paths were achieved via an application of the rapid solidification process. An optimization of the rapid solidification conditions is required to improve an activation behavior of the studied Laves types metal hydride Anode Alloys.
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In situ neutron powder diffraction study of phase-structural transformations in the La–Mg–Ni battery Anode Alloy
Journal of Alloys and Compounds, 2016Co-Authors: Chubin Wan, Roman V. Denys, Volodymyr A. YartysAbstract:Abstract This work was focused on studies of temperature-induced phase-structural transformations in the as-cast La 2 MgNi 9 metal hydride battery electrode Alloy. The interactions in the Alloy were studied by in situ neutron powder diffraction at temperatures ranging from 300 K to 1273 K. Initial Alloy is multi-phase structured, containing six different intermetallics with five stoichiometric compositions. These include the targeted rhombohedral La 2 MgNi 9 as the main phase constituent, together with three electrochemically active intermetallics, La 3 MgNi 14 (3R), La 4 MgNi 19 (2H) and La 4 MgNi 19 (3R). Furthermore, the Alloy contained two “ballast” intermetallics, LaNi 5 and LaMgNi 4 . Various transformations take place on heating, leading to the significant changes in the contents of the constituent intermetallics, first of all to the disappearance of LaNi 5 and LaMgNi 4 . Thermal volume expansions of the studied intermetallics were well fitted by the linear dependences and resulted in similar values of 4.3–5.5 vol.% at 1223 K as compared to 300 K.