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Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 750-763页

作者： Jia Liu Shuanglu Duan Xiaokang Yue Ningsong Qu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

关键词： electrochemical machining dissolution behavior β-CEZ titanium alloy polarization curve current efficiency

Optimal V_(2)O_(3) extraction by sustainable vanadate electrolysis in molten salts

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Tungsten 2024年第1期6卷 141-149页

作者： Bao-Yan Feng Zhong-Hua Zhao Yong-Zheng Jia Jia-Liang An Ming-Yong Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China

Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) extraction.In this paper,the solubilities of various vanadates(i.e.NaVO_(3),Na_(4)V_(2)O_(7) and Na_(3)VO_(4))in NaCl molten salt are measured.The dependences of V_(2)O_(3) extraction on vanadate form,anode material and molten salt system are studied.A long-term electrolysis is carried out.The result indicates that the solubilities of all vanadates are high and meet electrolytic requirements.Compared to Na_(4)V_(2)O_(7) and Na_(3)VO_(4),NaVO_(3) exhibits larger current efficiency and lower electricity consumption.By using SnO_(2) anode instead of graphite anode,the current efficiency of NaVO_(3) electrolysis can be increased to 58.1%and carbon pollution is avoided at 700℃.The extraction rate of V_(2)O_(3) reaches 81.3%after long-term electrolysis of 51 h.This work optimizes the electrochemical preparation process of V_(2)O_(3) from various vanadates and contributes to the improvement of current efficiency and extraction rate.

关键词： Molten salt electrolysis Vanadate Vanadium trioxide current efficiency

current efficiency in electro-winning of lanthanum and cerium metals from molten chloride electrolytes

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Rare Metals 2013年第3期32卷 305-311页

作者： Deepak Kumar Sahoo Harvinderpal Singh Nagaiyar Krishnamurthy Rare Earths Development Section Bhabha Atomic Research Centre Fusion Reactor Materials Section Bhabha Atomic Research Centre

The objective of this study is to prepare lan- thanum and cerium metals by fused salt electrolysis of their anhydrous chloride in molten media such as LiCl-KCl, NaCl-KCl, KCl, NaCl, and LiCl and to characterize the metal deposit by X-ray diffraction, energy dispersive X-ray fluorescence, and inductive coupled plasma-atomic emis- sion spectroscopy. Deposit metal of purity more than 99 % was obtained in each of the experiments. The entire process starting from preparation of anhydrous lanthanum/cerium chloride to electrolysis yielding of metal deposits has been described. The effect of process parameters such as tem- perature, electrolyte composition, and current density on the current efficiency was studied. All these parameters were varied to get the highest current efficiency and metal yield. The major non-rare earth impurities with the deposit are found to be Fe, Cr, and Ni along with - 1× 10^-3 of total gaseous impurities.

关键词： Fused salt electrolysis current density current efficiency Rare earths

current efficiency of Low Temperature Aluminum Electrolysis Studied by Neural Network

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 107-110页

作者： Huimin Lu Zuxian Qiu Keming Fang Fuming Wang Yanruo Hong( Metallurgy School, University of Science and Technology Beijing, Beijing 100083, China)( Department of Nonferrous Metallurgy, Northeastern University, Shenyang 110006, China) Metallurgy School University of Science and Technology Beijing Beijing 100083 China Department of Nonferrous Metallurgy Northeastern University Shenyang 110006 China

A prediction model for current efficiency (CE) of low temperature aluminum electrolysis (LTAE) with the low molar ratioelectfolyte of Na3AIF6-AIF3 - CaF2-MgF2-LiF -Al2O3 system was investigated based on artificial neural network principles. The nonlinearmapping between CE of LATE and various electrolytic conditions was obtained from a number of experimental data and used to predictCE of LATE. The trsined neural networks possessed high precision and resulted in a good predicting effect. As a result, attificial neuralnetworks as a new cooperating and predicting technology provide a new approach to the further studies on low temperature aluminumelectrolysis.

关键词： low temperatre aluminum electrolysis current efficiency neural network prediction model low molar ratio electrolyte

Dependency of the pulsed electrochemical machining characteristics of Inconel 718 in NaNO_(3)solution on the pulse current

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Science China(Technological Sciences) 2022年第10期65卷 2485-2502页

作者： WANG JingTao XU ZhengYang GENG TianYu ZHU Di College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Pulsed electrochemical machining(PECM)has attracted increasing interest as a technique to improve material dissolution localization and surface quality.This work systematically investigates the effects of pulse current on the surface morphology,profile accuracy,and corrosion behavior of Inconel 718(IN718)in NaNO_(3)solution.Polarization behavior reveals that IN718 in NaNO_(3)solution during pulse current machining exhibited significant passive,transpassive,and re-passive characteristics.The passive film generated at the re-passive state contained some oxides and had a loose porous structure.The critical value for the quantity of electric charge to rupture the passive film was determined to be 26.88℃cm^(−2).The current efficiency indicates that the material removal rate of IN718 in NaNO_(3)solution during pulse current machining was nonlinear.The PECM experiments indicate that the loading process of the electrical double layer was prolonged with an increased workpiece scale,i.e.,the loading process of the electrical double layer lasted for the entire pulse-on time when the workpiece scale was 100 mm^(2)at a frequency of more than 10 kHz regardless of the duty cycle.A pulse current with a short pulse length and short pulse period improved the profile accuracy,as did the low applied voltage and small workpiece scale.The dissolution mechanism of IN718 in NaNO_(3)solution was also investigated based on the effective pulse current time.Finally,the leading-edge structure of a ruled blade with good dimensional accuracy and surface quality was successfully fabricated.The maximum deviations of the machined profile were effectively restricted within 0.057 mm,and the surface roughness was Ra=0.358μm.

关键词： pulsed electrochemical machining corrosion behavior current efficiency blade leading edge machining quality

Influences of CeO_(2)morphology on enhanced performance of electro-Fenton for wastewater treatment

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Journal of Rare Earths 2022年第12期40卷 1870-1877,I0002页

作者： Jingjing Hu Bei Wu Lei Chen Chengcheng Song Huifang Yang Fei Long Jie Sun Ru'an Chi Hubei Novel Reactor&Green Chemical Technology Key Laboratory Key Laboratory for Green Chemical Process of Ministry of EducationXingfa School of Mining EngineeringWuhan Institute of TechnologyWuhan 430073China Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission&Ministry of Education Hubei ProvinceCollege of Resource and Environmental ScienceSouth-Central University for NationalitiesWuhan 430074China

As a kind of rare-earth oxide,CeO_(2)has been considered as a great potential material for its abundant oxygen vacancies and catalysis activity in wastewater treatment.In this study,three ceria samples with different morphological structure were prepared,and their effect on contaminates degradation in electro-Fenton(E-Fenton)system was investigated.It is found that the morphology of CeO_(2)has great influence on promoting the performance of E-Fenton process.The rod-like CeO_(2)(R-CeO_(2))induced EFenton system shows higher azo dye X3 B removal and mineralization rates than cubs(C-CeO_(2))and octahedrons(O-CeO_(2)),and the degradation kinetic rate constants are 0.28,0.169 and 0.181 min^(-1)respectively,already surpass that of the blank one(0.120 min^(-1)).The H_(2)O_(2)generation capacity of R-CeO_(2)induced E-Fenton system is also superior to the others,and the corresponding Faraday current efficiency even increases to 166.2%at 2.5 min.Characterizations by scanning-transmission electron microscopy(STEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),electron spin resonance(ESR),Raman spectroscopy were conducted to disclose the mystery behind this phenomenon.The results indicate that the difference of surface oxygen vacancy density in different shaped CeO_(2)acts as a magic driving force for the accelerated oxygen reduction,and then leads to the enhanced degradation efficiency of E-Fenton system.This work provides a new insight into the development and application of rare-earth elements based catalyst in E-Fenton technology.

关键词： CeO_(2) Electro-Fenton current efficiency Exposed facets H_(2)O_(2) Morphology

Enhanced efficiency of top-emission InP-based green quantum dot light-emitting diodes with optimized angular distribution

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Nano Research 2021年第11期14卷 4243-4249页

作者： Dong Li Jingwen Feng Youqin Zhu Zhigao Lu Chen Pei Zhuo Chen Yanzhao Li Xinguo Li Xiaoguang Xu BOE Technology Group Co. Ltd.Beijing100176China

High resolution and wide color gamut are two key requirements for novel display technologies. Owing to the distinguishing advantages over conventional displays, such as intrinsic wide color gamut and the possibility to achieve high resolution, quantum dot light-emitting diodes (QLED) have drawn considerable attention in recent years. On the other hand, indium phosphide quantum dots (InP QDs) have shown a great potential as a replacement for cadmium selenide (CdSe) QDs in display applications due to the inherent toxicity of cadmium-based QDs. In this study, we investigate a top-emission InP-based green QLED with optimized angular distribution. By adjusting the electrical and optical architecture, the device exhibits improved properties with a maximum current efficiency of 30.1 cd/A and a narrowed full width at half maxima (FWHM)of 31 nm, which are the best results ever reported to our knowledge.

关键词： Cd-free quantum dots quantum dot light-emitting diode(QLED) top-emission angular distribution current efficiency

efficiency of a blue organic light-emitting diode enhanced by inserting charge control layers into the emission region

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Chinese Physics B 2013年第4期22卷 504-507页

作者：白娟娟吴晓明华玉林穆雪毕文涛苏跃举焦志强申利莹印寿根郑加金 Key Laboratory of Display Materials and Photoelectric Devices Ministry of Education Tianjin Key Laboratory of Photoelectric Materials and Devices School of Materials Science and Engineering Tianjin University of Technology College of Optoelectronics Engineering Nanjing University of Posts and Telecommunications

We demonstrate high current efficiency of a blue fluorescent organic light-emitting diode （OLED） by using the charge control layers （CCLs） based on Alq3 . The CCLs that are inserted into the emitting layers （EMLs） could impede the hole injection and facilitate the electron transport, which can improve the carrier balance and further expand the exciton generation region. The maximal current efficiency of the optimal device is 5.89 cd/A at 1.81 mA/cm2 , which is about 2.19 times higher than that of the control device （CD） without the CCL, and the maximal luminance is 19.660 cd/m2 at 12V. The device shows a good color stability though the green light emitting material Alq3 is introduced as the CCL in the EML, but it has a poor lifetime due to the formation of cationic Alq3 species.

关键词： organic light-emitting devices charge control layer current efficiency

Influence of anode current density on carbon parasitic reactions during electrolysis

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Chinese Journal of Chemical Engineering 2021年第11期34卷 314-319页

作者： Tongxiang Ma Lang Zhao Yu Yang Liwen Hu Shengfu Zhang Meilong Hu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

In the electro-deoxidation process,carbon parasitic reaction(CO_(3)^(2-)+4e–=C+3O^(2-))usually occurs when using carbon materials as the anode,which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process.The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density.The results indicate that lower graphite anode area can achieve higher current density,which is helpful to increase the nucleation site of CO_(2) bubbles.Most of CO_(2) would be released from the anode instead of dissolution in the molten CaCl_(2) and reacting with O^(2-)to form CO_(3)^(2-),thus decreasing the carbon parasitic reaction of the process.Furthermore,the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm^(2),CO_(2) concentration in the released gases increases significantly,the carbon mass content in the final metal product decreased from 1.09%to 0.13%,and the current efficiency increased from 6.65%to 36.50%.This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.

关键词： Anode area Anode current density Carbon parasitic reactions current efficiency