The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lijian Meng - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of freestanding si nanowire arrays by one step template free electro Deoxidation of sio2 in a molten salt
Chemical Communications, 2013Co-Authors: Ji Zhao, Pinliang Ying, Wenhua Zhang, Lijian MengAbstract:This communication presents a novel kind of silicon nanomaterial: freestanding Si nanowire arrays (Si NWAs), which are synthesized facilely by one-step template-free electro-Deoxidation of SiO2 in molten CaCl2. The self-assembling growth process of this material is also investigated preliminarily.
Derek J Fray - One of the best experts on this subject based on the ideXlab platform.
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dc voltammetry of electro Deoxidation of solid oxides
Chemical Reviews, 2013Co-Authors: Amr M Abdelkader, Tripuraneni K Kilby, Derek J FrayAbstract:1. Introduction 28632. Theoretical Considerations 28643. Electro-Deoxidation under Controlled Voltage orPotential 28663.1. Earlier Attempts to Describe the ReductionMechanism 28663.2. Three-Phase Interline (3PI) PropagationModels 28673.3. Alkali Ternary Oxides Intermediates 28673.3.1. Niobium Oxide 28673.3.2. Tantalum Oxide 28683.3.3. Chromium Oxide 28683.3.4. Titanium Oxide 28683.3.5. Zirconium Oxide 28703.3.6. Tungsten Oxide 28703.3.7. Aluminum Oxide 28703.4. Electro-Deoxidation of Mixed Oxides andOxide Solid Solutions 28713.5. Attempts to Use Inert Anode 28734. Cyclic Voltammetry 28744.1. Understanding the Cathodic ReductionReactions 28744.2. Determining the Optimum Operation Po-tential 28764.3. Exploring the Surface Phenomenon 28774.4. Studying the Complex Side Processes andDetecting the High Temperature Intermedi-ate Phases 28774.5. Providing Direct Insights into the Kinetics ofElectrode Reactions 28785. Electro-Deoxidation under Constant CurrentChronopotentiometry 28796. Summary and Future Direction 2882Author Information 2883Corresponding Author 2883Notes 2883Biographies 2883References 2884
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electrochemical synthesis of hafnium carbide powder in molten chloride bath and its densification
Journal of The European Ceramic Society, 2012Co-Authors: Amr M Abdelkader, Derek J FrayAbstract:Abstract Nanocrystalline powder of hafnium-rich-HfC has been successfully synthesised by the electro-Deoxidation of HfO2–carbon precursors in molten chloride. The progress of the solid state reduction was monitored ex situ by analysing partially reduced samples using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It has been shown that the reduction started by converting HfO2 to CaHfO3 and an oxycarbide phase of the form HfCxO2(1−x). The CaHfO3 phase then also reduced to give HfCxO2(1−x), which subsequently reduced to HfC by ionising oxygen. The morphological analysis indicated almost no growth in the grain size occurred during the course of the electro-Deoxidation. This investigation showed some loss of carbon during the electro-Deoxidation resulted in metallic rich HfC. The synthesised powder exhibited better sinterability than the commercial HfC powder. Using the synthesised powder, fully dense monolithic HfC ceramics were produced by pressureless sintering at 1973 K with average grain size of about 3 μm.
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production of niti shape memory alloys via electro Deoxidation utilizing an inert anode
Electrochimica Acta, 2010Co-Authors: Shuqiang Jiao, Linlin Zhang, Derek J FrayAbstract:Abstract NiTi shape memory alloys (SMA) with equiatomic composition of Ni and Ti were prepared by electro-Deoxidation, in molten calcium chloride, at 950 °C. Constant voltage electro-Deoxidation was conducted using a NiTiO 3 cathode, and either a carbon anode or a novel CaRuO 3 /CaTiO 3 composite inert anode. Both anode materials successfully allowed NiTi shape memory alloy to be obtained. The primary difference is that molecular oxygen was produced on the inert anode, instead of environmentally undesired CO 2 greenhouse gases on the carbon anode. Indeed, it was found that carbon could successfully be substituted with conductive calcium titanate–calcium ruthenate composites for electro-Deoxidation. Furthermore, DSC was used to analyze the phase transformation of NiTi shape memory alloys, with results revealing the existence of reversible martensite–austenite phase transformations during the cooling and heating process.
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direct electrolytic reduction of solid alumina using molten calcium chloride alkali chloride electrolytes
Journal of Applied Electrochemistry, 2009Co-Authors: Xiao Y Yan, Derek J FrayAbstract:Solid alumina was reduced by electro-Deoxidation to aluminium metal containing 1.8 and 5.4 at% Ca in molten CaCl2–NaCl and CaCl2–LiCl electrolytes at 900 °C, respectively. The potential-pO2− diagrams for the Al–O–M–Cl (M = Na or Li, or/and Ca) system were constructed to predict equilibrium phase relationships in the electrolytes at 700 and 900 °C. It was found that calcium aluminates were formed as the main intermediate reaction products and were subsequently reduced to form the Al-rich Al–Ca alloys during electro-Deoxidation. Calcium and/or lithium, at reduced activities, were created at the cathode especially at 700 °C at the same time as the ionization of the oxygen from the cathode, which resulted in Al2Ca formation. The experimental results were consistent with the thermodynamic predictions.
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Electrochemical Deoxidation of Titanium Foam in Molten Calcium Chloride
Metallurgical and Materials Transactions B, 2007Co-Authors: Prabhat K. Tripathy, Maxime Gauthier, Derek J FrayAbstract:Titanium foam, prepared by using a patented powder-metallurgy–based process involving a powder blend that was molded, foamed, and sintered using a three-step thermal treatment, was deoxidized in a molten CaCl_2 bath. The polarization experiments were carried out by cathodically polarizing the foam (working electrode) against a counter (graphite) electrode. Under constant potential (polarization) mode, the dominant mechanism of Deoxidation was the ionization of oxygen, present in the foam, and its subsequent discharge, as CO_2/CO, at the anode surface. More than ∼85 pct oxygen could be effectively removed by carrying out the electro-Deoxidation experiments in fresh and pre-electrolyzed melt(s) at an electrolyte temperature of 950 °C. Scanning electron microscopy–energy dispersive X-ray (SEM-EDX) detection of the deoxidized foams did not show a presence of any inclusion(s) or secondary phase(s).
Toru H Okabe - One of the best experts on this subject based on the ideXlab platform.
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ultimate Deoxidation method of titanium utilizing y yocl ycl 3 equilibrium
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2020Co-Authors: Akihiro Iizuka, Takanari Ouchi, Toru H OkabeAbstract:Deoxidation methods of titanium (Ti) scrap and Ti powder have become increasingly important in recent years. Some rare earth (RE) metals with strong deoxidizing capabilities, including Y, La, Ce, and Ho, are candidate agents for the development of a new Deoxidation technology. In this study, a new method was developed to directly remove oxygen (O) from Ti using the Y/YOCl/YCl3 equilibrium. According to the calculation based on available thermodynamic data in the literature, the O concentration in β-Ti can be reduced to less than 10 ppm O at 1300 K (1027 °C) in the Y/YOCl/YCl3 equilibrium. To demonstrate the effectiveness of this method using the Y/YOCl/YCl3 equilibrium, the Deoxidation limits of Ti samples using Y metal in YCl3 (l) or in YCl3-NaCl-KCl (l) at 1300 K (1027 °C) were experimentally investigated in this study. As a result, the O concentrations in the Ti samples were from 30 to 60 ppm O in YCl3 (l). This result revealed that Ti with extremely low O concentration can be reliably obtained using the RE/REOCl/RECl3 equilibrium for the first time. The establishment of this process will realize efficient recycling of Ti scrap and production of low O concentration Ti powder, which contribute to the large-scale use of Ti products.
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Electrochemical Deoxidation of Titanium in Molten MgCl_2–YCl_3
Metallurgical and Materials Transactions B, 2019Co-Authors: Chenyi Zheng, Takanari Ouchi, Yu-ki Taninouchi, Lingxin Kong, Toru H OkabeAbstract:A new electrochemical Deoxidation process for Ti, where a mixture of magnesium chloride and yttrium chloride (MgCl_2–YCl_3) is used as flux, was developed. In the new process, Ti and carbon were used as the cathode and anode, respectively. By elucidating the system using an E -pO^2− diagram and the experimental results, the reaction mechanism was proposed. Mg is deposited on the Ti cathode and reduces the oxygen in Ti to oxide ions (O^2−). The activity of the generated O^2−, $$a_{\text O^{2-}}$$ a O 2 - , in the system is effectively kept at a low level by the formation of yttrium oxychloride, and is further decreased by the electrochemical oxidation reaction on the anode. The process effectively deoxidizes Ti to the level of 100 mass ppm of oxygen concentration at 1200 K. In addition, the oxygen concentration in the Ti sample was maintained at the level of 500 mass ppm O even with the addition of O^2− sources. Furthermore, a new concept of the industrial Ti-recycling process based on this new Deoxidation process was depicted. The obtained results indicate that this new Deoxidation technique can be applied in the recycling process of Ti scrap containing a large amount of oxygen.
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Deoxidation of Titanium Using Mg as Deoxidant in MgCl_2-YCl_3 Flux
Metallurgical and Materials Transactions B, 2019Co-Authors: Chenyi Zheng, Takanari Ouchi, Akihiro Iizuka, Yu-ki Taninouchi, Toru H OkabeAbstract:To reduce the oxygen level in titanium (Ti) to less than 1000 mass ppm O, using magnesium as the deoxidant at 1300 K (1027 °C), the activity of the Deoxidation product (MgO), i.e. , a _MgO, in the system must be reduced to less than 0.04, from a thermodynamic viewpoint. In this study, we developed a new Deoxidation technique for Ti, by adding yttrium chloride (YCl_3) to magnesium chloride (MgCl_2) flux, which effectively decreases and maintains the a _MgO in the system at a low level, via the formation of yttrium oxychloride (YOCl). Through thermodynamic assessment using a $$ p_{{{\text{O}}_{ 2} }} {\text{-}}p_{{{\text{Cl}}_{ 2} }} $$ p O 2 - p Cl 2 diagram, as well as experiments, the Deoxidation of Ti to an oxygen level below 1000 mass ppm O, via the reaction O (in Ti) + Mg + YCl_3 → MgCl_2 + YOCl, was confirmed. Furthermore, using the E -pO^2− diagram of the M-O-Cl system (M = Y, Mg), the possibility of electrochemical Deoxidation is discussed. In the MgCl_2-YCl_3 flux, Mg deposits on the Ti cathode and simultaneously deoxidizes it. The activity of the Deoxidation product, MgO, decreases due to the formation of YOCl and/or the electrochemical oxidation of oxide ions on the carbon anode; thus, the Deoxidation of Ti becomes feasible. This new Deoxidation technique using rare-earth-containing MgCl_2 flux can be applied to the recycling of Ti scraps, in the future.
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electrochemical Deoxidation of yttrium oxygen solid solutions
Journal of Alloys and Compounds, 1996Co-Authors: Toru H Okabe, Toshio Oishi, Katsutoshi Ono, T N Deura, Donald R SadowayAbstract:Oxygen was removed from yttrium by an electrochemical method in which the metal is made the cathode in a cell consisting of a carbon anode and molten CaCl2 electrolyte. At 1223 K yttrium containing 5700 ppm oxygen was deoxidized down to less than 100 ppm. The method can be used to deoxidize other highly reactive metals. Furthermore, in principle it should be possible to remove other impurities besides oxygen.
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electrochemical Deoxidation of titanium
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 1993Co-Authors: Toru H Okabe, Toshio Oishi, Marcelo Nakamura, Katsutoshi OnoAbstract:Removal of oxygen in titanium using an electrochemical technique was examined at temperatures around 1223 K with the purpose of obtaining nearly oxygen-free titanium. Titanium and carbon electrodes, immersed in molten CaCl2, served as cathode and anode, respectively, with an external DC source. CaCl2 was employed to produce the deoxidant calcium and to facilitate the reaction by decreasing the activity of the by-product CaO. By applying about 3 V between the electrodes, the calcium potential in CaCl2 was increased at the titanium cathode surface and titanium samples of the cathode could be deoxidized by the electrolytically produced deoxidant calcium or by calcium of high activity in the CaCl2 flux. Resulting O2− species, mainly present as the Deoxidation product CaO in the flux, reacted at the carbon anode to form CO (or CO2) gas which was removed from the system. Titanium wires containing 1400 mass ppm oxygen were deoxidized to less than 100 mass ppm, whereas the carbon concentration increased by about 50 mass ppm. In some cases, the oxygen concentration in titanium samples was lowered to a level less than 10 mass ppm that could be determined by conventional inert gas fusion analysis. The behavior of contaminants, such as carbon and nitrogen, is also discussed.
Ji Zhao - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of freestanding si nanowire arrays by one step template free electro Deoxidation of sio2 in a molten salt
Chemical Communications, 2013Co-Authors: Ji Zhao, Pinliang Ying, Wenhua Zhang, Lijian MengAbstract:This communication presents a novel kind of silicon nanomaterial: freestanding Si nanowire arrays (Si NWAs), which are synthesized facilely by one-step template-free electro-Deoxidation of SiO2 in molten CaCl2. The self-assembling growth process of this material is also investigated preliminarily.
Zonghui Yuan - One of the best experts on this subject based on the ideXlab platform.
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Deoxidation rates play a critical role in dna damage mediated by important synthetic drugs quinoxaline 1 4 dioxides
Chemical Research in Toxicology, 2015Co-Authors: Xu Wang, Huahai Zhang, Lingli Huang, Yuanhu Pan, Dongmei Chen, Guyue Cheng, Haihong Hao, Yanfei Tao, Zhenli Liu, Zonghui YuanAbstract:Quinoxaline 1,4-dioxides (QdNOs) are synthetic agents with a wide range of biological activities. However, the mechanism of DNA damage mediated by QdNOs is far from clear. Five classical QdNOs, quinocetone (QCT), mequindox (MEQ), carbadox (CBX), olaquindox (OLA), and cyadox (CYA), were used to investigate the genotoxicity of QdNOs. The Deoxidation rate of QdNOs was presumed to play a role in their genotoxicity. Deoxidation rates of QdNOs in both rat and pig liver microsomes were investigated using LC/MS-IT/TOF, and their relative quantification was achieved with HPLC. To reveal the relationships between the Deoxidation rate and genotoxicity, cell damage, oxidative stress, and DNA damage were detected. Under low oxygen conditions, the rank order of the desoxy and bidesoxy rates in rat and pig liver microsomes was QCT < CBX < MEQ < OLA < CYA and QCT < MEQ < CBX < OLA < CYA, respectively. Only desoxy-quinoxalines were detected under aerobic conditions. The concentrations of deoxidized metabolites under low o...
