The Experts below are selected from a list of 6390 Experts worldwide ranked by ideXlab platform
Fan Jiang - One of the best experts on this subject based on the ideXlab platform.
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effect of Cathodic Current Density on performance of tungsten coatings on molybdenum prepared by electrodeposition in molten salt
Applied Surface Science, 2016Co-Authors: Fan JiangAbstract:Abstract Smooth tungsten coatings were prepared at Current Density below 70 mA cm −2 by electrodeposition on molybdenum substrate from Na 2 WO 4 -WO 3 -melt at 1173 K in air atmosphere. As the Current Density reached up to 90 mA cm −2 , many significant nodules were observed on the surface of the coating. Surface characterization, microstructure and mechanical properties were performed on the tungsten coatings. As the increasing of Current Density, the preferred orientation of the coatings changed to (2 0 0). All coatings exhibited columnar-grained-crystalline. There was about a 2 μm thick diffusion layer between tungsten coating and molybdenum substrate. The bending test revealed the tungsten coating had –good bonding strength with the molybdenum substrate. There is a down trend of the grain size of the coating on molybdenum as the Current Density increased from 30 mA cm −2 to 50 mA cm −2 . The coating obtained at 50 mA cm −2 had a minimum grain size of 4.57 μm, while the microhardness of this coating reached to a maximum value of 495 HV.
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electrodeposition of metallic tungsten coating from binary oxide molten salt on low activation steel substrate
Journal of Nuclear Materials, 2013Co-Authors: Yanhong Liu, Yingchun Zhang, Fan Jiang, Ningbo SunAbstract:Abstract Tungsten is considered a promising plasma facing armor material for future fusion devices. An electrodeposited metallic tungsten coating from Na 2 WO 4 –WO 3 binary oxide molten salt on low activation steel (LAS) substrate was investigated in this paper. Tungsten coatings were deposited under various pulsed Currents conditions at 1173 K in atmosphere. Cathodic Current Density and pulsed duty cycle were investigated for pulsed Current electrolysis. The crystal structure and microstructure of tungsten coatings were characterized by X-ray diffractometry, scanning electron microscopy, and energy X-ray dispersive analysis techniques. The results indicated that pulsed Current Density and duty cycle significantly influence tungsten nucleation and electro-crystallization phenomena. The average grain size of the coating becomes much larger with increasing Cathodic Current Density, which demonstrates that appropriate high Cathodic Current Density can accelerate the growth of grains on the surface of the substrate. The micro-hardness of tungsten coatings increases with the increasing thickness of coatings; the maximum micro-hardness is 482 HV. The prepared tungsten coatings have a smooth surface, a porosity of less than 1%, and an oxygen content of 0.024 wt%.
Xing Zhang - One of the best experts on this subject based on the ideXlab platform.
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molybdenum phosphide carbon nanotube hybrids as ph universal electrocatalysts for hydrogen evolution reaction
Advanced Functional Materials, 2018Co-Authors: Xing Zhang, Linjie Zhang, Feng Zhou, Yongye Liang, Ruihu WangAbstract:Molybdenum phosphide (MoP) has received increasing attention due to its high catalytic activity in hydrogen evolution reaction (HER). However, it remains difficult to construct well-defined MoP nanostructures with large Density of active sites and high intrinsic activity. Here, a facile and general method is reported to synthesize an MoP/carbon nanotube (CNT) hybrid featuring small-sized and well-crystallized MoP nanoparticles uniformly coated on the sidewalls of multiwalled CNT. The MoP/CNT hybrid exhibits impressive HER activities in pH-universal electrolytes, and requires the overpotentials as low as 83, 102, and 86 mV to achieve a Cathodic Current Density of 10 mA cm−2 in acidic 0.5 m H2SO4, neutral 1 m phosphate buffer solution, and alkaline 1 m KOH electrolytes, respectively. It is found that the crystallinity of MoP has significant influence on HER activity. This study provides a new design strategy to construct MoP nanostructures for optimizing its catalytic performance.
Yunying Xing - One of the best experts on this subject based on the ideXlab platform.
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effect of the Cathodic Current Density on the sub surface concentration of hydrogen in x80 pipeline steels under Cathodic protection
International Journal of Hydrogen Energy, 2017Co-Authors: Lei Zhang, Wenhai Cao, Zhu Wang, Yunying XingAbstract:Abstract The effect of the Cathodic Current Density (i) on the permeation of hydrogen through API X80 pipeline steels under Cathodic protection was investigated using an electrochemical permeation technique. A proper equation was presented for determining the sub-surface concentration of hydrogen (c0). With the aim to enhance the predictive capabilities of the proposed equation, actual environmental parameters such as temperature were considered. The experimental results reported herein clarified the relationship between c0 and i. It was clearly shown that the ratio of c0 to the specimen thickness (L) was proportional to √ i when i was lower than its critical value (iH). On the other hand, for i values above iH, c0 was equal to the saturation hydrogen content because of reaction equilibrium. Furthermore, iH was found to be dependent on temperature (i.e., iH increased with the test temperature).
Xingpeng Guo - One of the best experts on this subject based on the ideXlab platform.
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The effects of Cl- ion concentration and relative humidity on atmospheric corrosion behaviour of PCB-Cu under adsorbed thin electrolyte layer
Corrosion Science, 2011Co-Authors: Hualiang Huang, Zehua Dong, Zhenyu Chen, Xingpeng GuoAbstract:The effects of Cl- ion concentration and relative humidity on atmospheric corrosion behaviour of PCB-Cu under adsorbed thin electrolyte layer were investigated by Cathodic polarization curves and electrochemical impedance spectroscopy. Results indicated that the Cathodic process of PCB-Cu corrosion was dominated by the reduction of oxygen and corrosion products. The Cathodic Current Density increased with increasing relative humidity and Cl- ion concentration. The corrosion rate was initially dominated by oxygen reduction, but at the later stage of corrosion, the anodic process began to affect the corrosion rate due to the accumulation of corrosion products. © 2010.
Yi Xie - One of the best experts on this subject based on the ideXlab platform.
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defect rich mos2 ultrathin nanosheets with additional active edge sites for enhanced electrocatalytic hydrogen evolution
Advanced Materials, 2013Co-Authors: Junfeng Xie, Hao Zhang, Ruoxing Wang, Xu Sun, Min Zhou, Jingfang Zhou, Xiong Wen David Lou, Yi XieAbstract:Defect-rich MoS2 ultrathin nanosheets are synthesized on a gram scale for electrocatalytic hydrogen evolution. The novel defect-rich structure introduces additional active edge sites into the MoS2 ultrathin nanosheets, which significantly improves their electrocatalytic performance. Low onset overpotential and small Tafel slope, along with large Cathodic Current Density and excellent durability, are all achieved for the novel hydrogen-evolution-reaction electrocatalyst.