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Stuttgart Mühlhausen, Germany

Yu Y.D.,China Jiliang University | Cao Y.,China Jiliang University | Li M.G.,China Jiliang University | Wei G.Y.,China Jiliang University | Dettinger H.,ZEH Metallveredelungs GmbH
Materials Research Innovations

Magnetic fields parallel to electrodes were introduced during plating process to obtain ZnNi alloy films from acid baths. Effects of different magnetic intensities on the composition, nucleation magnetism, surface morphology and anticorrosion of ZnNi films were investigated. With the increase in magnetic intensity, deposition rate and nickel contents increased gradually due to magnetohydrodynamic (MHD) effects caused by Lorentz force. It was found that magnetic force Fm in the magnetic electrodeposition process could have a significant effect on the mass transfer to dramatically improve deposition rate. Maximum deposition rate (90 m h-1) was achieved when the magnetic intensity was equal to 1 T. The films were densely covered with typical nodular structure. Films of smaller grain size and smooth surface could be formed under high magnetic intensity as a result of Lorentz force and MHD effects. Moreover, ZnNi films obtained with higher magnetic intensity possessed more positive self-corrosion potential and optimal anticorrosion performance. However, much higher nickel contents in ZnNi films may drop anticorrosion performance. © W. S. Maney & Son Ltd. 2014. Source

Zhou H.R.,China Jiliang University | Wei G.Y.,China Jiliang University | Lou J.W.,China Jiliang University | Cao Y.,China Jiliang University | And 4 more authors.
Surface Engineering

FePt magnetic multilayers were pulse electrodeposited from the mixture of ammonium hexachloroplatinate and iron dichloride in ionic liquids based on glycol (EG) and 1-ethyl-3-methylimidazolium chloride (EMIC). The chelate effect and electrochemical behaviour of the EMIC with the ions were determined by ultraviolet-visible spectra and cyclic voltammetry respectively. The iron atomic content in the FePt films ranged from 0.4 to 81.0 at-% when deposition potentials changed from 1.0 to 22.0 V(Ag/AgCl) in electrodeposition system with the EG (50 mL), ammonium hexachloroplatinate (25 mM L-1), iron dichloride (175 mM L-1) and EMIC (25 mM L-1) at 393 K. Fe50Pt50 thin films with smooth surface (50 at-% iron layer in FePt film) and the multilayer cross-section were obtained. Fct structural FePt multilayer was obtained based on X-ray diffraction pattern. Magnetic hysteresis loops showed that the multilayer possessed a magnetic anisotropic behaviour. © 2013 Institute of Materials, Minerals and Mining. Source

Zhou H.,China Jiliang University | Wei G.,China Jiliang University | Li M.,China Jiliang University | Wang J.,China Jiliang University | And 5 more authors.
Journal of the Electrochemical Society

This work concerns the Fe50Pt50/Fe2Pt 98 magnetic multilayers electrodeposited from ionic liquid system. Iron concentration in the Fe-Pt films was ranging from 1.65 at% to 76.45 at% when the deposition potentials were changed from -1.0 V to -2.2 V vs Ag/AgCl in electrodeposition system at 353 K. Fe50Pt50/Fe 2Pt98 multilayers were successfully electrodeposited from the ionic liquid system at 353 K by controlling the pulse electrodeposition potential. Current transients revealed that the nucleation of Fe 50Pt50 layer was a three-dimensional instantaneous nucleation growth controlled by diffusion. Fe50Pt50/ Fe2Pt98 multilayers of four-bilayer structure (FBS) were prepared with single-bath technique using pulse electrodeposition under potential control. The cross-sectional images of multilayers showed distinct layers with columnar structure. X-ray diffraction (XRD) pattern showed that the fct structure of Fe50Pt50/Fe2Pt98 multilayer had been obtained. Magnetic hysteresis loops showed that perpendicular coercivity values were increased from 153 Oe to 800 Oe with the increase of Fe50Pt50 layer thickness in FBS from 118 nm to 300 nm. FBS exhibited a magnetic anisotropic behavior. © 2013 The Electrochemical Society. All rights reserved. Source

Wei G.,China Jiliang University | Zhou H.,China Jiliang University | Ge H.,China Jiliang University | Ge H.,National Center for Quality Supervision and Testing of Magnetic Materials and Products | Dettinger H.,ZEH Metallveredelungs GmbH
Surface Engineering

This work concerns FePt nanowires electrodeposited from electrolyte of E1 [ammonium hexachloroplatinate (25 mM L-1), 1-ethyl-3-methylimidazolium chloride (25 mM L-1)], iron dichloride (315 mM L-1) and glycol (50 mL) at 393 K. FePt nanowires and films were electrodeposited by controlling the electrodeposited time under suitable potential in E1. FePt nanowires were prepared at different times of 600, 800 and 1000 s when deposition potential was 2.0 V versus Ag/AgCl. The SEM patterns proved that FePt nanowires were prepared at suitable deposition time (600-1000 s). The X-ray diffraction pattern indicated that the face centre tetragonal structure of FePt nanowires was obtained. Magnetic hysteresis loops showed that aggregation could decrease the coercivity, and some nanowires were larger than the mean diameter, which exhibited a comparatively large ferromagnetic behaviour. © 2016 Institute of Materials, Minerals and Mining. Source

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