Fe Content In Deposit Research Articles

Experiment on Electroforming Ni-Fe Property for Micro Fabrication

The relationship between the composition, coating microstructure and electromagnetic properties of electroforming Ni-Fe alloys was studied in this paper. And the optimal process parameters to obtain Ni-20%Fe deposition was as following: FeSO4•7H20 concentration was 6 g/L; PH value of the solution was 2.5; current density was 3.5 A/dm2; electrolyte temperature 55 °C. The results indicate that the Ni-Fe deposit is bright and compact, the crystal-planes of the plating were (111), (220) and (200). Electrodeposited Ni-20%Fe has a strong paramagnetism effect with the smallest remanence of 0.5 emu, The coercivity show a monotonic decrease with increasing Fe content in deposit, which proved that the electroformed Ni-20%Fe alloy has good electromagnetic property and could be used in MEMS actuator manufacturing.

Relationship of Fe 2+ concentration in solution and current efficiency in electrodeposition of CoFe films

Our published work on stress evolution in CoFe films [Electrochim. Acta 55 (2010) 9035], indicated that adsorption/desorption of hydrogen is a primary cause of tensile stress which increases with the increase of Fe-content in deposit and decrease of current efficiency, i.e. higher supply of protons to the electrode surface. Using the electroanalytical techniques in this study it has been demonstrated that a higher supply of protons to the electrode surface with increase of Fe 2+ concentrations in solution brings about higher Fe-content in deposit and lower current efficiency. First, it was found that the reduction rate of H + from the solution is faster on CoFe surface with higher Fe-content in CoFe deposit. Second, it was found that higher concentrations of Fe 2+ in solution bring about higher surface concentration of H + through the Fe 2+ hydrolysis reaction, i.e. Fe 2+ + HOH = FeOH + + H +. The proton liberated through hydrolysis reaction is reduced as soon as it is formed, together with other electroactive species.

Electrodeposition of Ferromagnetic Metal Nanowires

Ni-Fe alloy films and nanowires were fabricated using electrodeposition technique. The cylindrical shape of nanowires was precisely transferred from the nanochannels of membrane filters and the aspect ratio reached to around 60. Coercive force in in-plan direction of Ni-Fe alloy films decreased to ca. 1 Oe with increasing Fe content in deposits while, in perpendicular direction, the films were hardly magnetized. Magnetic hysteresis loops revealed that the nanowires were spontaneously magnetized to the long axis direction and the coercive force reached to ca. 200 Oe.

Ｆｅイオン共存下での電気Ｚｎめっきにおける不純物の共析挙動

The codeposition behavior of impurity Fe with Zn was investigated galvanostatically over the current density range from 1 to 1000 A/m2 at 40°C in zinc sulfate solution of pH 3 containing 5000 ppm of Fe2+ and the other organic or inorganic impurity. Fe hardly codeposited with Zn in the solution containing both Fe and Mo or Ni as impurity. The codeposition of Fe seems to be strongly suppressed in the presence of Zn2+ ions due to the adsorption of Zn hydroxide preferentially formed on the cathode. However, in the solution containing Fe and Cu, Fe evidently codeposited with Zn. The Fe content in deposit decreased with increasing the current density. The role of codeposited Cu is considered to promote Fe deposition by providing an active sites free from adsorbed Zn hydroxide. On the other hand, in the solution containing Fe and stearyle benzyl ammonium chloride (C18-Benzyl) as impurities, the codeposition of Fe was significantly recognized. The cathode potential for Zn deposition was greatly polarized by addition of C18-Benzyl and the Fe content in deposit increased with increasing the current density.

Codeposition Behavior of Impurities during Electrogalvanization in Sulfate Baths in the Presence of Fe Ions

The codeposition behavior of impurity Fe with Zn was investigated galvanostatically over the current density range 1–1000 A/m2 at 40°C in zinc sulfate solutions of pH 3 containing 5000 ppm of Fe2+ and other organic or inorganic impurities. Fe showed hardly any codeposition with Zn in solutions containing Fe and either Mo or Ni as impurities. The codeposition of Fe is strongly suppressed in the presence of Zn2+ ions through preferential adsorption of Zn hydroxide on the cathode. In solutions containing Fe and Cu, Fe codeposited with Zn and the Fe content in the deposit decreased with increasing current density. Codeposited Cu promotes Fe deposition by providing active sites that are free of adsorbed Zn hydroxide. In solutions containing Fe and benzyl(dimethyl)(stearyl)ammonium chloride (C18-Benzyl) as an impurity, significant amounts of Fe were codeposited. The cathode potential for Zn deposition was greatly polarized by addition of C18-Benzyl, and the Fe content in deposits increased with increasing current density.

電気Znめっき鋼板と電気Zn-Fe合金めっき鋼板の塗膜下腐食挙動

Investigated was corrosion behavior of Zn and Zn-Fe alloy electroplated steel sheets under paint film in atmospheric exposure test and modified Volvo test (atmospheric exposure test with 5mass%NaCl solution sprinkling). 1) Creepage width of paint film remained small in the range below 14mass% Fe, and increased with Fe content in deposit in the range above 20mass%Fe in atmospheric exposure test, though it exhibited minimum value at 15mass%Fe in modified Volvo test. 2) The creepage width in both outdoor exposure test and modified Volvo test showed correspondence to corrosion current density of unpainted specimens exposed to each test in the range below 30mass%Fe, indicating that corrosion under paint film is predominantly determined by corrosion rate of the deposit with corrosion products formed in corrosion test. 3) It was considered that wedge effect of iron rust resulting from volume expansion additionally affected the corrosion in the range above 30 mass%Fe. 4) Furthermore, corrosion reaction under paint film was discussed on the basis of EPMA analysis.