Journal of The Surface Finishing Society of Japan
Online ISSN : 1884-3409
Print ISSN : 0915-1869
ISSN-L : 0915-1869
Volume 57, Issue 11
Displaying 1-9 of 9 articles from this issue
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  • Naoto TAKANE, Hiroshi NARITA, Satoshi NAGAYA
    2006 Volume 57 Issue 11 Pages 784
    Published: 2006
    Released on J-STAGE: June 05, 2007
    JOURNAL FREE ACCESS
    The nickel phosphorus alloy multilayer film was made by using both electroplating and electroless plating together from a single bath including phosphinic acid and nickel sulfate. The compositions of the nickel phosphorus alloy made by electroplating and by electroless plating from the same bath were different under suitable plating conditions. The multilayer film was made on a copper substrate by alternate continuous electroplating and electroless plating from that single bath. After bending that film with copper substrate in the liquid nitrogen to break the film and make the cross section, the film was examined. An SEM and EPMA examination of the cross section confirmed that the film was a multilayer of two kinds of nickel phosphorus alloys, and the phosphorus density of each layer was different. In addition, it was confirmed by XRD that the multilayer consisted of two types of layers, a crystalline one and an amorphous one. According to the observation of the structure of the cross section by SEM, it seems very likely that the strength of each layer was different.
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  • Makoto YUASA, Nobuyuki MOMOZAWA, Kenichi OYAIZU, Yutaka OHTANI, Kenji ...
    2006 Volume 57 Issue 11 Pages 789
    Published: 2006
    Released on J-STAGE: June 05, 2007
    JOURNAL FREE ACCESS
    Methods for prediction of gold plating characteristics by numerical analysis were investigated. The gold plating bath for the evaluation contains 5,5-dimethylhydantoin (DMH) as the complexing agent. HAuCl4 was used as the gold source, and phosphate salt was contained as a pH buffer. Thallium ion was added to refine the deposited grains. The concentration of Au([Au]), the pH, and the temperature were manipulated to determine the composition and conditions of the plating bath. The appearance of gold films was evaluated by color measurement using the L*a*b* color system. This method of evaluation is advantageous in terms of quantification of the appearance. Values of the color measurement tended to change depending on the various compositions and conditions of the plating bath. The brightness of the color L* obtained as a result of the color measurement was analyzed numerically with a statistical technique. The following experimental formulas were established by the numerical analysis.
    L*(−) = K0{1−exp(−K1C)}−K2C
    K0(−) = 73.9−2180exp(−0.125T)
    K1(M1) = 178
    K2(M1) = 338−323exp[−{(pH−7.18)/1.17}2]
    [C : [Au] (M = mol/dm3), T : temperature(ºC)]
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  • Norio NAKAMURA, Kazuharu SOBUE, Hachiro IMAI
    2006 Volume 57 Issue 11 Pages 793
    Published: 2006
    Released on J-STAGE: June 05, 2007
    JOURNAL FREE ACCESS
    The change in the chemical composition of the corrosion product on steel can be identified with in-situ Raman spectroscopy while the steel is polarized in a solution. In this paper, we tried to clarify the corrosion process of the steel for gas pipelines.
    γ-FeOOH and Fe3O4 were detected with the Raman spectra measured in the 100mg/dm3Cl solution holding at −0.3V vs.Ag/AgCl. The coexistence of γ-FeOOH and Fe3O4 was confirmed from the Raman spectrum measured in the corrosion test. It is considered that Fe3O4 was formed via the reduction as follows:
    Fe2+ + 8FeOOH + 2e → 3Fe3O4 + 4H2O
    In the early stage of corrosion, γ-FeOOH was detected from Raman spectra measured in the 1000mg/dm3HCO3 solution holding at 0.5V vs. Ag/AgCl. However, the peak of γ-FeOOH disappeared from the Raman spectra measured in the corrosion test after the middle stage of corrosion. It is conceivable that the γ-FeOOH disappeared or that the surface was covered with corrosion products inert to Raman measurement.
    We were able to investigate the corrosion process of the steel for gas pipelines with in-situ Raman spectroscopy while it was polarized in a solution.
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