表面技術
Online ISSN : 1884-3409
Print ISSN : 0915-1869
54 巻 , 3 号
選択された号の論文の13件中1~13を表示しています
小特集/新しい表面硬化処理—拡散処理の低温化技術を中心に
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  • 小浦 延幸, 松本 太, 山崎 崇, 猿渡 秀郷, 井手本 康, 北原 しのぶ, 小野 昭二, 内 秀則
    2003 年 54 巻 3 号 p. 217-223
    発行日: 2003年
    公開日: 2004/10/08
    ジャーナル フリー
    Observation of tunnels formed on D. C. etched {100} highly ordered aluminum and analysis of the tunnel shape near the tunnel mouth were performed by using the oxide replica method. The tunnel shape near the tunnel mouth was measured as a function of the tunnel depth (li) for the tunnels obtained by the D. C. etching in HCl, NaCl, AlCl3, HCl+AlCl3, NaCl+AlCl3, H2SO4+AlCl3, and HCl+NaCl aqueous solutions. The tunnel width (Wi) tapered exponentially with li, i. e., log (Wi/Wo)=a·li, where Wo is the tunnel width at the tunnel mouth, in all the solutions examined in this study. In the solutions containing H+ ions, the tunnel width increased with the increase in the tunnel depth near the tunnel mouth at depths of 4 to 5μm from the aluminum surface, followed by a decrease of the tunnel width at depths of 5μm or more. The degree of expansion of the tunnel width increased with increasing H+ concentration. This indicated that the increase of the tunnel width with an increasing tunnel depth near the tunnel mouth was closely related to the presence of H+ ions. Corrosion (Al→Al3++3e-, 2H++2e-→H2) of aluminum near the tunnel mouth, in which H+ took part, was suggested as the origin of the tunnel width expansion near the tunnel mouth. In HCl+AlCl3, NaCl+AlCl3, and H2SO4+AlCl3 aqueous solutions, the degree of expansion of tunnel width decreased rapidly compared to the HCl and AlCl3 solutions. Al3+, Cl-, and H+ ion played an important part in determination of the tunnel shape near the tunnel mouth. The rapid decrease of the degree of the tunnel width expansion near the tunnel mouth was considered to be caused by the increase in the concentration of Al3+, Cl-, and H+ ion in the tunnel, followed by the hindrance of the electrolytic dissolution of Al.
  • 安住 和久, 五百旗頭 敬, 上野 智裕, 瀬尾 眞浩
    2003 年 54 巻 3 号 p. 224-229
    発行日: 2003年
    公開日: 2004/10/08
    ジャーナル フリー
    Resistometry has been applied to the corrosion studies of Fe, Ti and Al electrodes in a thin wire form. Dissolution depth of Fe wire in the active potential range during potential sweep was estimated from resistance data and was consistent with the value obtained from the electric charge. In the passive potential range, the dependence of resistance on growth of the passive film and change in space charge layer of the passive film were observed. For Ti and Al electrodes, resistance changes due to anodic oxide growth were observed. In the high voltage range, however, the temperature of specimens rose due to increase in electric energy loss in the oxide film, and thus the resistivity increased apparently. For Ti electrodes, the growth of the hydride layer was monitored using resistometry under the condition of electrochemical hydrogen loading. For Al electrodes, cathodic dissolution under the condition of hydrogen evolution was measured. In the acidic solution, cathodic passivation phenomenon was observed in which a deposition layer of Al hydroxide suppressed the cathodic reaction.
  • 板垣 昌幸, 四反田 功, 渡辺 邦洋, 小谷野 英勝
    2003 年 54 巻 3 号 p. 230-234
    発行日: 2003年
    公開日: 2004/10/08
    ジャーナル フリー
    Nickel and oil-containing microcapsule composite coatings were fabricated. The oil-containing microcapsules were synthesized by the interfacial polymerization of the oil-soluble and water-soluble monomers. The influences of the intension substance and the surfactant on the size distribution were discussed. The surface and the cross-section of the oil-containing microcapsules composite coatings were observed by scanning electron microscope. From the result of the observation, it was found that microcapsules were involved in the nickel matrix. Furthermore, a new composite plating method, in which the 100% of the microcapsules in the electrolyte solution were incorporated into the nickel matrix, was developed. In addition, the stability of microcapsules in the nickel matrix was investigated. It was confirmed that microcapsules in the nickel matrix were stable.
  • 渡辺 恵司, 坂入 正敏, 高橋 英明, 平井 伸治
    2003 年 54 巻 3 号 p. 235-240
    発行日: 2003年
    公開日: 2004/10/08
    ジャーナル フリー
    Aluminum specimens were covered with SiO2 film by a sol-gel coating and then anodized galvanostatically in a boric acid solution. Time variations in the anode potential during anodizing were monitored, and the structure and dielectric properties of anodic oxide films were examined by TEM-EDX, and electrochemical impedance measurements. It was found that anodizing of aluminum coated with SiO2 films leads to the formation of anodic oxide films that consist of an outer Al-Si composite oxide layer and an inner Al2O3 layer at the interface between the SiO2 film and the metal substrate. The breakdown potential of anodic oxide films formed on specimens with SiO2-coating was about 100 V higher than that without SiO2 coating. The capacitance of specimens after sol-gel coating and anodizing was slightly higher than that without sol-gel coating. In the film formation mechanism, the conversion of Al2O3 into Al-Si composite oxide at the interface between the inner and outer layers is discussed in terms of inward transport of Si-bearing anions across the outer layer.
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