Improving the corrosion resistance of a thin aluminum film by surface treatment using 1, 2-Bis(triethoxysilyl)ethane(BTSE), Bis(triethoxysilyl)propyl)tetrasulfide(BTSPS), and Bis(trimethoxysilylpropyl)amine(BTSPA)was evaluated. A thin silane coupling layer of BTSE or BTSPS was formed on the film by immersion in a BTSE-ethanol or BTSPS-ethanol solution, thereby markedly improving both the general and pitting corrosion resistance of the film. The pitting potential shifts to the noble side. The quantity of the silane coupling molecule regarding BTSE or BTSPS increases markedly with the dipping time. These behaviors might be explained by the hard and soft acid-base(HSAB) principle. However, the corrosion resistance of the Al film immersed in BTSPA decreases because the formation of corrosion resistance deteriorates, producing a crude thick film. Clarifying the mechanism by which the corrosion-resistant improvement is affected by the silane coupling treatment requires elucidation of the chemical properties of the silane coupling layer: not only the silane coupling layer moldability based on the HSAB principle, but also the ion permeability.

View full abstract

This study investigated the effect of current density and concentration of bis(3-sulfopropyl)disulfidedisodium(SPS)upon the residual stress of copper sulfate plating. The residual stress increased because of increasing lattice strain with current density. Moreover, the lattice strain increased with hydrogen entrapped in the grain boundary of Cu films. Results clarified that residual stress was suppressed concomitantly with increased SPS concentration. During self-annealing of small grains, the residual stress is reduced by electrodeposition of a high concentration of SPS.

View full abstract

This study elucidated electrochemical behaviors of an IrO₂-Ta₂O₅/Ti anode and pre-deposited PbO₂ layers of two types on IrO₂-Ta₂O₅/Ti anodes in H₂SO₄ solutions. The onset potential for the reduction of β-PbO₂ of a pre-deposited PbO₂ layer prepared from acidic solutions was more positive than the oxygen evolution potential on the IrO₂-Ta₂O₅/Ti anode. Formation of a non-conductive PbSO₄ film on IrO₂- Ta₂O₅/Ti anodes in copper foil production can be attributed to the formation of a local cell consisting of a PbO₂ cathode and an IrO₂-Ta₂O₅ anode during an open-circuit condition.

View full abstract