電解コンデンサ用アルミニウム箔の交流エッチング時の初期ピット形成に及ぼすTiの影響
1999 年 50 巻 9 号 p. 819-823
詳細
1999 年 50 巻 9 号 p. 819-823
Pit initiation and propagation in high-purity aluminum foils during etching with 5Hz rectangular alternating current (AC) in 1mol/dm3 hydrochloric acid solution at 30°C were studied based on potential changes and TEM observation of pit structures. High-purity aluminum foils containing 1 and 6 wt-ppm titanium were used, and titanium effects on pit propagation were discussed. Films stripped from etched foils by immersion in I2/methanol solution and samples prepared by jet electropolishing were used for TEM observation. Cubic pits formed at subgrain boundaries after one AC cycle. Pits varied from hemispherical to cubic during the first anodic half cycle, and a hydrous oxide etch film formed during the next cathodic half cycle. The cyclic voltammogram obtained through polarization in hydrochloric acid solution showed that titanium in high-purity aluminum foil accelerated hydrogen evolution in pits.
