バリアー型アルミニウム陽極酸化皮膜中のホウ素の濃度と分布 Content and Distribution of Boron in a Barrier Type Anodic Oxide Film on Aluminum
In anodization of alminum, electrolyte anions are incorporated into the oxide film from the liquid electrolyte. The anion distribution is related to physical and chemical properties and the mode of film formation. Prompt Gamma-ray Analysis (PGA) has higt sensitivity (2000cps·mg<sup>-1</sup>) and a low detection limit (0.002μg) for boron, so it is applicable to the determination of boron in aluminum oxide films.<br>It was found that the average boron content was 0.25wt% with electrolysis at 25°C in a 0.5mol·dm<sup>-3</sup> H<sub>3</sub>BO<sub>3</sub>-0.05mol·dm<sup>-3</sup> Na<sub>2</sub>B<sub>4</sub>O<sub>7</sub> solution. Differences of the electrolytes and in formation voltages, i.e. in the thickness of the barrier films, had little effect on this value, but it varied in proportion to the boron concentration in the electrolyte and decreased at higher temperatures.<br>Boron was distributed to a distance of half the depth from the surface, and was not detected near the oxide/metal interface. This result can be explained on the basis of the transport number (0.45-0.6) of Al(III) ion and by the absorption of borate ions into hydrous aluminum oxides.
- 表面技術 = The Journal of the Surface Finishing Society of Japan
表面技術 = The Journal of the Surface Finishing Society of Japan 47(5), 456-460, 1996-05
The Surface Finishing Society of Japan