アルミニウム合金のジンケイト前処理におよぼす試料表面調整の効果 [in Japanese] Surface Pretreatment Effects on Zn Deposition in Zincate Process of Aluminum Alloy [in Japanese]
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Surface pretreatment effects of Al and Al-Mg alloy on Zn deposition in the zincate process were evaluated using SEM and XPS. Al surface dissolution in a concentrated NaOH solution followed by zincate treatment produced rapid Zn particles nucleation with uniform size due to Al surface oxide film thinning. The anodic oxidation pretreatment of Al used jointly with electropolishing followed by zincate treatment also resulted in deposition of uniform Zn particles. Anodic oxidation pretreatment without electropolishing, however, resulted in nonuniform Zn deposition indicating that defects in the oxide film could be active sites for Zn nucleation. Al-Mg alloys require both alkaline and acid cleaning in surface pretreatment because Al dissolves in concentrated alkaline solution, and Mg dissolves in acid solution. Magnesium or its enriched compounds on the surface during zincate process in an alkaline zincate solution inhibits Al dissolution and Zn deposition. XPS showed that Zn<sup>2+</sup> remains in the Al oxide layer, which partially charged after Zn stripping in a HNO<sub>3</sub> solution. The role of the first zincate process in double zincate treatment is discussed based on these results.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 48(10), 1019-1024, 1997-10-01
The Surface Finishing Society of Japan