有機アルカリ性浴(ベンジルアミン-フッ化物基液)中でのアルミニウムの陽極酸化における有機酸塩添加の効果 [in Japanese] Effect of Organic Acid Salts on the Anodizing of Aluminum in Organic Alkaline Baths(Benzylamine-Fluoride Base) [in Japanese]
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In this paper, the anodizing of aluminum was investigated using water-soluble aromatic amine (benzylamine) to compare with aliphatic amine. Investigations were conducted to determine optimum bath compositions for the anodizing of aluminum in organic alkaline baths (benzylamine-fluoride base) involving ammonium fluoride and organic acid salts (HCOONH<sub>4</sub>, CH<sub>3</sub>COONH<sub>4</sub>, (NH<sub>4</sub>)<sub>2</sub>C<sub>2</sub>O<sub>4</sub>, (NH<sub>4</sub>)<sub>2</sub>C<sub>4</sub>H<sub>4</sub>O<sub>6</sub>, (NH<sub>4</sub>)<sub>3</sub>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>). In the case of anodizing in baths containing organic acid salts, uniform films were formed, but non-uniform films were formed in baths without these additives. The thickest film (about 8μm) was formed in a 0.05mol/L benzylamine bath containing 0.1mol/L ammonium fluoride and 0.3mol/L ammonium acetate or in a 0.2mol/L benzylamine bath containing 0.1lmol/L ammonium fluoride and 0.2mol/L ammonium tartrate by anodizing for 30min at 20°C with a current density of 1A/dm<sup>2</sup>. The film formed in the 0.2mol/L benzylamine bath containing 0.1mol/L ammonium fluoride and 0.1mol/L ammonium tartrate was the hardest (Marten's scratch hardness test, load 50gf, about 13) and the film formed in 0.1mol/L benzylamine bath containing 0.1mol/L ammonium fluoride and 0.1mol/L ammonium citrate showed the highest corrosion resistance. SEM observation found that pores of films prepared in back containing ammonium acetate were about 30∼50nm in diameter, while these prepared in baths containing other organic acid salts were about 50nm.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 47(1), 67-73, 1996-01
The Surface Finishing Society of Japan