有機アルカリ性浴 (ヒドラジンーフッ化物基液) 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

抄録

Bath compositions suitable for the anodizing of aluminum were investigated in organic alkaline baths (hydrazinefluoride base) with additions of ammonium fluoride and organic acid salts In baths containing organic acid salts (CH₃COONH₄, (NH₄)₂C₂O₄, (NH₄)₂C₄H₄O₆ or (NH₄)₃C₆H₅O₇), uniform films were formed but in baths without these additives the films were not uniform The films that were thickest (about 15μm) and hardest (about 23 as Marten's scratch hardness under load of 50gf) were obtained in a 0.1mol/L hydrazine bath containing 0.1mol/L ammonium fluoride and 0.05mol/L ammonium citrate by anodizing for 30min at 20°C with a constant current density of 2A/dm² SEM observation of the film surface showed that the films formed in baths containing ammonium oxalate or ammonium citrate had larger pores (500∼1000Å) than those formed in baths containing ammonium acetate or ammonium tartrate. It is concluded that the formation of large pores is caused by the dissolution of cell walls at higher voltages (about 110V)