抄録
In this paper, the anodizing of aluminum was investigated using isopropanolamine (1-amino-2-propanol) for comparison with ethanolamine and choline. Studies were conducted to determine the optimum bath compositions for anodizing aluminum in isopropanolamine alkaline baths involving ammonium fluoride and organic acid salts (HCOONH4, CH3COONH4, (NH4)2C2O4, (NH4)2C4H4O6, (NH4)3C6H5O7, (CH2)4(COONH4)2). Uniform films were formed when anodizing in baths containing organic acid salts, but non-uniform films were formed in baths without these additives. The thickest film (about 8μm) was formed in a bath containing ammonium acetate and ammonium tartrate by anodizing for 30min at 20°C with a current density of 1A/dm2. Films formed in baths containing ammonium tartrate or tri-ammonium citrate were the hardest (Marten's scratch hardness test, load 50gf, about 19) while films formed in baths containing tri-ammonium citrate or ammonium adipate showed lower corrosion resistance. SEM observation found that films prepared in baths containing monocarboxylic acids salts had a few pores about 25-40nm in diameter in addition to those with diameters of 15-20nm, while these prepared in baths containing other organic acid salts had pores about with diameters of 30-40nm.
