Abstract
The filiform corrosion resistance of the sanded surface of aluminum alloy was studied in accelerated corrosion test. It was found that the rougher the sanding paper, the poorer the filiform corrosion resistance, and the stronger the sanding intensity, the poorer the filiform corrosion resistance. The fact that phosphated specimens performed much better than the unphosphated one shows that the phosphate coating is a important factor to obtain high filiform corrosion resistance. Phosphate coating was nonuniform on the sanded surface with few phosphate crystals deposited on the sanding scratch. Filiform corrosion tended to follow the sanding scratch and chloride was detected along it. The nonuniformity of phosphate coating was considered as a result of the nonuniformity of oxide.
