Microstructure and Corrosion Mechanism of ACSR Conductor in Dry/Wet NaCl Salt Atmosphere

Dry/wet NaCl salt spray experiment was employed to study the phase composition of corrosion products,microstructure of corrosion layers and corrosion mechanism of the aluminium conductor steel reinforced (ACSR).The results showed that the corrosion of the ACSR conductor was a combined mechanisms of pitting corrosion,crevice corrosion,galvanic corrosion and etc.The phase composition of the corrosion layer was complicated and mainly included hydroxides and basic chlorides of Zn and Al.The pits appeared firstly and then continuous corrosion layers formed around the Al strands and the galvanized Zn layer.The corrosion layers were non-uniform and generally composed of dense inner layers and porous outer layers.In the early stage of the corrosion (≤168 h),the corrosion of the external Al strands was stronger than that of the internal,however,it reversed in the later stage (>168 h).The corrosion rate of the galvanized Zn layer was the most intense.After 480 h,the galvanized Zn layer was completely destroyed and gradually lost the protection effet to the steel core strands.