Corrosion Behaviour Between Al–Zr Alloy Conductor and Cu Transition Terminal via Sc Addition

Abstract

The influence of Sc microalloying on corrosion behaviour between Al–0.2Zr alloys conductor and Cu sheet have been studied in 0.1 M Na2SO4 + 0.05 M NaCl weak acid solution. The observations of corroded morphologies of the Al–0.2Zr alloys conductor were obtained by scanning electron microscopy and transmission electron microscopy. After same short-term service, slight local corrosion and pitting pits occur on the surface of Al–0.2Zr alloy, and corrosion products mainly adhere along grain boundaries of Al–0.2Zr–0.1Sc alloy. After same long-term service, there are many large and saggy corrosion pits on the surface of Al–0.2Zr–0.1Sc alloy, while only some staircase corrosion marks appear on the surface of Al–0.2Zr alloy. Al3Sc and Al3(Zr,Sc) may reduce the electrochemical heterogeneity and the electrochemical reaction of precipitated precipitates on subgrain boundaries and inter-subgrains, thus improving corrosion resistance via Sc addition.