Effect of Superheat Temperature on the Microstructure and Corrosion Behavior of Al-Zn-In Sacrificial Anode Produced by Semi-Solid Cooling Slope Casting

In this study, the effect of superheat temperature of cooling slope process on the microstructure and electrochemical behavior of Al-Zn-In sacrificial anode has been investigated. Cooling slope Semisolid Casting was performed at three different temperatures of 660, 680, and 700 °C and the microstructure investigated by optical microscopy, electron microscopy and image analysis software. The electrochemical behavior of the alloy was determined by electrochemical impedance and polarization tests. According to the results, the sample produced by cooling slope at a temperature of 680 °C with a sphericity number of 0.68 and grain size of 45 microns had the maximum sphericity and minimum grain size. Also, the mentioned sample had the corrosion rate of 0.086 mm/year, which was the highest corrosion rate compared to other samples, and the results of the electrochemical impedance test confirmed the better behavior of its. Increasing the superheat temperature to 700 °C has led to a decrease in the electrochemical and microstructural properties of the sample.