Corrosion Behavior of Spark Plasma Sintered Alumina and Al₂O₃-SiC-CNT Hybrid Nanocomposite

The use of ceramic-based materials has become more common in many applications because of their unique characteristics and properties. Design of alumina hybrid nanocomposites achieved by incorporating two nanoreinforcements, with different morphologies and/or attributes, such as CNTs and SiC, is a new approach that has been adopted to enhance the properties of alumina. The microstructural, mechanical, electrical, and thermal properties of Al₂O₃-SiC-CNT hybrid nanocomposites were investigated and reported in the literature. However, the corrosion behavior was not considered. The present paper reports the electrochemical corrosion behavior of pure Al₂O₃ and Al₂O₃-5SiC2CNT hybrid nanocomposite in acidic (2.34M HCl) and alkaline (6.5M NaOH) environments at room temperature. Ball milling (BM) and spark plasma sintering (SPS) were used for preparation of samples. The microstructure of sintered samples was investigated through field emission scanning electron microscopy (FE-SEM). Potentiodynamic polarization (PDP) technique was used to investigate the corrosion behavior. The corrosion rate of the Al₂O₃-5SiC-2CNT nanocomposite increased 96 and 178% in HCl and NaOH solution, respectively, compared to alumina. Possible corrosion mechanisms and factors effecting corrosion were discussed.