Comparative study on corrosion behavior of plasma sprayed Al2O3, ZrO2, Al2O3/ZrO2 and ZrO2/Al2O3 coatings
(1. Department of Mechanical Engineering, Aalim Muhammed Salegh College of Engineering,
Avadi IAF, Chennai 600055, India;
2. School of Mechanical and Building Sciences, VIT University, Vellore 632014, India)
Avadi IAF, Chennai 600055, India;
2. School of Mechanical and Building Sciences, VIT University, Vellore 632014, India)
Abstract: ZrO2, Al2O3, ZrO2/Al2O3 and Al2O3/ZrO2 coatings were fabricated on low carbon steel using atmospheric plasma spraying technique. The microstructure and phase composition of the as-sprayed coatings were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The polarization test, salt spray test and immersion test were used to investigate the corrosion behavior of the coatings in 3.5% NaCl solution. The results suggested that the bilayered Al2O3/ZrO2 coating exhibits superior corrosion resistance when compared with the other coatings. This is ascribed to the presence of very few interconnected pores and stable phases in the coating.
Key words: bilayered coating; Al2O3; ZrO2; atmospheric plasma spraying; corrosion