evaluation of corrosion behavior of al2o3/mgo/tio2 mixed metal oxides coating synthesized by sol-gel method in chloride solution

in this study, mixed metal oxides al2o3/mgo/tio2 coatings with al/mg/ti ratio of 5:1:3 and 2.5:3:4 were coated on aluminum by sol-gel method. the surface morphology, phase analysis, thermal behavior and the corrosion behavior of the al2o3/mgo/tio2 coatings were characterized by (sem), (xrd), (tg-dta) and potentiodynamic polarization test in 3.5 wt.% nacl solution. the results demonstrated that heat treatment at 450 °c caused the decrease of corrosion resistance of coating so that after heat treatment, corrosion rate of the samples coated with al/mg/ti molar ratio of 5:1:3 and 2.5:3:4 were 5 and 13 times respectively.