An investigation of the corrosion behavior of Al2O3-based ceramic composite coatings in dilute HCl solution

In this paper, the corrosion behavior of Al2O3–SiO2, Al2O3–TiO2 and Al2O3–SiO2–TiO2 ceramic composite coatings in boiling 1 N HCl solution is investigated. It is shown that the addition of 3% SiO2 to the base spraying powder of Al2O3 increases porosity in the coatings and causes deterioration in their corrosion resistance. Adding 13% TiO2 to Al2O3 improves the anti-corrosion property of the ceramic coating due to a reduction in porosity. The connected porosity in the Al2O3-based ceramic composite coatings rises with the open porosity and is independent of the density of the coating.