Protective performance evaluation of AT13 ceramic coatings sealed with organic and inorganic sealants in chloride-containing solutions at different temperatures

Abstract

Exploring the sealing stability of different media to plasma-sprayed refractory Al2O3–13%TiO2 ceramic coatings is of guiding significance for rational application. Thus, the protective performance of commonly used organic and inorganic sealing agents under different environmental temperatures in chloride ion-containing solutions was investigated in this paper. Firstly, the corrosion resistance of each sample at different temperatures was characterized by potentiodynamic polarization studies. Then the effect of solution temperature was analyzed by Arrhenius equation. Moreover, the mechanism of solution temperature influence was discussed via electrochemical impedance spectroscopy, aiming to provide guidance on the selection of sealing agent types for different environments. The results indicated that both sealing agents provided corrosion resistance far beyond that of the as-sprayed coating at different temperatures. However, as the temperature increased, despite the stable behavior of the inorganic sealing coating itself, the organic sealing agent exhibited a more stable application effect in corrosion resistance, even at 80 °C, it can still show a corrosion current density in the order of 10−8 A cm−2.