Anti-Corrosion Coatings Based on Nb2O5 - a Comparison Between two Coatings Technology: Thermal Spray Coating and Epoxy Paint

Abstract

Niobium pentoxide (Nb2O5) has gained prominence as an anti-corrosive pigment. The performance of anti-corrosive coatings based on Nb2O5 was tested in an environment with an acid atmosphere and at high temperatures. For comparison, SAE 1020 carbon steel samples were coated with two anti-corrosive coatings based on Nb2O5: applied by thermal spray and epoxy paint. The samples were partially immersed in the laboratory for 720 h and 1440 h in a 40% (v/v) H2SO4 at 25°C, 60°C, and 80°C. An in-situ evaluation was carried out of chemical industry installations over 4383 h in microclimates with the presence of corrosive agents at temperatures up to 70°C. The results obtained showed that the Nb2O5 coatings applied by thermal spray offer better anti-corrosive performance under immersive conditions. In contrast, under conditions submitted to steam, both the Nb2O5 coatings applied by thermal spraying and epoxy-Nb2O5 paint show excellent anti-corrosive behavior.