Corrosion Rate Comparison Between a ZnCrO4 Coating and a Mixture of Epoxy Plus PU Coating on HSLA ASTM a 1011 Gr50 Steel Exposed to a Saline Spray Corrosion Chamber

The A corrosion rate comparison between StopMate ZnCrO4 coating and a mixture of Hempadur Mastic 45881 epoxy plus Hempathane Topcoat 55210 PU coating on HSLA ASTM A 1011 Gr50 steel exposed to a saline spray corrosion chamber at 5% was studied. Two surface cleaning methods were also utilized, SSPC-SP 3 that consisted in a mechanical process complemented with an electric tool cleaning and SSPC-SP 5 by blasting. Steel samples of 50 × 50 × 2 mm were separated in different groups to apply coatings, including base material without any previous preparation, and were introduced inside a saline spray corrosion chamber for 200, 280, 380 and 480 h. Corrosion rate was calculated following the ASTM G1 standard and visual inspection evaluated the corrosion grade and blistering frequency on the steel surface according ASTM D610 and ASTM D714 standards, respectively. A scanning electron microscope was utilized to measure the layer thickness of each coating and it was also let analyzing the steel microstructure.