Combined effect of the exposure angle and face orientation on the atmospheric corrosion behavior of low carbon steel

•Decreasing the angle of exposure increases the rate of corrosion of steel.•RH and rainfall levels are the main factors in the variation of angle corrosion.•Annual corrosion, in low pollution atmospheres, is highest at the ground face.•The EFM technique is complementary to EIS in the analysis of atmospheric corrosion. Tropical atmospheric corrosion in Central America and The Caribbean has been studied preferentially in coastal areas, using samples placed at 30° angles and under ISO 9223 and ISO 8407 standards. Recent studies have shown that the variation of the exposure angle influences the grade of corrosion between both sides of the sample; the side facing up (skyward) and the side facing down (groundward). An evaluation of the annual corrosion at different angles with respect to the horizontal in the San Jose Valley in Costa Rica was carried out, to consider this. The results were analyzed by classical methodologies (gravimetric methods, thickness measurement, XRD and SEM), as well as by electrochemical methods (LPR, EIS and EFM). The values obtained show a decrease in corrosion with increasing angle, as well as differences in corrosion levels between faces. Electrochemical measurements were consistent with each other and with those obtained using classical measurements. [Display omitted]