Abstract
The role of surface finish of carbon steel samples subjected to different degrees of surface finish (as received, ground, and ground and corroded), on the performance of sodium nitrite inhibitor (100, 400, and 800 ppm), at temperatures (22±2 °C) and (70±2 °C) was assessed using different electrochemical test techniques.
Rough ground samples (100 grit paper), showed pronounced corrosion attack (low Rp). The severity of corrosion attack was more pronounced when tests were conducted in aqueous solution containing low concentration of inhibitor (100 ppm). In contrast, low to/no corrosion attack (high Rp/ inhibitor efficiency) was observed when carbon steel samples were subjected to soft grinding using 1000 grit paper. This was observed even when tests were conducted at inhibitor concentrations as low as (100 ppm).
Marked decrease in the inhibitor efficiency was recorded for ground and corroded carbon steel samples even when samples were ground at 1000 grit paper.
Generally, tests at high temperature of (70 ± 2 °C) observed to reduce the inhibitor efficiency.