THE EFFECT OF SURFACE FINISH ON THE EFFICIENCY OF INHIBITORS FOR STEELS CORRODING IN 3% NACL

Abstract

Investigations were carried out to study the effects of surface finish on the efficiency of inhibitors for Steels Corroding in 3 % NaCl. This study was carried out :owing to its importance in the drive towards curtailing the menace of corrosion in industries where varieties of steels are used for production structures, particularly when these structures are Installed offshore. In the course of the study, different grades of steel samples were- polished with emery papers of various grades and then subjected to corrosion study by total immersion technique and electrochemical methods, the corrosion media used was 3% NaCl solultion containing 0.2% of sodium nitrite, sodium nitrate, sodium benzoate or sodium dichromate as inhibitors. The most prominent conclusions drawn from the results were that the inhibition efficiency of te inhibitors generally rose with surface roughness, but fell at a certain critical surface roughness where higher concentration of the inhibitor in use was required and that corrosion of carbon steels in 3% NaCl increased with increase in the carbon content of the steel.