Corrosion Inhibition and Inhibition Mechanism of a Modified HPAM to Q235 Steel in 3.5% NaCl Solution

A series of modified hydrolyzed acrylamide (HPAM) were synthesized with functional monomers and HPAM. The viscosity average molecular weight and apparent viscosity of this kind of modified HPAM were measured, and its structure was characterized. The corrosion inhibition of modified HPAM to Q235 steel in 3.5% NaCl solution was studied through corrosion immersion test and electrochemical test. The results show that the modified HPAM with viscosity average molecular weight of 13 million had the best corrosion inhibition performance at 40 ℃. The inhibition efficiency increased with increase of modified HPAM concentration. When the concentration of modified HPAM was 500 mg/L, the inhibition efficiency reached 85.16%. The modified HPAM was a mixed type corrosion inhibitor that mainly controlled the anode. After adding modified HPAM, the electrode process changed from activation control to concentration control. The adsorption way of the modified HPAM on surface of Q235 steel was chemical adsorption, and it conformed to the Langmiur isotherm adsorption model.