Control of Corrosion Rate of Metal Alloys: SS 304 And SS 201 Using Phosphate Inhibitor in Nacl 3.5%

Abstract

Corrosion is metal damage caused by electrochemical reactions with its environment. This environment can be water, air, gas, acid solution, salt solution, and others. Metals are highly active in producing an oxide layer on the metal surface under the influence of an aerobic environment. Metal corrosion is a process where the action of the surrounding media damages metal materials by the introduction of corrosion ions. This study aims to determine the best conditions for phosphate in controlling the rate of corrosion and Knowing the inhibition of phosphate on controlling the rate of corrosion. The materials used were stainless steel 201, stainless steel 304, and phosphate as an inhibitor. Meanwhile the solution NaCl 3.5% as a corrosive media environment and distilled water. Based on this research, the best phosphate concentration in reducing the corrosion rate of stainless steel 201 and 304 is 100 ppm with a reduction in the corrosion rate of stainless steel 201 of 0.022312 mpy with an inhibition percentage of 89.68%, and a reduction in the corrosion rate of stainless steel 304 by 0.045694 mpy with the percentage of inhibition is 94.027%. The corrosion rate of 304 stainless steel is lower than that of 201 stainless steel caused by differences in the Cr element composition of each metal. Stainless steel 304 contains 18.24% Cr while stainless steel 201 contains 13.00% Cr. The lower the Cr content in stainless steel, the stainless steel will be more susceptible to corrosion.