Effects of time and temperature on the mild steel corrosion inhibition by molybdate and nitrite

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-fareast-font-family:"dejavu="" sans";="" mso-bidi-font-family:mangal;mso-bidi-theme-font:minor-bidi;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">An investigation has been conducted to find out the effect of soaking time and temperature on the Corrosion inhibition of mild steel by sodium molybdate and sodium nitrite in simulated cooling water (SCW). Increase of soaking time increases corrosion rate of the mild steel in SCW. However, when sodium molybdate and sodium nitrite are present corrosion rate decreases or per cent inhibition efficiency (% IE) increases with the soaking time. High concentration of inhibitors or stirring of the solution results in the attainment of the corrosion rate to the constant low value at a short soaking period. Molybdate loses its inhibition capacity comparatively rapidly than nitrite with the rise of temperature, and none of them alone is effective at the increased temperature of SCW. When these two inhibitors are used combinedly effective corrosion inhibition of mild steel is obtained up to 55°C temperature of SCW.</span>