Improvement in Corrosion Inhibition Efficiency of Molybdate-Based Inhibitors via Addition of Nitroethane and Zinc in Stimulated Cooling Water

Abstract EN

An investigation was conducted to improve the corrosion inhibition efficiency of molybdate-based inhibitors for mild steel which is the main construction material of cooling water systems, using nitroethane as an organic compound beside zinc.

In this study a new molybdate-based inhibitor was introduced with the composition of 60 ppm molybdate, 20 ppm nitrite, 20 ppm nitroethane, and 10 ppm zinc.

Inhibition efficiency of molybdate alone and with nitrite, nitroethane, and zinc on the uniform corrosion of mild steel in stimulated cooling water (SCW) was assessed by electrochemical techniques such as potentiodynamic polarization and electrochemical impedance (AC impedance) measurements.

Weight loss measurements were made with coupon testing specimens in the room temperature for 48 h.

Studies of electron microscopy, including scanning electron microscopy (SEM) photograph and X-ray energy dispersive spectrometry (EDS) microanalysis, were used.

The results obtained from the polarization and AC impedance curves were in agreement with those from the corrosion weight loss results.

The results indicate that the new inhibitor is as effective as molybdate alone, though at one-ninth of the concentration range of molybdate, which is economically favorable.