Studying of Corrosion inhibition on Low Carbon Steel by Aqueous Solution Diammonium Phosphate Fertilizer Solution

Abstract

The aim of the present work is study the corrosion behavior of low carbon steel in aqueous diammonium phosphate (DAP) fertilizer solution with and without inhibitors’ addition in different concentrations (5% & 35%) in different temperatures (25, 35, and 50 °C) by using polarization method and take an optical microscope with ( 600 X ) for samples after testing. The inhibitors used in this work are thiourea 20 ppm in concentration, and( 20ppm thiourea + 20ppm hexamine ) in concentration.The results show that the adding of the thiourea (20 ppm in 5% and 35% DAP solution respectively)causes increasing the inhibition efficiency to 63% and 60% at room temperature(25 °C), but at 50 °C it is be 35% and 32% . Also the results improve that the current density decreases while inhibition efficiency for both hexamine and thiourea (in 5% and 35% DAP solution respectively) be 70% and 75% at room temperature and 62% and 64% at 50°C respectively.