Corrosion of steel in lithium bromide solution containing inhibitor

Abstract

The corrosion behaviour of carbon steel in 55% lithium bromide solution containing a complex organophosphonate–molybdate inhibitor has been studied using weight loss tests, electrochemical measurements, SEM and X-ray photoelectron spectroscopy. The results showed that the species provides an excellent inhibition performance in 55% lithium bromide solution. When its concentration reached 0·8 kg m⁻³ in 55% lithium bromide+0·07 mol dm⁻³ lithium hydroxide at 240°C, the carbon steel's corrosion rate decreased to 25·02 μm/year, and the anodic passivation region and the passive current density of carbon steel were ∼700 mV and 1 μA cm⁻² respectively. At the same time, the capacitance value of electric double layer decreased, and the charge transfer resistance increased. The compact compound film formed on the surface of carbon steel in the inhibited LiBr solution was mainly composed of iron oxide and molybdenum oxide.