Corrosion-inhibition effect of different phosphate compounds for carbon steel in chloride-contaminated mortars

Abstract

The corrosion-inhibition efficiency of four different phosphates, including aluminum tripolyphosphate (ATP), disodium hydrogen phosphate (DHP), sodium pyrophosphate (SPP), and their mixture (COM), were investigated in Cl--containing mortars. Measurements of the open circuit potential, polarization curve, linear polarization resistance, and electrochemical impedance spectroscopy were performed on carbon steel samples. Furthermore, the morphologies of the corroded rebars were examined after 30 days. The results suggested that corrosion of the rebar in the ATP-containing mortar was suppressed, indicating that the ATP is an efficient corrosion inhibitor.