Effect of organic montmorillonite on the performance of modified waterborne potassium silicate zinc-rich anti-corrosion coating

Abstract

In this work, montmorillonite (MMT), as an anti-settling agent, was added to modified waterborne potassium silicate zinc-rich coating (MWPC), aiming at improving its anti-corrosion performance. Three MMTs were elected for anti-settling agents , including MMT, organo-montmorillonites (OMMT1 and OMMT2) which are modified by HOOC(CH2)17NH3+, and CH3(CH2)17NH3+, respectively. The effects of type and amount of MMT on the mechanical property and appearance of MWPC were investigated by mechanical tests and scanning electron microscope. Polarization curve and electrochemical impedance spectroscopy in 3.5 % sodium chloride solution were used to evaluate the corrosion protection performances and coating porosity. Fourier transform infrared (FTIR) spectroscopy confirmed that the organic functional group was successfully reacted with emulsion, which increased the performance of MWPC. The results also showed that OMMT modified by HOOC(CH2)17NH3+ exhibited better effects than that modified by CH3(CH2)17NH3+.