Real time spectroelectrochemical growth and corrosion resistance monitoring of lead carboxylate coatings in an environmental cell (eCell)

Heritage lead is subject to attack from organic acids emitted from wood and other sources in its environment. Coating the lead is a possible solution if the source cannot be eliminated. We present a study of the growth and corrosion resistance of a lead carboxylate coating, (CH3(CH2)8COO)2Pb, deposited using an environmentally friendly process. Using a combination of synchrotron X-ray diffraction and electrochemical impedance spectroscopy we demonstrate the monitoring of the growth of the coating in real-time in an environmental cell configured for electrochemistry. Then, using the same cell, we show the dynamics of exposing the coating to 6.3% (by mass) acetic acid vapour in air at 75% relative humidity. Whereas unprotected lead shows significant corrosion in under 2 h, a ~1.5 μm coating can withstand the acid vapour for up to 7 h. However, some coatings fail much sooner but nevertheless still show some residual inhibition. Data are correlated with ex-situ techniques including mass gain measurements