The protective action of two vapour phase inhibitors on the corrosion of mild steel

The action of two vapour phase inhibitors (VPI), dicyclohexyl‐ammonium nitrite (DICHAN) and dicyclohexylamine (DICHAMIN), on the atmospheric corrosion of mild steel at a relative humidity of 100% and under isothermal conditions (25 °C) has been studied. In order to obtain electrochemical data with thin adsorbed moisture layers a vapour phase inhibitor monitor (VPIM) was developed. A check of the data was done by three electrochemical techniques and by the image analysis technique. The tests carried out have revealed that the corrosion rate of mild steel decreases in the presence of DICHAN and DICHAMIN. With the VPIM and the electrochemical techniques used it is possible to understand the inhibition mechanism of these two vapour inhibitors on the atmospheric corrosion of steel.