Adsorption studies of water on copper, nickel, and iron: Assessment of the polarization model

In the atmospheric corrosion of copper, nickel, and iron, the adsorption of water affects the corrosion rates. Knowledge of water adsorption and metal oxyhydroxide formation is important in understanding the atmospheric corrosion process. The purposes of the present research were (i) to measure the adsorption of water on metal surfaces as a function of temperature and relative humidity (RH) and (ii) to assess Bradley's polarization model of adsorption. In the present research, the quartz-crystal microbalance (QCM) technique was used to measure the mass changes of copper, nickel, and iron at 0 to 100% relative humidity and 7 to 90°C under nitrogen and air environments. Less water was adsorbed on copper, nickel, and iron which form oxides than on gold. The amount of water adsorption was similar on copper, nickel, and iron under N₂ and air carrier gases. Functional relationship was first proposed as a way to include dipole/induced dipole interactions between the adsorbents and water layers.