Iodine in the form of a charge transfer complex in organic solvents is useful as a lubricant and cutting fluid. Unfortunately, such fluids and their vapors are very corrosive to steels. Experiments performed with the object of understanding such corrosion have shown that water is essential; in the absence of water neither the vapor nor the fluid corrodes steel. Corrosion is not appreciably affected by the presence or absence of oxygen. This observation is in conflict with the theory proposed by Gindin and Pavlova,1 according to which oxygen reacts with ferrous iodide to accelerate the reaction. We believe that corrosion of steel by iodine plus water comprises the following steps:
The corrosion rate accelerates as the concentration of iodide ions, and hence of I3− complex, increases.
A simple experiment confirmed this mechanism. Steel specimens of about 40 cm2 area were immersed in 250 cc of water...
