Effect of phosphine on acid corrosion of iron

The effect of the phosphine‐concentration (10 −8 –10 −3 M) in strong acid solutions (pH = 0) on the corrosion rate of pure iron and Fe‐ 0.12% P alloy has been investigated. It was shown that at low concentrations (10 −7 –10 −6 M), phosphine accelerates the corrosion of iron, whereas at adequately high concentrations (10 −5 –10 −3 M) it has inhibitory properties. In the presence of PH 3 the cathodic reduction of hydrogen ions is strongly accelerated. At the same time, the increase in PH 3 concentration causes an increase of surface coverage by PH 3 molecules, which results in the inhibition of both partial electrode processes.