Tin corrosion in highly acidic solutions containing ethylene glycol oligomers and halides: An electrochemical quartz crystal microbalance study

Tin corrosion in 1 M H₂SO₄ solutions containing 0.01 M Sn(II), 0.01 M ethylene glycol or its oligomers, and 30 μM of various halides is studied by the electrochemical quartz crystal microbalance method. The current density of the tin electrode corrosion is found to approach a few tens of μA cm^?2. In the presence of Sn(II), the current density is nearly half that in its absence. The corrosion potential steadily increases with time, approaching a certain limit. In solutions containing Sn(II), the limit practically corresponds to the equilibrium potential of the Sn/Sn²⁺ electrode. The corrosion rate barely depends on the oligomer nature even up to tetraethylene glycol. Halides accelerate the corrosion process. Their action intensifies at initial time instants (up to 15–20 min) in the series Cl^? < Br^? < I^?. The corrosion impedance equals ～1000 ohm cm². It may be ignored when analyzing the overall impedance of the tin electrode in the frequency region extending from 0.1 Hz to 50 kHz.