Abstract A polarization curve around the corrosion potential has been obtained for zinc immersed in a near neutral solution by using a potentiostat controlled by a microcomputer. The polarization data was fitted by the microcomputer to the general electrochemical equation for a metal corroding in solution and this resulted in values for the corrosion rate and the Tafel parameters. The corrosion of zinc in a de-aerated sodium chloride solution at pH 5.3 was used to demonstrate the method. After 1 h immersion, the anodic and cathodic Tafel slopes approached constant values of 60 and 120 mV respectively. Rotating disc studies did not reveal any contribution from a diffusion controlled cathodic process.