The influence of the potential sweep rate on the shape of polarization curves

Abstract The influence of the potential sweep rate on the shape of polarization curves and the computation of R pa has been examined by accounting for the adsorption-desorption phenomena at the electrode surface and simulating the behaviour of the metal-solution interface with a suitable linear network. Mathematical developments for determining the network response when a triangular wave is applied to its terminals are based on the use of the mesh method and Laplace transform. Short considerations concerning the network proposed by Macdonald are also given. Calculations with reference to a two-mesh network were performed using specific Quickbasic programs and single precision. Examination of the trend of several i (Δ E ) functions over the [−10,10] mV Δ E interval showed that their distortion was usually negligible for a 0 ⩽10 mVs −1 and C ⩽10 −3 F cm −2 . Significant distortion was only observed for a 0 ⩾100 mVs −1 . The influence of adsorption-desorption phenomena affects the shape of i (Δ E ) inside the cathodic zone over an interval having Δ E i as left bound, the position of its right bound depending on a 0 . For all the cases examined and a 0 −1 the values of the three determinations of R pa are practically coincident with the values of R p when C ⩽10 −3 Fcm −2 , a difference being observed when a 0 >10 mVs −1 and C sime;10 −3 Fcm −2 . At last, examination of the response of the network proposed by Macdonald provided a further confirmation of the previous results.