Anodic Kinetics of NiCr[Mo] Alloys During Localized Corrosion: I. Diffusion-Controlled Dissolution

作者：Carcea Anatolie G^*; Yip Eric Y W; He David D; Newman Roger C

来源：Journal of the Electrochemical Society, 2011, 158(6): C215-C220.

DOI：10.1149/1.3579507

Artificial pit electrodes have been used to measure the pitting dissolution kinetics in the anodic limiting current region for a range of Ni-22Cr-xMo (wt %) alloys with x 0, 3, 6, 9 and 13. Most of the data were obtained at 25-90 degrees C using 1 M NaCl solution. Type 316 stainless steel and pure nickel were used for comparison. At high temperatures the anodic limiting current density for the NiCr(Mo) alloys (x 0, 3, 6, 9) is nearly the same as that of stainless steel, other things being equal; at intermediate temperatures the NiCr(Mo) alloys give higher i(lim) values. Changing the NaCl concentration between 0.1 and 1 M causes a 20% change in i(lim) at a given pit depth, and the reasons for this are discussed. Comparison of pure Ni and Ni-22Cr shows a 35-40% higher i(lim) for the latter at a given pit depth, and the reasons for this are discussed. Literature values of solubility and diffusivity, and a 1-D finite difference model, are used to rationalize - in part - the limiting current densities and associated average diffusivities in terms of concentration-dependent diffusivities.

• 出版日期2011