Statistical atomic-topographic model of the active dissolution of metals with point lattice defects. The effect of point defects (vacancies and impurity atoms) on the metal dissolution rate

Abstract

A physicochemical model is put forward for the dissolution (corrosion) of a metal with point lattice defects, i.e., vacancies and impurity atoms with corrosion stability radically different from that of the base metal. The model takes into account the substantial difference in the dissolution rates of the base metal atoms from positions with different numbers of neighboring atoms, which leads to the formation of characteristic nanofragments of the atomic surface relief. These fragments determine the dissolution rate. The point defects substantially affect the dissolution rate of the base metal exclusively due to their active involvement in the formation of the atomic relief. The equations describing this model allow the polarization curves of active dissolution of the base metal to be calculated as a function of the defect concentration.