Application of potential pulse method to the corrosion behavior of the fresh surface formed by scratching and sliding in corrosive wear

Corrosive wear in an electrolyte solution is controlled by both mechanical and electrochemical factors. The authors have found in previous papers that the latter was very significant for type 304 stainless steel under recipro cating sliding. Especially, the corrosion rate at the fresh surface formed by mechanical action, i.e., sliding, is higher than at normal surfaces, and the corrosion behavior can be estimated by the current density obtained fr om the potential pulse method (PPM). In this paper the authors verify the a dequacy of the estimation method above for scratching and unidirectional sl iding conditions. Specimens used were pure iron and type 304 steel, and a s cratch indenter was an Al2O3 tip, which was dropped on the rotating specime n surface in 0.1 M Na2SO4 solution at different potentials. The result show ed that the electric charge density passed through the specimen under the s cratch and unidirectional sliding almost coincided with the estimated value from the PPM. Therefore, it was concluded that the current density from th e PPM can be applied to the estimation of the corrosion rate at the fresh s urface in corrosive wear. (C) 1999 Elsevier Science S.A. All rights reserve d.