Study on Corrosion Resistance of 430 Stainless Steel Containing Copper under Simulated Normal Saline Environment

Abstract

In order to study the corrosion behavior of copper-containing 430 stainless steel in normal saline environment, the corrosion resistance of ferritic stainless steel containing Cu 430 in simulated physiological saline solution (0.9% NaCl, mass fraction, the same below) was studied using electrochemical testing methods. The semiconductor properties and surface composition of the passivation film were characterized using Mott-Schottky curves and X-ray photoelectron spectroscopy (XPS), and the surface morphology after electrochemical corrosion was observed using scanning electron microscopy (SEM). Results showed that in 0.9% NaCl solution, passive films were formed on the surface of 430 ferritic stainless steel without Cu and with 1.57% Cu. Compared with stainless steel without Cu, the corrosion resistance of 1.57% Cu stainless steel was reduced. Because Cu element inhibited the formation of Cr2O3 in the passivation film of 430 ferritic stainless steel, the defect density in the passivation film increased. Additionally, the pitting corrosion pits of 430 ferritic stainless steel were mainly distributed near the copper-rich phase after adding the copper element, and the copper-rich phase destroyed the continuity of the passive film, resulting in the decrease of corrosion resistance and the increase of surface morphology damage of stainless steel.

Keywords

• 430 ferritic stainless steel|1.57% cu|electrochemistry|passivation membrane|corrosion resistance