CORROSIVE WEAR BEHAVIOR OF 304-L STAINLESS-STEEL IN 1-N H2SO4 SOLUTION .2. EFFECT OF CHLORIDE-ION CONCENTRATION

Abstract

Results on the influence of chloride ion levels on the corrosive wear rate of 304-L stainless steel in 1 N H2SO4 are discussed. The corrosive wear rate was measured at two different applied potentials: 200 and 600 mV (vs. a saturated calomel electrode (SCE)). At an applied potential of 200 mV(SCE) the corrosive wear rates increased linearly with increasing chloride ion concentration from 0 to 23.4 g l-1. At 600 mV(SCE) the corrosive wear rates showed an increase similar to those at 200 mV(SCE) below the critical chloride ion concentration necessary for the occurrence of pitting. In addition, potentiokinetic, inductively coupled plasma spectroscopy, a.c. impedance, current decay transient, and scanning electron microscopy measurements were carried out. It is suggested that the increase in corrosive wear rate in the presence of chloride ions is caused by the decrease in current efficiency for the formation of a passivating oxide film caused by the presence of chloride ions.