Electrochemical corrosion behaviour of heat-treated AISI 304 austenitic stainless steel in inorganic acid mixture

Abstract

Attempts to study the effect of heat-treated AISI 304 stainless steel ina nitrated-sulphuric acid environment. Potentiodynamic polarization studies of heat-treated AISI 304 SS samples were carried out in 75 percent H2SO4 - 25 per cent HNO3 acid environment using a PARC-273 potentiostat/galvanostat. For comparison, potentiodynamic polarization studies of untreated AlSI 304 SS were also carried out under similar conditions. Potential Versus current density were plotted and the values of Ip and Ic were calculated. The curve depicts that the value of I-corr increases with increasing heat treatment temperature and time of exposure. abrupt changes in Icorr were observed in the sample heat-treated at 500 degrees C and 600 degrees C for 120 minutes and 60 minutes respectively. Infers that heat treatment temperature and time of exposure to heat accelerated the corrosion in the acid. Attributes this to precipitation of chromium carbide at the grain boundaries.