چكيده لاتين :
In this research pitting Corrosion of a sensitized 3J6 stainless steel was investigated
employing potentiodynamic, potentiostatic techniques . Sensitization process was carried out on
as-received alloy by submitting the specimen in electric furnace set at 650°C for fiv e hours and
then the specimen was quenched 25°C water. Potentiodynamic polarization of as received and
sensitized specim ens in 1M H2S04 solution at room temperature and 70°C clearly revealed that
the sensitization process has caused a magnificent change on electrochemical behavior of the
specimen by changing critical current density for passivation, passivation potential and passive
current density. Optical microscopy examination of the specimen surface after oxalic acid
electrochemical etching also showed the deterioration of grain boundary of sensitized specimen
due to chromium carbide precipitation in compared to as-received one. Several anodic
potentiodynamic polarization on rode shaped working electrodes prepared from as-received and
sensitized specim en in 3.5% NaCl test solution proved an average ~220 mV drop in pitting
potential due to sensitization. Anodic pot entiostatic polarization at 400 and 200 mV above
corrosion pot ential also demonstrate the deterioration ofpitting resistance ofalloy as a result of
sensitization. Scanning electron microscopy examination of anodically polarized of sensitized
specimen at 700 mVprior and after oxalic acid etching revealed large stable pits with lacy cover
and also open pits with deep crevice for etched specimens
