Title of article :
DETERIORATION OF PITTING CORROSION OF 316 STAINLESS STEEL BY SENSITIZATION HEAT TREATMENT
Author/Authors :
Moayed، M. H. نويسنده Materials and Metallurgical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Iran. ,
Issue Information :
فصلنامه با شماره پیاپی 7 سال 2005
Abstract :
In this research pitting Corrosion of a sensitized 316 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 five hours and
then the specimen was quenched 25°C water. Potentiodynamic polarization of as received and
sensitized specimens in 1M H2SO4 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 specimen in 3.5% NaCl test solution proved an average ~220 mV drop in pitting
potential due to sensitization. Anodic potentiostatic polarization at 400 and 200 mV above
corrosion potential also demonstrate the deterioration of pitting resistance of alloy as a result of
sensitization. Scanning electron microscopy examination of anodically polarized of sensitized
specimen at 700 mV prior and after oxalic acid etching revealed large stable pits with lacy cover
and also open pits with deep crevice for etched specimens
Journal title :
Iranian Journal of Materials Science and Engineering
Journal title :
Iranian Journal of Materials Science and Engineering