Enhanced passivation layer by Cr diffusion of 301 stainless steel facilitated by SMAT

Temitope Olugbade

Abstract

Enhanced passivation layer by Cr diffusion of 301 stainless steel facilitated by SMAT

AISI 301 stainless steel (SS) is known for its high strength
and hardness but tends to be less corrosion resistant for
many applications. Several attempts have been made in
the past to investigate its corrosion behaviour by different
methods. However, current knowledge is insufficient on
its corrosion resistance when subjected to surface treatment.
In this work, a new route to enhance the corrosion
resistance of nanostructured 301 SS using surface mechanical
attrition treatment (SMAT) method is described.
SMAT improves the mechanical properties of 301 SS by
the formation of a nanostructure layer on the material
surface. Compared to the as-received 316 and 304 SS
counterparts, the present nanostructured 301 SS exhibits
an improved corrosion behaviour by a lower corrosion
current density (1.308 mA/cm2), higher corrosion potential
(-0.071 V), higher phase angle and impedance, better
charge-transfer resistance, and Cr content. The improved
corrosion resistance can be attributed to the ability of
SMAT to facilitate the move of Cr on the surface, which
forms a stronger passivation layer with a new mechanism
of passivation that may save a lot of noble metals.