title: A Facile Method to Modify the Characteristics and Corrosion Behavior of 304 Stainless Steel by Surface Nanostructuring toward Biomedical Applications.
abstract: The study addresses how surface nanostructuring of AISI 304 stainless steel (SS) by surface mechanical attrition treatment (SMAT) influences its characteristic properties and corrosion behavior in Ringer's solution. SMAT of 304 SS induced plastic deformation, enabled surface nanocrystallization, refined the grain size, transformed the austenite phase to strain induced α'-martensite phase, increased the surface roughness, induced defects/dislocations, imparted compressive residual stresses at the surface, decreased the contact angle, and increased surface energy. The change in properties of 304 SS following treatment using 5 and 8 mm ⌀ balls for 15, 30, 45, and 60 min has caused a deleterious influence on its corrosion resistance in Ringer's solution, while an improvement in corrosion behavior is observed for those treated using 2 mm ⌀ balls. The increase in surface roughness, transformation of the austenite to α'-martensite phase, a higher extent of deformation, and the presence of larger number of defects/dislocations are main factors responsible for the lower corrosion resistance observed for 304 SS treated using 5 and 8 mm ⌀ balls in Ringer's solution. In spite of having these attributes with a relatively lower extent, 304 SS treated using 2 mm ⌀ balls offered a better corrosion resistance and exhibits a better passivity. For those treated using 2 mm ⌀ balls, the ability of the nanocrystalline surface to promote passivation outweighs the deleterious influences caused by the limited amount of deformation and defects/dislocations. Based on the findings of this study, it is recommend that SMAT of 304 SS using 2 mm ⌀ balls for 15-30 min is the optimum condition to achieve the suitable surface profile, surface characteristics with better corrosion resistance.
authors.affiliation: †CSIR-National Metallurgical Laboratory, Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113, India.|‡Department of Analytical Chemistry, University of Madras, Maraimalai (Guindy) Campus, Chennai 600 025, India.|∥Research Center for Strategic Materials, Materials Recycling Design Group National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Balusamy
authors.initials: B
authors.lastname: Thangaraj
authors.affiliation: †CSIR-National Metallurgical Laboratory, Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113, India.|§Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Sankara Narayanan T S
authors.initials: SN
authors.lastname: Nellaiappan
authors.affiliation: ‡Department of Analytical Chemistry, University of Madras, Maraimalai (Guindy) Campus, Chennai 600 025, India.
authors.forename: Ravichandran
authors.initials: R
authors.lastname: Kulandaivelu
authors.affiliation: §Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Lee
authors.affiliation: ∥Research Center for Strategic Materials, Materials Recycling Design Group National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Nishimura
keywords: compressive residual stress; contact angle; corrosion behavior; dislocations; phase transformation; plastic deformation; surface nanocrystallization; surface topography