Laser surface modification of 316L stainless steel

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Vol. 106; no. 2; pp. 569 - 577
• Main Authors: Balla, Vamsi Krishna, Dey, Sangeetha, Muthuchamy, Adiyen A, Janaki Ram, G D, Das, Mitun, Bandyopadhyay, Amit
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.02.2018
• Subjects: Argon - chemistry; Austenitic stainless steels; Biocompatibility; Biomedical materials; Boundaries; Cell Line; Cell proliferation; Cell Proliferation - drug effects; Cell Survival - drug effects; Continuous radiation; Corrosion; Corrosion prevention; Corrosion resistance; Corrosion resistant steels; Crystal structure; Crystallography; Electron backscatter diffraction; Fetuses; Grain boundaries; Humans; Isotonic Solutions - chemistry; Isotonic Solutions - pharmacology; Lasers; Materials research; Materials science; Materials Testing; Neodymium lasers; Osteoblasts - cytology; Osteoblasts - drug effects; Planes; Semiconductor lasers; Stainless steel; Stainless Steel - chemistry; Stainless Steel - pharmacology; Surface energy; Surface properties; Surface roughness; Therapeutic applications; Viability; Water - chemistry; Wettability; YAG lasers; 316L SS; bone implants; Laser surface melting; Ni release and in vitro biocompatibility
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.33872

Medical grade 316L stainless steel was laser surface melted (LSM) using continuous wave Nd-YAG laser in argon atmosphere at 1 and 5 mm/s. The treated surfaces were characterized using electron backscatter diffraction to study the influence of top surface crystallographic orientation and type of grain boundaries on corrosion resistance, wettability, and biocompatibility. The laser scan velocity was found to have a marginal influence on the surface roughness and the type of grain boundaries. However, the crystal orientation density was found to be relatively high in 1 mm/s samples. The LSM samples showed a higher concentration of {101} and {123} planes parallel to the sample surface as well as a higher fraction of low-angle grain boundaries. The LSM samples were found to exhibit better surface wettability and enhanced the viability and proliferation of human fetal osteoblast cells in vitro when compared to the untreated samples. Further, the corrosion protection efficiency of 316L stainless steel was improved up to 70% by LSM in as-processed condition. The increased concentration of {101} and {123} planes on surfaces of LSM samples increases their surface energy, which is believed to be responsible for the improved in vitro cell proliferation. Further, the increased lattice spacing of these planes and high concentration of low-energy grain boundaries in LSM samples would have contributed to the better in vitro corrosion resistance than untreated 316L stainless steel. Our results indicate that LSM can be a potential treatment option for 316L stainless steel-based biomedical devices to improve biocompatibility and corrosion resistance. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 569-577, 2018.