Surface Characteristics and In Vitro Corrosion Behavior of HAp-coated 316L Stainless Steel for Biomedical Applications

Abstract

In this chapter, electric discharge coating (EDC) was employed for the surface modification of medical grade 316L stainless steel with hydroxyapatite nanopowder using copper as a tool electrode with reverse polarity. Experimentation was performed according to Taguchi’s L18 orthogonal array to assay the influence of input machining parameter on surface characteristics of modified surface. In vitro electrochemical corrosion analysis was executed to authenticate the enhanced corrosion resistance of the specimen. The homogenous porous surface and deposition of powder particles were examined using scanning microscopy in conjunction with the formation of bioactive and intermetallic compounds, carbides and silicides on the machined surface inspected using X-ray diffraction technique, promoting the biological compatibility with human body. Furthermore, modified surface showed better corrosion resistance with a corrosion rate of 0.0972 mm/year compared to substrate exhibited a higher corrosion rate of 1.79 mm/year. The observations validate the improved corrosion protection and bioactivity of 316L stainless steel for biomedical applications.