Biocompatibility, Bioactivity and Corrosion Resistance of Stainless Steel 316L Nanocoated with TiO2 and Al2O3 by Atomic Layer Deposition Method

Abstract

Atomic Layer Deposition (ALD) method has been used to synthesis nanocoatings thin films of Alumina, Titania, and Alumina/Titania multilayer on stainless steel AISI 316L at 250 °C deposition temperatures for the medical applications. SEM and EDX have been used to characterize the morphology of the films and the element analysis of the alloys and the thin films respectively. Open circuit potential, potentiostatic polarization (Tafel extrapolation) and cyclic polarization methods have been used to study the corrosion resistance of the films in Simulation Body Fluid (SBF) at 37 ± 1 °C. Immersion test in SBF for 2weeks at 37± 1 °C has been used to determine the biocompatibility of the films. Numbers of colonies and diffusion zone methods have been used after cultured non-pathogeni E-coli bacteria to demonstrate the bioactivity (toxicity effects) of the thin films. The SEM morphology observations show different particles shape and size of the Alumina (nanotubes shape around 10-20 nm in size) and Titania films (cauliflower particles shape around 20-50nm in size). The results also show that the corrosion resistance can be effectively enhanced by thin films, multilayer proved to be more corrosion protection than single layers, and Alumina has better corrosion resistance than Titania.