In Vitro Corrosion Behaviour of Ti–6Al–4V and 316L Stainless Steel Alloys for Biomedical Implant Applications

Pulsed laser deposition technique is one of the methods to coat the hydroxyapatite on 316L stainless steel and Ti–6Al–4V implants, which is used in orthopaedics and dentistry applications. In this study, hydroxyapatite (HAP) ceramics in the form of calcium phosphate were deposited on Ti–6Al–4V and 316L stainless steel by the pulsed laser deposition method. The coated thin film was characterised by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (EDS) and atomic microscopy. The corrosion studies were carried out on coated and uncoated samples using potentiodynamic polarisation studies in simulated body fluid (Hanks’ solution). The bioactivity of the Hap-coated samples on Ti–6Al–4V and 316L stainless steel was evaluated by immersing them in simulated body fluid for 9 days. XRD and EDS analyses confirmed the presence of HAP. The corrosion studies showed that the treated samples have better corrosion resistance compared to Ti–6Al–4V and 316L stainless-steel substrates. The formation of apatite on treated samples revealed the bioactivity of the HAP-coated substrates. HAP-coated Ti–6Al–4V provides higher corrosion protection than the HAP-coated 316L stainless-steel substrates