Hydroxyapatite is chemically similar to the mineral components of bones. It is one of the few materials that are considered bioactive, meaning that it will support bone in growth and osseointegration when used in orthopedic and dental applications. It is expected that the incorporation of a ceramic reinforcement having grain size less than 100 nm would improve mechanical properties. In this work, hydroxyapatite–forsterite composite coatings were prepared using sol-gel method by dipping stainless steel (316L) substrates in a sol containing hydroxyapatite as matrix and forsterite (10, 20, 30 wt%) as reinforcement. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to investigate structure and morphology of the coating before and after immersion in simulated body fluid at 37?C. The obtained results showed that apatite layer can be formed on the surface of the coating soaked in simulated body fluid for 1, 2, 3 and 4 weeks, which indicate that this coating possesses good bioactivity. To observe the corrosion behavior, potentiodynamic polarization test was informed in ringer solution. The reduced corrosion current observed for all of the coated samples, confirmed the significant improvement corrosion resistance of the substrates with composite hydroxyapatite-forsterite coating. Results suggested that this composite hydroxyapatite-forsterite coating might be potentially useful for biomedical applications, especially as a coated implant for hard tissue treatment. Key words: nanocomposite, coating, hydroxyapatite, forsterite, bioactivity, corrosion
