Abstract:
Hydroxyapatite (HA) is a basic calcium phosphate (Ca10(PO4)6 (OH)2) mineral. Commercially available (HA) is similar in structure to the mineral phase of bone and therefore holds greatpromise as a biomaterial because it has the ability of bonding to bone.Hydroxyapatite is biocompatible and bioactive,its coating on metallic implants facilitates biological fixation between the prosthesis and the hard tissues, and increase the long-term stability and integrity of the implants. It produces an intermediate region between bone and implant, and enhances the transition of stress between them. Hydroxyapatite coatings have been fabricated by a variety of methods, including plasma spraying, sol–gel, chemical vapor deposition, ionbeam deposition, and electrochemical deposition.Compared to other coating techniques, dip coating technique has some evident advantages such as, high efficiency, easy control, simple set-up and relatively low expense.In this study Hydroxyapatite is deposited on type 316L stainless steel by dip coating. The films deposited at a fixed speed of 50 mm per minute gave good morphology of coating observed in SEM images.The optimization of solution for dip coating and then drying below 100°C produced crack free coatings. As HA coatings are severly affected by the sintering atmosphere and temperature, the sintering of HA coatings in controlled atmosphere at 700°C,900°Cand 1100°C for 1 hour was performed. The sintering at various temperatures below 1250°C did not alter the phase purity, however at 900°C the porosity was good enough for apatite formation in simulated body fluid (SBF). The hydroxyapatite coatings were characterized by several techniques including; x-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy dispersive X-ray(EDX).For this approach it is desirable to form denser HA coatings with a negligible quantity of impurities under suitable deposition conditions for medical applicatioN
