SYNTHESIZATION & COATING OF HYDROXYAPATITE (HAP) ON TITANIUM AND ITS CHARACTERIZATION

Abstract

Orthopedic implants are mainly made of metals to endure mechanical stresses in service. Despite their good mechanical properties, metals and their alloys may be toxic for the human body New materials have been developed for orthopedic implants-and artificial teeth. Among these materials, HAp, which is known for its high biocompatibility and its unique property to integrate with bones which is called osteoconductivity, has attracted attention? Different techniques for HAp based biomaterials synthesis (mechanical methods, co-precipitation, bio-mimetic procedure, hydrothermal procedures) are described in literature. Hydrothermal synthesis offers many advantages over conventional ceramic synthesis methods. Hydrothermal synthesis is a technology for crystallizing materials (chemical compounds) directly from aqueous solution by adept control of thermodynamic variables (temperature, composition, environment). However there is always a concern about the corrosion and wear resistance of metallic bio-implants, in physiological fluids and their bioactivity. Thus it becomes mandatory to improve the surface properties of metallic biomaterial like Titanium in order to overcome the limitations although being still widely used in orthopedic implant applications. The processes of HVOF (High Velocity Oxy fuel) and Plasma Spray of Hydroxyapatite over titanium and its alloys is very well understood and being rigorously studied so far. Nevertheless the studies upon actual process and coatings produced, pertaining to biocompatibility, physical properties, dissolution behavior, effect of processing parameters, ablation plume characterization, mechanical properties, etc, encourage extending and exploiting this potential towards Pulsed Laser. deposition (PLD). This study incorporates the research pertaining to the synthesis of Hydroxyapatite with high temperature hydrothermal process and its coating on Titanium material to suit the application demands of orthopedic implant material. The base material is used in solution annealed form. After careful process parameters optimization of polishing and pulsed laser deposition (PLD) technique, the polished surface is coated with Hydroxyapatite film to approximately one . micron thickness with PLD. This surface is characterized physically, chemically mechanically, and for its osteoconductivity and bio-compatibility. Characterization techniques