The Preparation By Powder Metallurgy Route For Porous Biomedical Titanium And Its Properties

Titanium (Ti) and titanium alloys have widely used as metallic biomaterials owing to their good biocompatibility, mechanical properties, low density and corrosion resistance. Use of porous implants allows mechanical interlocking of bone with the implant by substantial bone ingrowths. Additionally, by adjusting the porosity of the implant material, stiffness and strength can be controlled in order to reduce the stress-shielding effect. Therefore, So, Porous titanium as biomaterials will be suitably used in clinical application.In this paper, porous titanium was successfully prepared by powder metallurgy route with pure magnesium as pore-forming agent. Surface morphological characteristics of the pores were characterized using image processing techniques. Pore structure of porous titanium was investigated by optical microscopy and SEM images. Mechanical properties (Young’s modulus and compressive strength) of the specimens were measured by universal mechanical testing. Crystallization structure of the porous titanium treated by mineralization and micro-arc oxidation was studied by XRD. The influence of preparation parameters such as pre-forming pressure, amount and size of pore-forming agent, sintering temperature on the porosity and mechanical properties of the porous titanium were investigated in detail. Surface chemical treatment processing and surface modification by micro-arc oxidation processing were performed in order to improve the biocompatibility of porous titanium.The porous titanium with pore size of10-50μm and100-500μm were prepared successfully. The results show that the porosity of porous titanium was significantly affected by pre-forming pressure and the amount of pore-forming agent, while the size of Mg powder and sintering temperature have little influence on the porosity. The porosity of porous titanium increased with increasing of amount of pore-forming agent, while, Young’s modulus and compressive strength of porous titanium decreased with increasing of amount of pore-forming agent. Typical mechanical properties such as Young’s modulus and compressive strength of porous titanium are around10-15GPa and344-489MPa, respectively, which is closely similar to the mechanical properties of dental substantial bone. This means that the experimental porous titanium is suitable for the implants of dental substantial bone.Furthermore, Ca/P compounds would deposit on the surface of porous titanium after biomineralization in simulated body fluid (SBF), which can induce bone-cell growth, further improving bioactivities. After surface modification by micro-arc oxidation processing, the thin layer of Rutile-TiO2and Anatase-TiO2phase with massive micro-pores was formed on the surface of porous titanium, which suggested that the massive micro-pores would further increases the binding force between the implant and natural bone and benefit for the transport of body fluids and nutrients.