Preparation Of Porous Tantalum And Its Processes And Performance

Tantalum, excellent biocompatibility and biological activity, is widely attention and many studies recently. Nevertheless, compact tantalum has several inherent limitations such as, high density, relatively high modulus of elasticity, which cannot be implanted into body directly. Therefore, it will be research hotspot to design and manufacture porous tantalum that has excellent biocompatibility and biological activity, also has good mechanical properties and an appearance similar to cancellous bone.In this paper, the core objective of study was preparation porous tantalum by organic foam impregnation. First of all, according different concentrations of PVA and the organic foam with different pore size as templates can be obtained porous tantalum green body with different impregnate quantity,thus preparation the optimum porosity of porous tantalum. Secondly, porous tantalum green body is sintered by using high temperature and high vacuum. Through adjusting sintering temperatures and vacuum to optimize the mechanical properties of porous tantalum, reduce the carbon, oxygen impurity content in porous tantalum. Finally, the porosity porous tantalum is measured by hydrostatics, the compressive strength, bending strength and modulus of elasticity for porous tantalum are tested via electronic universal testing machine,SEM and vertical microscope were carried out to characterize its porosity, microstructure and section, The carbon, oxygen impurity content in porous tantalum is measured by CS-444 analysis instrument and TC-436 analysis instrument.Result shows that:PVA concentration effect on porosity of porous tantalum, with its concentration increased, the impregnate quantity increased and then reduced, while the porosity of porous tantalum reduced and then increased. When PVA concentration is 6%, the impregnate quantity is 448g, which can obtain the best porosity. There are three-dimensional, connected pore structures of porous tantalum prepared by organic foam impregnation, which is similar to foam scaffold. With the porosity increased, the compressive strength, bending strength and modulus of elasticity for porous tantalum are all reduced; the resistance capacity to deformation is variation. When the porosity is 60%, compressive strength of porous tantalum is 77.5MPa, bending strength is 94.12MPa and the elastic modulus is 2.8GPa, which coincide with bone trabecula in mechanical properties. With sintering temperature raised and particle size decreased, the diameter of sintering neck is increased, mechanical properties are raised, the fracture of tantalum is cleavage fracture, section present river pattern and absorbed energy of plastic deformation is very low. With sintering temperature raised and vacuum increased, carbon, oxygen content present decreased. Carbon, oxygen impurity elements formed interstitial solid solution in tantalum, which leads to mechanical properties of porous tantalum variation.