Preparation And Mechanical Properties Of Porous Titanium

Titanium is a main metal material applied to the clinic due to its good biocompatibility, mechanical property and corrosion resistance. Porous structure of the porous Ti reduces the mechanical properties, then may minimize or eliminate the stress-shielding problem. The porous structure allows improved mechanical interlocking between the implant biomaterial and the surrounding natural bone. In recent years, researches on porous Ti have gained much attention.To meet the requirements of the implant biomaterial, porous Ti was produced by Granulating-Loose Pack Sintering Method, this method have advantage of simple and low cost, porous Ti made by this method have not only interconnected pore structure, but also included macropores size and micopores size pore structure. According to the characteristics of Ti powder, the methods and parameters of Granulating-Loose Pack Sintering Method(such as the choice of binders, amount of binders, weight of solid and liquid and sintering temperature, etc) were studied, and we also prepared porous Ti with three-dimensional interconnected pore structure by this method. Their physical properties, pore characteristics and mechanical properties were characterized, The pore characteristics and mechanical properties under different sintering temperature were studied and the pore size distribution and content of O, C and N were also investigated.Firstly, the impact of the choice of binders, amount of binders, weight of solid and liquid on granulation were studied in this paper. The results showed when we choice PVA ([-CH2CHOH-]n) as binders(2%wt.%PVA+water, weight of solid and liquid is10:1) can make well-distributed Ti particles, the Ti particles have moderate strength and also meet the need for sintering.Subsequently, the impact of sintering temperature and different Ti particles on surface morphology, porosity and mechanical properties were studied in this paper. The results showed that sintering temperature has a major impact on the surface morphology and physical properties of porous Ti. Upon loose powder sintering, porosity under different mesh were observed to decrease linearly with increasing temperature at almost the same rate; when sintering temperature increased and the holes became round from irregular shape gradually, mechanical properties of porous Ti increased at the same time. The study also found that when the Ti particles became bigger, mechanical properties of porous Ti increased. When sintering temperature was1150℃, porous Ti included macropores size100-400μm and micropores size10μm around. The porosity of porous Ti was66%,64%,62%under different Ti particles, the compressive strength of porous Ti was18MPa,39MPa,43MPa, respectively, which meet the requirements of cancellous bone. In addition, the content of C, O and N in porous Ti which made by Granulating-Loose Pack Sintering Method can meet the requirements of ISO5832-2(Ti Grade4)The research is funded by National"973" Project "the foundation research of sintering metal composites"(Project No.2010CB735807) and finished in State Key Laboratory of Porous Metal Materials which relies on Northwest Institute for nonferrous metal research.