Papers by Keyword: Titanium (Ti)

Abstract: Titanium reinforced with hydroxyapatite (TiHA) prepared using 15% of titanium and 3 different sinterizing temperatures 1100, 1200 and 1300 oC showed a significant increase in cell proliferation, when compared to the control.

Abstract: In the framework of producing new composite biomaterials, this study investigated the interfacial interactions between molten brand new biocompatible glasses with model formulations and Ti, hydroxyapatite, zirconia and a CrNi-steel. Analysis, by grouping the results of each particular substrate, indicates that Ti reduces the molten glass-oxides, HA tends to diffuse with them, zirconia grain-boundaries are vulnerable towards them, and Cr-Ni-steel very poorly adhere to them. Analysis, by grouping the results of each particular glass, indicates that the matching of their expansion coefficient with that of substrate and crystallization affect the formation of continuous or cracked interface. Viscosity and surface tension of glasses determine wettability. Wettability is not however determinative index of evaluating the quality and the strength of the resulting interfaces.

Abstract: An in vivo biocompatibility test of a novel biocomposite, with major phases of CaTiO3 and Ti2O, and minor phases of AlTi3, TiO, CaO and Al2O3, was conducted on rats using subcutaneous implantation. The biocomposite and titanium alloy control specimens were removed at 6 and 14 weeks post-implantation. Histological examination revealed no significant adverse reaction of the surrounding tissue to the either the biocomposite or the control material. We conclude that the composite is well tolerated in a physiological environment.

Abstract: Concentrated H2SO4 acid was applied to pretreatment for the alkaline treatment of commercially pure titanium, and the effect of acid-etching on apatite-forming ability of alkaline-treated titanium in a simulated body fluid (SBF) was investigated. Characterization analysis revealed that the concentrated H2SO4 etching formed much amount of sodium titanate, resulting a large amount of formation of apatite in SBF. It is confirmed that the etching in concentrated H2SO4 enhance apatite-forming ability of alkaline-treated titanium.

Abstract: Wear behavior of titanium materials such as C.P.Ti, Ti-6Al-4V and Ti-6Al-7Nb, was studied in simulated body fluids by means of the pin-on-disk type wear testing. The mass loss in wear testing increased with increasing the sliding distance. The a+b type titanium alloys, Ti-6Al-4V and Ti-6Al-7Nb, exhibited higher wear resistance than the C.P.Ti. Average size of the wear debris was 4.5 µm and 3.7 µm for C.P.Ti and the a+b type titanium alloys, respectively. The elution of metallic constituents into 1 mass% lactic acid solution was detected after the wear test.

Abstract: First-principles pseudopotential calculations were performed to investigate atomic and electronic structures of titanium (Ti) dopants in alumina (Al2O3). It was found that a substitutional Ti3+ defect induced an extra level occupied by one electron within the band gap of Al2O3. When two or more substitutional Ti3+ defects were located closely to each other, the defect-induced levels exhibited strong bonding interactions, and their formation energies decreased with increasing numbers of Ti3+ defects. This indicates that association and clustering of substitutional Ti3+ defects in Al2O3 can take place due to the interaction of the defect-induced levels.

Abstract: The oxidation behavior of the equiatomic TiNi alloy was investigated at 600-900oC. The oxidation resistance of the TiNi alloy was better than the pure Ti alloy, but worse than the pure Ni alloy. The oxide scales consisted of TiO2, with and without embedded particles of TiNiO3 and Ni. The subscale matrix phase was (TiNi3+TiNi) at 600oC, TiNi3 at 700oC, (Ni+TiNi3) at 800oC, and Ni at 900oC. Oxidation was mainly governed by the inward diffusion of oxygen, and the outward diffusion of Ti and a bit of Ni. Detailed microstructures and the oxidation mechanism are proposed.

Abstract: In recent years, significant advances have been made in regard to the creep deformation behavior of two phase titanium alloys. It has been shown that the creep resistance depends on a number of factors, including the shape of the component phases, the strength difference between the phases, and the stability of the beta phase. For example, in two-phase materials with a similar volume fraction and morphology of phases, if the beta phase is less stable, then the creep resistance is lower. These developments will be reviewed and the reasons for such effects will be suggested.