http://sistemas.eel.usp.br/docentes/arquivos/2166002/1234Nb/Geetha-review2009.pdf

Ti based biomaterials, the ultimate choice for orthopaedic implants – A review

Ti-based alloys are finding ever-increasing applications in biomaterials due to their excellent mechanical, physical and biological performance. Nowdays, low modulus β-type Ti-based alloys are still being developed. Meanwhile, porous Ti-based alloys are being developed as an alternative orthopedic implant material, as they can provide good biological fixation through bone tissue ingrowth into the porous network. This paper focuses on recent developments of biomedical Ti-based alloys. It can be divided into four main sections. The first section focuses on the fundamental requirements titanium biomaterial should fulfill and its market and application prospects. This section is followed by discussing basic phases, alloying elements and mechanical properties of low modulus β-type Ti-based alloys. Thermal treatment, grain size, texture and properties in Ti-based alloys and their limitations are dicussed in the third section. Finally, the fourth section reviews the influence of microstructural configurations on mechanical properties of porous Ti-based alloys and all known methods for fabricating porous Ti-based alloys. This section also reviews prospects and challenges of porous Ti-based alloys, emphasizing their current status, future opportunities and obstacles for expanded applications. Overall, efforts have been made to reveal the latest scenario of bulk and porous Ti-based materials for biomedical applications.

/pdf/new-developments-of-ti-based-alloys-for-biomedical-1vs3nsqg8x.pdf

New Developments of Ti-Based Alloys for Biomedical Applications

The urge to replace missing teeth dates back to the origin of medicine. Along history, organic materials, metals, alloys, polymers, glasses, and carbon were used to substitute teeth, but only in the past thirty years was a truly scientific approach implemented introducing the concept of osseointegration. This review aims at recapitulating the materials of choice, the surface modifications, and the most updated research advancements in the field of oral osseointegrated implants. As the accepted clinical standard, commercially pure Titanium, Ti–6Al–4V and, to a lesser extent, zirconium dioxide will be described from the perspective of physical, mechanical, and biological features, together with in vitro, in vivo, and clinical assessment of biocompatibility. Outlines of the researches that are presently conducted in an endeavor to limit the drawbacks of the current technology are also provided. Novel Titanium alloys such as Ti–Zr and Ti–20Nb–10Zr–5Ta, Zr61Ti2Cu25Al12, innovative production methods for non metallic materials as well as ceramic composites will be considered as possible promising candidates for future dental implants

Biomaterials for dental implants: current and future trends

NiCoCrAlTaY bond coat was deposited by cold spraying to assemble thermal barrier coatings (TBCs). The microstructure of the cold-sprayed bond coat was examined using scanning electron microscopy. TBCs consisting of cold-sprayed bond coat and plasma-sprayed YSZ were pretreated at different conditions to form different thermally grown oxides (TGOs) before thermal cycling test. The influence of the TGO composition on the thermal cyclic lifetime was quantitatively examined through the measurement of the coverage ratio of the mixed oxides on the bond coat surface. The results showed that the bond coat exhibited a dense oxidation-free microstructure, and TGOs in different morphologies and constituents were present after thermal cyclic test. The formation of TGOs was significantly influenced by pretreatment conditions. Two kinds of TGO were detected on the surface of bond coat after the spallation of YSZ coatings. One is the α-Al2O3-based TGO and the other is the mixed oxide. It was found that the thermal cyclic lifetime is inversely proportional to the coverage ratio of the mixed oxides formed at the bond coat/YSZ interface. The high coverage ratio of the mixed oxide on the interface leads to the early spalling of YSZ coating.

Influence of TGO Composition on the Thermal Shock Lifetime of Thermal Barrier Coatings with Cold-sprayed MCrAlY Bond Coat

Structural and magnetic properties of magnetocaloric LaFe13–xSix compounds synthesized by high energy ball-milling

Thermodynamic modeling of oxidation of Al–Cr–Ni alloys

Lanthanum–silicon system

Cerium–silicon system

By using differential thermal analysis, metallography and X-ray examination the experimental phase diagram was constructed by studying only a limited number of key alloys selected from the predicted Tb-Si phase diagram [96Bul]. Tb 5 Si 3 , Tb 5 Si 4 , TbSi, TbSi 2-b and TbSi 2-a were confirmed to exist. The Tb 5 Si 3 and TbSi intermetallics were shown to melt congruently at 1830 and 1820°C. respectively. Tb 5 Si 4 . TbSi 2- b and TbSi 2 form in peritectic reactions at 1775, 1638 ± 4 and 1517 ± 3°C, respectively. The eutectic reactions occur at 1110, 1752 ± 2 and 1222 ± 6 C. Compositions of eutectic mixtures for the first and the third ones were not specially determined. Composition of the second one was estimated to be at 48 to 49 at.% Si. The Tb-Si diagram resulting from this investigation corresponds well to the predicted one.

Terbium-silicon system

By using differential thermal analysis, metallography and X-ray examination, the La–Si phase diagram was constructed. La5Si3, La3Si2, La5Si4, LaSi were confirmed. Two lanthanum disilicides were found — LaSi2-a1 (structure type α-GdSi2) and LaSi2-a2 (structure type α-ThSi2), the two-phase region LaSi2-a1+LaSi2-a2 being very narrow. The LaSi and LaSi2-a1 intermetallics melt congruently at 1620 and 1730°C, respectively. La5Si3, La3Si2, La5Si4 and LaSi2-a2 form in peritectic reactions at 1260, 1470, 1570 and ∼1600°C, respectively. Three eutectics occur at 722±9 (11 at.% Si), 1528±9 (55.5 at.% Si) and 1205±7°C (82 at.% Si).

P. A. Saltykov

Papers

Thermodynamic modeling of oxidation of Al–Cr–Ni alloys

Lanthanum–silicon system

Cerium–silicon system

Terbium-silicon system

Lanthanum—Silicon System.