Titanium-based surface

Tambasco de Oliveira P, Nanci A. Nanotexturing of titanium-based surfaces upregulates expression of bone sialoprotein and osteopontin by cultured osteogenic cells. Biomaterials... 

On the one hand, high chromium steel polished surfaces can be used as a surface protection. On the other hand, hard chrome plating with a thickness of approx. 0.005 mm is used as the most common and least expensive coating for elastomer molds. Currently, a coating based on chromium nitride is increasingly used. In addition to these coatings, numerous other options can be considered, such as ceramic coatings or titanium-based surfaces. 

The activity of titanium based catalysts for the oxidation of organic compounds is well known. Wulff et al. in 1971 [1] patented for Shell Oil a process for the selective epoxidation of propylene with hydroperoxides like ethylbenzene hydroperoxide (EBH) or tertiary-butyl hydroperoxide (TBH) with the use of a catalyst made of Ti02 deposited on high surface area Si02. A Shell Oil plant for the production of 130,000 tons/y of propylene oxide at Moerdijk, Holland, is based on this technology. 

In the present endeavour a titanium based inorganic ion exchanger titanium tungstate (TiW) has been used as a support onto which [CuCNHjlJ has been anchored. The support (TiW) and the catalyst (CuT-TiW) have been characterised for elemental analysis, t.g.a., ft.i.r., e.s.r., reflectance spectroscopy and surface area measurements. The catalytic activity has been studied for the disproportionation of hydrogen peroxide at different temperatures, different concentrations of hydrogen peroxide and different amounts of the catalyst. 

In summary, the TS-1 catalyzed epoxidation of propylene with H2O2 to PO is a thoroughly investigated epoxidation reaction. The oxidation chemistry is well known by now, and the catalyst, and the process parameters have been optimized. Currendy, the titanium-based catalyst is in the process of being commerciahzed. Computational chemistry has been appHed to elucidate the details of the surface chemistry and to identify the important reaction steps at this point, various competing mechanisms, proposed by different authors, can be found in the literature. 

Coatings do not have the durability of the coated titanium-based anodes. However, they are less expensive, easier to apply and can be repaired and maintained easily. They are not suitable for continuously wetted abraded or trafficked surfaces. They require excellent surface preparation to get good adhesion. 

Researchers in Germany claim that a titanimn-based surface coating can cut plasticiser migration from flexible PVC products. The University of Erlangen has co-operated with GfE Medizintechnik to develop an inert, biocompatible 30 nm titanium based system called MigraStop to prevent phthalate migration in medical equipment. 

In the past few decades, many methods such as physical machining and controlled oxidation have been used to improve the in vivo osseointegration of titanium-based implants. Calcium phosphate—based thin films such as HA have been used frequently on orthopaedic implants. As a new concept in tissue engineering, it has been suggested that HA has distinct luminescence properties allowing rapid identification of phase distribution of biomimetic apatite thin films. In a research smdy, Sepahvandi et al. reported that the photoluminescence property can be used in the characterization and early detection of biomimetic bonelike apatite formation on the surface of alkaline-treated titanium implants (in SBF solution). 

As stated in the introduction, Ta coating may be used as substrate in the preparation of DSA oxygen electrodes it consists of a thin and porous layer of Iridium oxide, which acts as catalyst, obtained by thermal oxidation of an iridium compound on a valve metal. The lifetime of the anode in water electrolysis in extreme conditions of polarization (anodic current = 50 A/m ), acid concentration (30% m/m) and temperature (T = 80°C) is sensitive to the corrosion resistance of the valve metal This is shown on table I [24], which standardized life time (lifetime reported for the mass surface density of the catalyst Ir02) for some varieties of titanium base alloys and a tantalum coating as substrate ... 

Mendes VC, Moineddin R, Davies JE. Discrete calcium phosphate nanoctystalline deposition enhances osteoconduction on titanium-based implant surfaces. J Biomed Mater Res A 2009 90A 577-85. 

NBE-PEO macromonomers providing two distinct properties. Gentamicin (GS)-terminated macromonomer 18b aimed to provide antibiotic properties in an acidic medium, while carboxylic acid-terminated macromonomer 18c enabled the grafting of the nanoparticles onto biomaterial surface. After the transfer of the particles in water, the controlled release of GS at acidic pEl was demonstrated by breakage of the imine bond as well as by the efficient antibacterial activity using S. epidermidis as the bacterial strain. Scheme 2.7. These double-functionalized nanoparticles were grafted onto a titanium-based alloy, which is a preferred biomaterial for bone implants because of its biocompatibility, mechanical strength, and corrosion resistance [32]. The particles were covalently linked... 

Knee-joint prostheses consist of two metal components that replace the destroyed joint surfaces of the thigh bone (femur) and the shinbone (tibia) and that are usually cast from cobalt- or titanium-based alloys. The tibia part is typically extended by a short stem, anchoring the system in the marrow cavity. A UHMWPE insert is used as the articulating counterpart to optimize sliding behavior and to minimize wear see Fig. 8.6. 

The materials currently used in the production of medical devices include stainless steels, cobalt-base alloys, titanium-base alloys, platinum-base alloys, and nickel-titanium alloys. Steels were the first modern metallic alloys to be used in orthopedics and initial problems with corrosion were overcome by modifying the composition of the steel with the addition of carbon, chromium, and molybdenum. Carbon was added at low concentrations (ca. 0.03-0.08%) to initiate carbide formation, while the addition of chromium (17-19%) facilitated the formation of a stable surface oxide layer and the presence of molybdenum (2.0-3.0%) was found to control corrosion. The compositions of stainless steels used can vary widely. Table V shows the limits for the chemical compositions of three different alloys containing eleven different elements together with the mechanical properties for the samples after annealing and cold working. 

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