Titanium deposition

D. Ferro, S.M. Barinov, J.V. Rau, R. Teghil, A. Latini, Calcium phosphate and fluorinated calcium phosphate coatings on titanium deposited by Nd YAG laser at a high fluence, Biomaterials 26 (2005) 805-812. 

Au(lll)). For optical studies, mica or glass substrates were used, while gold/ titanium deposited onto a silicon (100) wafer was used as a substrate for time-resolved studies. 

A question of considerable interest in coal hydroliquefaction chemistry is the amount and nature of "organically bound metals in the coal. One reason for this interest is the observation that when supported metal direct conversion catalysts are used in liquefaction reactors, a primary mode of deactivation is metals deposition Q, 2). In particular, recent work at the Pittsburgh Energy Technology Center (PETC) (4,5) and elsewhere (3) has indicated very high levels of titanium deposition on supported Co Mo catalysts used in the fixed bed continuous reactor system. It has been suggested that the culprits in such deposition are soluble metal species (6 9) The analyses of a Western Kentucky (Homestead) hvBb feed coal and of material deposited between the catalyst pellets in the fixed bed reactor at PETC (4) are shown in Table I. 

In conclusion, it appears that the dialytic method, although somewhat more cumbersome than traditional soxhlet techniques, provides a coal extract which is representative of the soluble organic material in the coal and is free of particulates. Preliminary results indicate that this dialytic extract may be very useful in studies of the existence and/or nature of soluble metals in coal. Although further work is indicated, the very low metal content of the dialyzate casts some doubt on the model for titanium deposition on catalysts, which involves decomposition of a soluble organically associated metal species on the catalyst surface. 

The first uses of radiocarbon in deep-sea core dating were based on few data points and depended on extrapolation assuming the constant rate of titanium deposition (Arrhenius et al., 1951) or interpolation (Suess, 1956) for determination of rates of accumulation and chronology. The first systematic study of radiocarbon incorporating possible changes in accumulation rates with depth in a core was performed by Broecker et al. (1958). They showed that accumulation rates of both the carbonate fraction and the detrital fraction varied with time in the equatorial Atlantic and those variations were linked to paleoclimatic indicators inferred from paleontologic data (Figure 3). 

Vapour deposition experiments on titanium have shown that on increasing the rate of titanium deposition at constant argon deposition rate, three new absorptions were observed in the spectrum of the matrix in addition to those due to matrix-isolated atoms. These absorptions have been attributed to the dititanium species for which MO calculations indicate a strong 4s-4s a-interaction. ... 

Massaro, C., Baker, M.A., Cosentino, F., Ramires, P.A., Klose, S., and Milella, A. (2001) Surface and biological evaluation of hydroxyapatite-based coatings on titanium deposited by different techniques. J. Biomed. Mater. Res., 58 (6), 651 -657. 

In the study of anodized titanium oxide/titanium, commercially available polyester (Mylar) was used as the substrate with a 200-mn thick film of titanium deposited by evaporation [36], The titanium metal was anodized in generate 7- to 8-mn thick titanium dioxide films, which showed high leakage (due to Ti02 being a wide band gap semiconductor). Capacitors were made with this dielectric, and these showed a capacitance of 2.42 pFcm and an effective dielectric constant K ff = 21. 

Figure 16.16 Process sequence for contact formation (a) wafer cleaning, (b) titanium deposition, (c) high-temperature anneal leading to the formation of TiSi2, and (d) titanium etch. Cobalt can be used in place of titanium.

In this section we discuss the electronic structure of semiconductors, metals, and semiconductor-metal interfaces as determined by APS. First, we describe the APS studies on Si. Then we take the example of elemental Ti studied by DAPS, AEAPS, and SXAPS. After this, the SXAPS results on intermetallics TySfij (x=0, 0.3, 0.5, 0.7, 1.0) are discussed. These are included to give an idea of the types of information available from APS spectra. The reaction of silicon upon titanium deposition which is used as a metallization material in microelectronics is then discussed. The study also includes the effect of temperature on Ti-Si interface. Finally, the apphcations of APS for band... 

Fig. 6.37 ESEM image of the of titanium deposit at x 5,000 magnification in secondary electrons mode (above) and the EDX analysis of the surface layer (below)...

The results of the IRRAS study show that the absorption bands of the interfacial oxide layer differ substantially from those of the initial oxide on a free silicon surface, depending on the substrate temperature during the titanium deposition. Specifically, the intensity of the 1240-cm (Si02) and 1160-cm (SiO) bands decreases, and the 1240-cm peak shifts to lower frequencies. The dependence of the intensities of the absorption peaks of Si02, SiO, and TiO t on the temperature of the silicon substrate during the Ti deposition is shown in Fig. 6.1. Extrapolations to absorbances of the initial oxide layer on the free silicon surface are indicated by the dashed line. 

The form of the titanium deposit is dependent upon the filament temperature and the crystalline form of the filament itself. In Fig. 8.12, the middle bar consists of a single crystal of titanium grown upon a filament, which itself consists of a single crystal of tungsten. The upper and lower bars demonstrate the effect of filament temperature, the larger crystals being deposited at 1300 to 1400°C and the smaller ones at only 1100°C. 

Wei D., Okido M. and Oki T., Characteristics of titanium deposits by electrolysis in molten chloride-fluoride mixture,(1994), J. Appl Electrochem., 24, 923-29. 

In contrast, when small alkali ions such as lithium are introduced in the melt, oxidation state II becomes stable and disproportionation reactions appear giving rise to a colloidal precipitate together with titanium deposition. As for other refractory metals, the stability range of titanium (II) is greatly enlarged in alkali chloroaluminates. This effect is due to the... 

Fig. 6.15 SEM micrographs of gold particles on titanium deposited from (NH4)3Au(S03)2 10 mM, Na2S03 0.1 M, and C2HgN2 10 mM, at pH 6.5, at changing potential, as indicated (vs. SCE) and 50 ms pulse duration. Scale bar is 1 pm...

Titanium is an element of group 4 of the periodic table. It is in the same group as zirconium and hafnium. It has a high similarity to silicon which was the same group in the old periodic table. Titanium exists in 5600 ppm in the Earth s crust [1], it is the fourth largest element after iron, aluminium and magnesium as common use metal. The titanium deposits are approx. 340 million tons or more [2], The span of life as a metal resource is three thousand years or more, the ranking of the life of resources as practical metals is the second after iron. 

In the process of titanium deposition, high adatom surface diffusion rates, low adatom concentrations and low overpotentials favoured the building of existing crystals. Meanwhile, the low surface diffusion rates, high adatom concentrations and high overpotentials increased the formation rate of new nuclei. Clearly, the dominant parameter which affects the nucleation rate is the applied overpotential. At high overpotentials. 

The low current efficiencies can be explained by the macroscopic appearance of the titanium deposits (Figure 4.10.2). In the beginning of a series of processes many coated fibres possessed large foils grown on the surface of the electrolyte during electrolysis. This indicates that a large amount of the current had not contributed to the faradaic process, but short circuits formed on the surface of the molten salt. 

Mitrovski and Nuzzo [37] H2 Air Sulfuric add (5 M) or sodium hydroxide (2.5 M) Electrodeposited Ptor elec-trodeposited Pd on 100 nm ofPt Electrodeposited Pt or electrodeposited Pd on lOOnm of Pt PDMS lOOnm Pt on 15 nm of titanium deposited by E-beam evaporation... 

Thermally sprayed and hot isostatically pressed (HIP) coatings, including nickel and iron-base materials, with a high content of the carbides of tungsten, chromium, and titanium, deposited 5 mm (0.2 in.) or more thick... 

The lanthanides are more abundant in the Earth s crust than many better known metals. The other metals are better known in part because nature has concentrated them in forms that make their recovery economical. The lanthanides are rarely concentrated and even when they are, their chemical beneficiation is usually more costly than for competing metals. In some cases, lanthanides become available as coproducts from mining operations for other metals, e.g., placer tin and titanium deposits, uranium processing liquors. In these operations the burden of mining cost is borne by the other metals. 

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