Titanium deposition, metallic

Anode Applications. Graphite has been used as the primary material for electrolysis of brine (aqueous) and fused-salt electrolytes, both as anode and cathode. Technological advances, however, have resulted in a dimensionally stable anode (DSA) consisting of precious metal oxides deposited on a titanium substrate that has replaced graphite as the primary anode (38—41) (see Alkali and chlorine products). 

In the field of electrowinning and electrorefining of metals, titanium has an advantage as a cathode, upon which copper particularly can be deposited with finely balanced adhesion that allows the electrodeposited metal to strip easily when required. Titanium anodes are also being employed as a replacement for lead or graphite in the production of electrolytic manganese dioxide. 

Investigation into the effect has been mainly devoted to reactions with red fuming nitric acid . It seems that in red fuming nitric acid a preliminary reaction results in the formation of a surface deposit of finely divided metallic titanium ignition or pyrophoricity can then be initiated by any slight impact or friction. The tendency to pyrophoricity increases as the nitrogen dioxide content of the nitric acid rises from zero to maximum solubility at about 20%, but decreases as the water content rises, the effect being nearly completely stifled at about 2% water. 

A mercury cathode finds widespread application for separations by constant current electrolysis. The most important use is the separation of the alkali and alkaline-earth metals, Al, Be, Mg, Ta, V, Zr, W, U, and the lanthanides from such elements as Fe, Cr, Ni, Co, Zn, Mo, Cd, Cu, Sn, Bi, Ag, Ge, Pd, Pt, Au, Rh, Ir, and Tl, which can, under suitable conditions, be deposited on a mercury cathode. The method is therefore of particular value for the determination of Al, etc., in steels and alloys it is also applied in the separation of iron from such elements as titanium, vanadium, and uranium. In an uncontrolled constant-current electrolysis in an acid medium the cathode potential is limited by the potential at which hydrogen ion is reduced the overpotential of hydrogen on mercury is high (about 0.8 volt), and consequently more metals are deposited from an acid solution at a mercury cathode than with a platinum cathode.10... 

Hydrogen reduction has a major advantage in that the reaction generally takes place at lower temperature than the equivalent decomposition reaction. It is used extensively in the deposition of transition metals from their halides, particularly the metals of Groups Va, (vanadium, niobium, and tantalum) and Via (chromium, molybdenum, and tungsten). The halide reduction of Group IVa metals (titanium, zirconium, and hafnium) is more difficult because their halides are more stable. 

Ousi-Benomar, W. Xue, S. S. I. cssard, R. A. Singh, A. Wu, Z. L. Kuo, P. K. 1994. Structural and optical characterization of BaTi03 thin films prepared by metal-organic deposition from barium 2-ethylhexanoate and titanium dimethoxy dineodecanoate. J. Mat. Res. 9 970-979. 

Aluminum, copper, nickel, and their alloys unalloyed titanium A-6 (a) No additional requirements A-6 (b) No additional requirements unless filler metal composition is outside the range for base metal composition then test per column B-6 B-6 Designer shall be assured by suitable tests [see Note (4)] that base metal, weld deposits, and HAZ are suitable at the design min. temp. 

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. 

Solutions containing the metal, most commonly in nitric acid, will deposit the metal on a platinnm electrode by electrodeposition. Polonium metal is deposited spontaneously from such solutions on to metals such as silver or nickel. The metal can be sublimed off such support metals at low pressures. Thermal decomposition of polonium sulfide also yields the metal. In much the same way as tellurium, the metal can be obtained from its solutions by the action of reducing agents such as hydrazine, tin(II) ion, titanium(III) ion, and dithionite. Such metal precipitates appear as gray-black powders. Thin foils, silvery in color, have been prepared by vacuum sublimation of the metal. 

Most metals can be electrolytically deposited from water-free melts of the corresponding metal salts. It is well known that aluminum, lithium, sodium, magnesium, and potassium are mass produced by electrolytic deposition from melts. Industrial processes for the melt-electrolytic production of beryllium, rare earth metals, titanium, zirconium, and thorium are also already in use. Pertinent publications [74, 137, 163] describe the electrolytic deposition of chromium, silicon, and titanium from melts. Cyanidic melts are used for the deposition of thick layers of platinum group metals. It is with this technique that, for instance, adhesion of platinum layers on titanium materials is obtained. Reports concerning the deposition of electrolytic aluminum layers [17, 71-73, 94, 96, 102, 164, 179] and aluminum refinement from fused salts [161] have been published. For these processes, fused salt... 

Anatase deposits with a Ti02 content of 30 to 40% have been discovered in Brazil. They contain 220 10 t Ti02, being more titanium dioxide than in all the currently known rutile deposits. It can possibly be used as a starting material for TiCl4 in the production of Ti02 pigments or in the production of metallic titanium. 

We can see Cb values for lead, zinc, tin, nickel, and copper are an order of magnitude higher than those for zirconium, titanium, and vanadium. We can observe also that the curves follow a similar pattern independently of the composition of the bedrock, diabasis orgneissic, underlying the forest ecosystems. Simultaneously, various plants absorb the same elements at a different rate. For instance, mosses are better accumulators of poorly absorbed metals, like Ti, Zr, V, than tree and small shrubs. The selective accumulation of metals by plants can be used in prospecting for trace metal ore deposits. 

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. 

S. Kasaoka and H. Nanba, "Effect of Alkali Earth Metal Salt Deposition on Catalytic Activity of Vanadium Pentoxide/Titanium Dioxide in Nitric Oxide Reduction with Ammonia", Nenryo Kvokaiski. Japan, 1984, i(6), 403-412. 

It is usually assumed that the metal is deposited on an electrode that must be replaced during the process, and that the anode is insoluble. The anodic reaction is oxidation of water to oxygen and/or oxidation of anions, e.g. CN. For aqueous solutions with a low salinity, titanium anodes coated with TiO and IrO or with platinum are mostly used. 

First, a thin barrier layer of titanium is deposited by PVD on the wafer to line the bottom and the inside walls of the via-1 holes. The titanium serves to improve the adhesion of the tungsten plug to the ILD-1 oxide. Next, titanium nitride (TiN) is immediately deposited over the titanium as a diffusion barrier for the tungsten metal. Then, tungsten metal is deposited by CVD to fill the via-1 holes and coat the entire wafer. Finally, the tungsten is polished down to the upper surface of... 

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... 

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