Carbon in titanium

Alloy composition, interstitial oxygen, nitrogen and carbon in titanium SCC of a and ot-fi alloys Methanolic halide solutions Hot salt SCC... 

Table V-2 Fluxing agents used for the analysis of carbon in titanium...

Elwell and Wood (39) use the conductometric determinatio of carbon dioxide to determine carbon in titanium and zirconium. The combustion is carried out similarly as in their gravimetric method. The reproducibility is + 10 /ig/g at the 200 g/g level. 

The methods (26)(27) already discussed under carbon in titanium and zirconium are claimed to be succesful for the refractory metals as well. Vasilevski et al. (27) report that a sensitivity of 1 Mg/g for carbon in tungsten, molybdenum and niobium can be obtained with samples of 1 g. Natanson et al. (38) analyzed tantalum, niobium and molybdenum in a similar way and report a sensitivity of 6 t g/q. An advantage is that compact samples can be analyzed without problems. 

The extraction of titanium is still relatively costly first the dioxide Ti02 is converted to the tetrachloride TiCl4 by heating with carbon in a stream of chlorine the tetrachloride is a volatile liquid which can be rendered pure by fractional distillation. The next stage is costly the reduction of the tetrachloride to the metal, with magnesium. must be carried out in a molybdenum-coated iron crucible in an atmospheric of argon at about 1100 K ... 

Other pigments are consumed in considerably smaller amounts. Moreover, the market data for these pigments are not as readily available as those for carbon blacks, titanium dioxide, and iron oxides. 

Alkaline-Earth Titanates. Some physical properties of representative alkaline-earth titanates ate Hsted in Table 15. The most important apphcations of these titanates are in the manufacture of electronic components (109). The most important member of the class is barium titanate, BaTi03, which owes its significance to its exceptionally high dielectric constant and its piezoelectric and ferroelectric properties. Further, because barium titanate easily forms solid solutions with strontium titanate, lead titanate, zirconium oxide, and tin oxide, the electrical properties can be modified within wide limits. Barium titanate may be made by, eg, cocalcination of barium carbonate and titanium dioxide at ca 1200°C. With the exception of Ba2Ti04, barium orthotitanate, titanates do not contain discrete TiO ions but ate mixed oxides. Ba2Ti04 has the P-K SO stmcture in which distorted tetrahedral TiO ions occur. 

Barium titanate is usually produced by the soHd-state reaction of barium carbonate and titanium dioxide. Dielectric and pie2oelectric properties of BaTiO can be affected by stoichiometry, micro stmcture, and additive ions that can enter into soHd solution. In the perovskite lattice, substitutions of Pb ", Sr ", Ca ", and Cd " can be made for part of the barium ions, maintaining the ferroelectric characteristics. Similarly, the TP" ion can partially be replaced with Sn +, Zr +, Ce +, and Th +. The possibihties for forming solution alloys in all these stmctures offer a range of compositions, which present a... 

Mineral fillers are used for light-colored compounds. Talc has a small particle size and is a semireinforcing filler. It reduces air permeabihty and has htde effect on cure systems. Calcined clay is used for halobutyl stoppers in pharmaceutical appHcations. Nonreinforcing fillers, such as calcium carbonate and titanium dioxide, have large particle sizes and are added to reduce cost and viscosity. Hydrated siUcas give dry, stiff compounds, and their acidity reduces cure rate hence, their content should be minimized. 

Various additives and fillers may be employed. Calcium carbonate, talc, carbon black, titanium dioxide, and wollastonite are commonly used as fillers. Plasticizers are often utilized also. Plasticizers may reduce viscosity and may help adhesion to certain substrates. Thixotropes such as fumed silica, structured clays, precipitated silica, PVC powder, etc. can be added. Adhesion promoters, such as silane coupling agents, may also be used in the formulation [69]. 

The addition of a more passive metal to a less passive metal normally increases the ease of passivation and lowers the Flade potential, as in the alloying of iron and chromium in 10 wt. % sulphuric acid (Table 10.31) . Tramp copper levels in carbon steels have been found to reduce the corrosion in sulphuric acid. Similarly 0 -1 palladium in titanium was beneficial in pro-... 

We have developed a compact photocatalytic reactor [1], which enables efficient decomposition of organic carbons in a gas or a liquid phase, incorporating a flexible and light-dispersive wire-net coated with titanium dioxide. Ethylene was selected as a model compound which would rot plants in sealed space when emitted. Effects of the titanium dioxide loading, the ethylene concentration, and the humidity were examined in batches. Kinetic analysis elucidated that the surface reaction of adsorbed ethylene could be regarded as a controlling step under the experimental conditions studied, assuming the competitive adsorption of ethylene and water molecules on the same active site. 

Common pollutants in a titanium dioxide plant include heavy metals, titanium dioxide, sulfur trioxide, sulfur dioxide, sodium sulfate, sulfuric acid, and unreacted iron. Most of the metals are removed by alkaline precipitation as metallic hydroxides, carbonates, and sulfides. The resulting solution is subjected to flotation, settling, filtration, and centrifugation to treat the wastewater to acceptable standards. In the sulfate process, the wastewater is sent to the treatment pond, where most of the heavy metals are precipitated. The precipitate is washed and filtered to produce pure gypsum crystals. All other streams of wastewater are treated in similar ponds with calcium sulfate before being neutralized with calcium carbonate in a reactor. The effluent from the reactor is sent to clarifiers and the solid in the underflow is filtered and concentrated. The clarifier overflow is mixed with other process wastewaters and is then neutralized before discharge. 

In the titanium dioxide production plant where the chlorine process is employed, the wastewater from the kiln, the distillation column, bottom residue, and those from other parts of the plant first settle in a pond. The overflow from this pond is neutralized with ground calcium carbonate in a particular reactor, while the scrubber wastewater is neutralized with lime in another reactor. The two streams are sent to a settling pond before being discharged. 

Table 7 Calculated filler levels of calcium carbonate and titanium dioxide based on the ICP results in Table 5...

Table 7 shows the calculated weight percent of calcium carbonate and titanium dioxide in the white-colored paint sample. These levels are based on the calcium and titanium levels shown in Table 6. Calcium carbonate was evident by the FTIR spectrum acquired from the dried paint sample, shown in Figure 13. (Flad it been available, Raman spectroscopy, which gives ready access to the low wavenumber region, could have been used to confirm the presence (and polymorphic form) of titanium dioxide [4].) Given the white color of the paint, it is likely that the titanium present was present as titanium dioxide, and this was assumed in the calculations. The calculated weight percentage of calcium carbonate in the dried paint is 21.7 wt%, and 12.6 wt% in the paint containing the solvents. The titanium dioxide levels were calculated to be 30.6 and 17.7 wt% in the dried and solvent-containing paint sample, respectively.

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