Titanium-carbon-nitrogen system

Solid-state diffusion of carbon, nitrogen, or both carbon and nitrogen, into titanium powders at high temperatures (1270-1770 K) where the reaction takes place over the course of several hours.8-12 TiCN can also be produced by sintering a mixture of TiC and TiN 13 or by solid-state diffusional reactions in the systems of TiC + N2, TiN + C, and Ti + C + N2.14,15... 

The boundary between hardmetals and cermets is not strict because many of these compacts resemble microstructure features of both type of materials [106] faceted WC crystals together with round-shaped titanium carbonitride-based hard particles. Generally, these titaniiun carbonitride hardmetals are comparable with respect to properties and microstructure to WC-based hardmetals. The powders of these materials are liquid phase sintered with Ni or Ni-Co binder metal alloys. The core-and-rim structure of the hard phase usually exhibit a molybdenum- and carbon-rich (Ti,Mo)C rim and a titanium- and nitrogen-rich Ti(C,N) but can also be inverted (compare Fig. 26). The metallurgy of the phase reactions is (because of the complexity of the multicomponent system) not yet fully understood [69]. 

Intramolecular addition of amine N-H bonds to carbon-carbon multiple bonds would afford nitrogen heterocycles. To realize catalytic cyclization of a,co-aminoalkenes or aminoalkynes, various catalytic systems have been developed especially with early transition metals such as titanium, zirconium, lanthanide metals, and actinide metals [ 12], Late-transition-metal catalysis based on Ni, Pd, and Rh has also proved to be efficient [ 12], Recently, the ruthenium-catalyzed intramolecular hydroamination of aminoalkynes 15 was reported to afford 5-7-membered ring products 16 in various yields (Eq. 6) [13]. Among... 

Mechanochemical processing has been used to manufacture nanocrystalline powders of nitride and carbide ceramics. The majority of systems involve milling of the metal precursor with a source of carbon or nitrogen. The source of carbon or nitrogen has typically taken the form of the element itself. However, a variety of other reagents have also been used. For example, Zhang et al. reported the synthesis of titanium nitride by milling titanium metal with pyrazine in a benzene solution. 

Aluminum, boron, carbon, iron, nitrogen, oxygen, phosphorus, sulfur and titanium are the common impurities in the SoG-Si feedstock. Arsenic and antimony are frequently used as doping agents. Transition metals (Co, Cu, Cr, Fe, Mn, Mo, Ni, V, W, and Zr), alkali and alkali-earth impurities (Li, Mg, and Na), as well as Bi, Ga, Ge, In, Pb, Sn, Te, and Zn may appear in the SoG-Si feedstock. A thermochemical database that covers these elements has recently been developed at SINTEF Materials and Chemistry, which has been designed for use within the composition space associated with the SoG-Si materials. All the binary and several critical ternary subsystems have been assessed and calculated results have been validated with the reliable experimental data in the literature. The database can be regarded as the state-of-art equilibrium relations in the Si-based multicomponent system. 

Corrosion can be a problem, especially if a chlorine-containing compound is decomposed. This may require that the reactor be made of titanium. The corrosion can be reduced by the use of sodium carbonate.207 Use of this system at 380°C reduced the content of polychlorinated biphenyls in a sample from 20 mg/L to less than 0.5 /tg/L. Trichloroethylene, 1,1,1-trichloroethane, and trichloroacetic acid were destroyed with 99.96% efficiency at 450°C for 60 ss using 1.5% hydrogen peroxide plus sodium bicarbonate.208 Sodium nitrate or sodium nitrite could be used in place of the hydrogen peroxide. Nitrates, ammonium hydroxide, and amines, all are converted to nitrogen at 350-360 C. Emulsions of petroleum, water, and solids can be broken by heating to 350oC. Supercritical water has been used to recover 2,4-diamino-toluene from distillation residues from the manufacture of 2,4-toluenediisocyanate.209... 

In most efforts, the films produced were either amorphous, or their nitrogen content was less than the target of 57%. D. Li et al. [184] using a magnetron sputtering system produced crystalline carbon nitride/titanium nitride composite coatings with a reported hardness of 55 GPa. 

Another catalyst system found in the patent literature involves the deposition of halides such as zirconium tetrachloride, vanadium tetrachloride, titanium tetraiodide, or oxyhalides such as chromium oxychloride or vanadium oxychloride on a finely divided particulate inorganic substrate having surface hydroxyl groups. Among such solids are alumina, zirconia, silica (particularly a pyrogenic silica such as Cab-O-SiF ), or a carbon black such as channel black or furnace black. A toluene slurry of this material is added, under dry nitrogen, to a toluene solution of A -vinyl-pyrrolidone containing a small amount of triisobutylaluminum. After 24 hr at 80°C, a 25% yield of polymer is produced [73]. 

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