TiC single crystal

C. H. Chen, Y. Xuan, and S. Otani, Temperature and Loading Time Dependence of LaB6, YB6 and TiC Single Crystals, Jour. Alloys and Compds., 350, L4... 

Y Kumashiro, A Itoh, T Kinoshita, M Sobajima. The micro-Vickers hardness of TiC single crystals up to 1500°C. J Mater Sd 12 595, 1977. 

Y Kumashiro, A Itoh, S Misawa. TiC single crystals prepared by the radio frequency floating zone process. J Less Common Met 32 21, 1973. 

F Yajima, T Tanaka, H Bannai, H Kawai. Preparation of TiC, single crystal with homogeneous compositions. J Cryst Growth 47 493, 1979. 

S Otani, S Honma, T Tanaka, Y Ishizawa. Preparation of TiC, single crystals with maximum carbon content by a floating zone technique. J Cryst Growth 61 1, 1983. 

S Otani, T Tanaka, Y Ishizawa. Growth conditions of high purity TiC single crystal using the floating zone method. J Cryst Growth 92 8, 1988. 

The EE patterns are related to the tip shape change. The tip shape becomes a polyhedron composed of the (100) and (111) planes after flash heating above 1500° C, because the surface energy of the (100) and (111) planes in TiC is relatively low compared with those of other crystal planes (32). The polyhedral shape of the tip was directly confirmed by field ion microscopy (EIM) studies of a TiC single crystal (14). The tip has several sharp points on the top, which are indicated by letters A and B in Eig. 2b and d. Points A and B correspond to bright spots of emission patterns. Therefore, observed emission patterns can be interpreted in terms of emissions from strong electric field portions of the tip. This interpretation is consistent with the insensitivity of the EE patterns to exposures such as oxygen as explained earlier. 

K Senzaki, Y Kumashiro. Field emission studies of TiC single crystal. Jpn J Appl Phys Suppl 2 Pt 1 289, 1974. 

Y Kumashiro, H Shimizu, A Itoh. Electron emission characteristics and surface states of carbide emitters—TiC single crystal and other transition metal carbides. Oyo Buturi 45 607, 1976 (in Japanese). 

K Kawasaki, K Senzaki, Y Kumashiro, A Okada. Energy distribution of field-emitted electrons from TiC single crystal. Surf Sci 62 313, 1977. 

H Adachi, K Fujii, S Zaima, Y Shibata, S Otani. Flashing temperature dependence of field electron emission from TiC single crystals. J Vac Soc Jpn 27 658, 1984 (in Japanese). 

Even though TiC is much harder than WC at room temperature (3200 kg/mm for TiC, vs 1800 kg/mm for WC), at higher temperatures, TiC oxidi2es and loses its hardness rapidly. Figure 17 is a plot of the variation of hardness of single crystals of various monocarbides with temperature (44). No similar data is available for multicarbides or other refractory hard materials, such as nitrides, borides, oxides, or any combination of them. 

This reaction is usually carried out at a temperature range of850-1050°C in a hydrogen atmosphere and at pressure varying from less than 1 Torrto 1 atm. Above 1300°C, single crystal TiC isdeposited.P H" Other carbon sources, such as toluene and propane, have also been used.t ] Reaction (1) is also used in a plasma at a lower temperature range (700-900°C) and lower pressure (1 Torr).b 2]... 

The sol-gel process to prepare SIO2 glass fibers and T102 films has been reviewed. It has been known that the hydrolysis conditions such as molar ratio of water to alkoxide and reaction temperature are critical to the desired forms of the gel product (fiber, film or bulk). Some properties of the resultant products have been examined. Especially, Ti02 films have been attempted to use as a photoanode for decomposition of water, and their photoelectrochemical properties are described in comparison with the results previously obtained for single crystal and polycrystalline TiC>2, and are discussed in terms of the microstructure of the film. 

This is comparable to or slightly higher than the values reported for single crystal (11) and polycrystalline Ti02 (12), and much higher than those for the TiC>2 film electrode prepared by other methods such as chemical vapor deposition (13) and oxidation (14) and anodization (15) of Ti metal. The high efficiency of the dip-coated Ti(>2 film may be attributed to the porous nature of the film as described below. 

Dynamic atomic-resolution ETEM and diffraction studies provide fundamental insights into the catalyst precursor transformation mechanism. The studies reveal that the temperature regimes are critical to the formation of active catalysts. They show that the nature of the VHPO -> VPO transformation is topotac-tic. Topotaxy is defined as the conversion of a single crystal to a pseudomorph... 

The TiC>2 samples, mounted in a helium cryostat (10-300 K), are lmm-thick (001) and (110)-cut single crystals to study the electronic response with the (THz) electric field perpendicular ( L) and parallel (//) to the c axis, respectively. Rutile is the most common and stable TiC>2 polymorph and has a tetragonal structure with a=4.6A and c=2.9A. The band gap of rutile is 2.9 eV at room temperature, increasing slightly at lower temperatures. 

Carbides, Silicides, and Germanides. Single crystals of TiC were obtained from the reaction... 

A disc of reduced semiconducting rutile crystal 2 cm in diameter and 2 mm thick is heated in air for 10 s at 300 °C. After cooling, circular electrodes, lcm in diameter, are applied symmetrically to the two major surfaces. The chemical diffusion coefficient D for the oxidation reaction in reduced single-crystal TiC is given by... 

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