Jin et al. Nanoscale Research Letters 2011, 6:515 http://www.nanoscalereslett.com/content/6/1/515 N A N O E X P R E S S Open Access Self-propagating high-temperature synthesis of nano-TiC particles with different shapes by using x carbon nano-tube as C source Shenbao Jin1,2, Ping Shen1,2, Dongshuai Zhou1,2 and Qichuan Jiang1,2* Abstract With using the carbon nano-tube (CNT) of high chemical activity, nano-TiCx particles with different growth shapes were synthesized through the self-propagating high temperature in the 80 wt.% metal (Cu, Al, and Fe)-Ti-CNT systems. The growth shapes of the TiCx particles are mainly octahedron in the Cu- and Al-Ti-CNT systems, while mainly cube- and sphere-like in the Fe-Ti-CNT system. Keywords: self-propagating high-temperature synthesis (SHS), carbon nanotubes, nano-TiCx particles Introduction As known, some ceramic particles, such as titanium car- bide (TiCx), are usually used as the reinforcing phases in the composites due to their unique properties such as high melting point, extreme hardness, and high resistance to corrosion and oxidation. Recently, many experimental and theoretical studies have indicated that decreasing the sizes of the reinforcing ceramic particulates can lead to substantial improvements in mechanical performance of the composites [1-11]. For example, Ma et al. [11] showed that the tensile strength of 1 vol.% Si3N4 (10 nm)/Al com- posite is comparable to that of the 15 vol.% SiCp (3.5 μm)/ Al composite, and the yield strength of the former is much higher than that of the latter. Then, with signifi- cantly increasing intention to develop nanoparticle-rein- forced composites with superior mechanical properties, the demand for nano-sized ceramic powders, including TiCx, has become more urgent. Among the variety of the preparation methods for TiCx, self-propagating high-temperature synthesis (SHS) is noted by us because it is a convenient and efficient way to synthesize TiCx. However, the SHS is quite chal- lenging to produce the nano-sized ceramic particles because the combustion temperature will lead to consid- erable coarsening of the ceramic particles. At present, * Correspondence: jqc@jlu.edu.cn 1Key Laboratory of Automobile Materials, Ministry of Education, People’s Republic of China Full list of author information is available at the end of the article the usual method for synthesizing the nano-ceramic par- ticles through the SHS is the addition of volatile diluents such as NaCl into the reactants. Some nano-ceramic particles such as TiB2 and ZrB2 have been prepared by adding NaCl to the SHS reactants [12-14], and the nano-TiCx particles (20 to 100 nm) were also obtained by Nersisyan et al. [15] in the 30 wt.% NaCl-Ti-carbon black system. On the other hand, the addition of a second metal (Me) such as Al, Cu, and Fe can also decrease the combustion temperature and thus prevent the ceramic particles from further growth. For example, with the increase in the Al incorporation from 10 to 40 wt.%, the sizes of the TiCx particles decrease from about 3 μm to 400 nm [16]. How- ever, when more Me (≥50 wt.%) is incorporated, the SHS reaction tends to be incomplete or even cannot be ignited. Generally, this situation can be improved through using finer C-source particles because they can enlarge the area of the contact surface between the liquid and the carbon source and decrease the activation energy of the SHS reac- tion. At present, the source of C that are mostly used dur- ing the SHS are graphite (typically 1 to 150 μm) and C black (< 100 nm). In contrast to them, carbon nano-tube (CNT) has much finer size, usually 5 to 20 nm in dia- meter. In fact, CNT has been used to synthesize the nanostructured TiC-TiB2 [17] and carbide nanofibers [18] during the SHS. In this paper, taking advantage of high chemical activ- ity of the CNT, we tried to prepare the nano-sized TiCx © 2011 Jin et al; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.