Synthesis of Fe–TiC–Al 2 O 3 hybrid nanocomposite via carbothermal reduction enhanced by mechanical activation Mansour Razavi a, * , Amir Hossein Rajabi-Zamani a , Mohammad Reza Rahimipour a , Reza Kaboli b , Mohsen Ostad Shabani a,c , Rahim Yazdani-Rad a a Department of Ceramic, Materials and Energy Research Center (MERC), P.O. Box 14155-4777, Tehran, Iran b Department of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, 38678 Clausthal-Zellerfeld, Germany c Department of Materials Science and Engineering, Sharif University of Technology (SUT), P.O. Box 11365-9466, Tehran, Iran Received 9 February 2010; received in revised form 6 August 2010; accepted 2 September 2010 Available online 29 September 2010 Abstract In this study, the feasibility of the synthesis of Fe–TiC–Al 2 O 3 hybrid nanocomposite via mechanical activation followed by carbothermal reduction was investigated. The raw materials including ilmenite, carbon black and aluminum powder were milled in a high energy planetary ball mill. At different time intervals, samples were taken for characterization. After phase evaluation with XRD, some samples were heat treated in an atmosphere controlled tube furnace. Studies proved that increasing the milling time of the raw materials resulted in the formation of more amorphous phase and more active materials. Furthermore, investigations showed that after carbothermal reduction, the synthesized TiC crystallites were in the scale of nanometers and the lattice parameter had some deviation from the standard value. At higher heat treatment temperatures, the crystallite sizes increased, while the deviation from the standard lattice parameter decreased. # 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Keywords: Hybrid nanocomposite; Mechanical activation; Titanium carbide; Ilmenite 1. Introduction The existence of hard ceramics in the rather soft metallic matrix has made metal matrix composites (MMCs) interesting materials [1,2]. Among MMCs, despite high density, ferrous matrix composites are still desirable due to easy and inexpensive production in addition to more isotropic properties [3]. The properties of a composite are determined by the characteristics of the reinforcing phase and also the compat- ibility of this phase with the matrix. Consequently, the production of a hybrid composite including a combination of several types of reinforcing materials can result in unique mechanical and wear properties [4–7]. Among common reinforcing phases, TiC with the crystal structure of NaCl is desirable due to its high hardness, low density, high melting point, high elastic modulus, excellent wear and corrosion resistance, proper electrical conductivity, high thermal shock resistance, good wettability and stability in iron melt [8–12]. These composites can be produced via different methods including HP, HIP, SHS and infiltration. Using common methods often result in the production of big agglomerates obstructing the distribution of the secondary phase in the matrix. Additionally, long time periods and high temperatures of these methods cause the appearance of large crystallites. Mechanical synthesis activation (MSA), which is nowadays used for the production of a wide range of nanocrystalline compositions and amorphous phases, reduces the time and temperature of the reaction as well as increasing the production rate, in comparison with common routes. In this method, during milling process, a portion of the energy of the ball mill is transferred to the powder causing reduction in the crystallite sizes in addition to increase in the crystal defects including dislocations, structural distortion and atom dis- placement. All the above bring about more activation of the material, which can greatly stimulate the kinetics of the reaction [13–17]. Several researchers have taken advantage of this method to raise the speed of leaching, thermal processes www.elsevier.com/locate/ceramint Available online at www.sciencedirect.com Ceramics International 37 (2011) 443–449 * Corresponding author. Tel.: +98 261 6204131; fax: +98 261 6201888. E-mail addresses: m-razavi@merc.ac.ir, m7816006@yahoo.com (M. Razavi). 0272-8842/$36.00 # 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved. doi:10.1016/j.ceramint.2010.09.013