CERAMICS INTERNATIONAL Available online at www.sciencedirect.com Ceramics International 39 (2013) 6503–6508 Fabrication and mechanical properties of metal matrix composite with homogeneously dispersed ceramic particles Eun-Hee Kim a,n , Geun-Ho Cho a , Je-Hyun Lee a , Yeon-Gil Jung a,nn , YoungSoo Yoo b , SeongMoon Seo b a School of Nano and Advanced Materials Engineering, Changwon National University, #9 Sarim-dong, Changwon, Kyungnam 641-773, Republic of Korea b High Temperature Materials Research Group, Korea Institute of Materials Science, 797 Changwondaero, Changwon, Kyungnam 641-831, Republic of Korea Received 11 January 2013; received in revised form 23 January 2013; accepted 26 January 2013 Available online 7 February 2013 Abstract Titanium carbide (TiC) particles were coated with nickel (Ni) to increase their compatibility with a metal matrix, leading to an improvement in the dispersibility of TiC particles in the molten matrix. TiC particles were dispersed into a basic aqueous solution of pH 12, and then nickel nitrate (Ni(NO 3 ) 2 ), as a Ni precursor, was added to the TiC suspension. The interaction between the TiC particles and the Ni precursor is driven by the attractive force between the Ni cations and the TiC particles with negative charge. An inoculant (ferrosilicon), which has been used in the foundry industry to improve crystal growth of graphite, was used as a core particle. The Ni-treated TiC particles were coated onto the surface of the inoculant using an inorganic binder converted into its glass phase by sol–gel reactions. The reinforcement particles prepared through the dual-coating process were then injected into the molten matrix based on iron at 1500 1C. The crystal phase of the graphite is more finely and shortly grown in the reinforced metal matrix than in that without the reinforcement particles. This means that the reinforcement particles are homogeneously and uniformly dispersed into the matrix without any aggregation of particles, implying that the mechanical properties of the reinforced matrix would be greater than those of a non-reinforced matrix. Consequently, metal matrix composites with reasonable properties can be fabricated successfully using the reinforcement particles prepared by the dual-coating process. & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Keywords: C. Hardness; Metal matrix composites (MMCs); Microstructure; Mechanical property; Reinforcement particle 1. Introduction Research into composites that incorporate ceramic particles as a reinforcement phase, namely metal matrix composites (MMCs), has aimed to enhance the wear resistance, hardness, and elasticity of pure metals [1,2]. Silicon carbide, alumina, titanium carbide (TiC), and titanium boride, all well-known ceramic materials with suitable mechanical properties, have been used as reinfor- cement phases for metal matrices. In particular, TiC has been widely used as a particulate-reinforcement phase for a matrix because of its high modulus, hardness, stiffness, and strength [3,4]. To maximize these advantageous effects of reinforcement particles in the matrix, the particles must be individually dispersed in the metal matrix without any aggregation. However, the reinforcement particles may self-aggregate both because of incompatibility between the TiC particles and the metal matrix and because of the relatively lower specific gravity of the TiC particle than that of the metal, thereby reducing the mechanical proper- ties of the matrix despite the addition of the reinforcement particles. Therefore, for the homogeneous dispersion of TiC particles within the molten metal, the TiC particles have been coated onto an inoculant used in a iron (Fe)- based matrix to improve the crystal growth of graphite and to restrict the formation of cementite. In this work, the reinforcement particles using the inoculant as a core particle were fabricated using a dual- coating process. In the first part of the process, TiC particles www.elsevier.com/locate/ceramint 0272-8842/$ - see front matter & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved. http://dx.doi.org/10.1016/j.ceramint.2013.01.082 n Corresponding author. Tel.: þ 82 55 213 2742; fax: þ 82 55 262 6486. nn Corresponding author. Tel.: þ 82 55 213 3712; fax: þ 82 55 262 6486. E-mail addresses: udam99@changwon.ac.kr (E.-H. Kim), jungyg@changwon.ac.kr (Y.-G. Jung).