A sharp interface technique is employed to study the interaction of a solid-liquid interface in a solidifying binary alloy with a ceramic particle in the melt. The application targeted is solidification of a metal-matrix composite. A level-set based sharp interface numerical method is used to study the directional solidification process in the presence of the particle. The transport of solute and heat are computed. The directional solidification calculations are first validated against stability theory. The Mullins-Sekerka stability spectrum is reproduced with good agreement with the theory. The interaction of the cellular interface with a ceramic particle in the melt is then computed. It is shown that, in contrast to the case of a pure material, the ratio of thermal conductivity of the particle to the melt plays no role in determining the front morphology and the result of the particle-front interaction. The diffusion of species controls the evolution of the phase front around the particle. The implications of the results for particle-front interactions in a binary alloy are discussed. (C) 2007 Elsevier Ltd. All rights reserved.