Size Effect in Ni-Coated TiC Particles for Metal Matrix Composites

Abstract

Nickel (Ni) particles have been coated on the surface of titanium carbide (TIC) particles to enhance the dispersion of TiC particles into a molten metal and to achieve an improvement in the mechanical and thermal properties of the metal matrix. The adhesion of Ni particles on the surface of TiC particles is induced by the attractive force between the TiC with a negative charge and the Ni cation in an aqueous solution. The powders prepared with the relatively large particle sizes of 1, 4, and 40 mu m show both TiC and Ni phases, whereas that prepared with a particle size of 0.02 mu m shows complex phases of Ni, TiC, and TiO2 (titanium dioxide). The TiO2 phase is caused by the oxidation reaction between the TiC and oxygen. The 1 mu m powder shows that the Ni is located only around the TiC without any self-aggregation and the TiC and Ni particles are isolated in the 4 and 40 mu m powders, as confirmed in TEM images. The particle size is the essential factor in fabricating highly efficient Ni-coated TiC particles for metal matrix composites.