Dual coating process for a high functional reinforcement phase in metal matrix composites

Abstract

An inoculant, ferrosilicon, was used as a core particle for the fabrication of a reinforcement phase, which has been generally used in the foundry industry to improve crystal growth of carbon and to restrict formation of cementite. Titanium carbide (TiC) particles were coated onto the surface of the inoculant using an inorganic binder converted into the glass phase by the hydrolysis and condensation reactions. The TiC-coated inoculant was coated again with a nickel (Ni) phase by the attractive force between Ni ions and TiC particles. The coating efficiency and morphology have been investigated with the particle size of TiC and the concentration of Ni precursor. In the case of 1 μm TiC particles, the Ni particles are homogeneously dispersed and coated on the surface of TiC particles without any self-aggregation of Ni particles. When particle size is decreased to 0.02 μm or increased to 4 μm, the Ni particles are mutually aggregated or localized on the surface of TiC particles, respectively. The amount of Ni phase on the TiC-coated inoculant increases upon increasing the concentration of Ni precursor. The reinforcement phase has been successfully prepared through the dual coating process, with an expected increase in the mechanical properties of the matrix owing to the improvement in dispersibility.