Patent ID: 7610945
Filing Date: 2009-11-03
Classification: B22C

Abstract:
1. A method of fabricating a core for a mold, comprising the following steps: (a) forming a porous core body according to selected dimensions from a composition comprising a binder and at least about 50% by weight of at least one rare earth metal oxide, based on the total weight of the core body; (b) heating the core body under heating conditions sufficient to remove a substantial portion of the binder and provide the core with a density of about 35% to about 80% of its theoretical density; (c) infiltrating the core body with a liquid colloid or solution which comprises particles of at least one metal oxide compound or precursor thereof, selected from the group consisting of rare earth metal oxides; silica, alumina, transition metal oxides, and combinations thereof; and then (d) heat-treating the particle-infiltrated core body under heating conditions sufficient to sinter the particles without substantially changing the dimensions of the core body.