Preparation of a ceramic core with high strength using an inorganic precursor and the gel-casting method

• The gel-casting method was used to fabricate the core with reasonable formability.
• The glassification efficiency of the inorganic binder affected the strength.
• Glass phases were homogeneously formed on the surfaces of starting particles.
• The prepared core was completely dissolved in a NaOH solution.

A new process for the preparation of a ceramic core with high formability and fracture strength is proposed. It involves the use of powders coated with inorganic binders, and gel-casting. Two types of powders were used to investigate the effect of the starting material on the mechanical properties (the green and sintering strength values) of the ceramic core, according to the components and particle sizes. Both the green and sintering strengths of the core samples prepared in Case II exhibited reasonable values, due to the long gelation time and the effective glassification of the inorganic precursor, respectively; a strength of about 10 MPa was achieved after 1 h heat treatment at 1000 °C. Furthermore, the prepared core samples completely dissolved in 40 wt.% NaOH solution. Specific experimental conditions were optimized for the application of precision casting, for example, the composition ratio (of the starting powders), the inorganic precursor, and the gel-casting method.