High-temperature strengthening manufacturing of alumina-based ceramic molds used for hollow turbine blades

To solve the problem that alumina-based ceramic molds usually perform badly at high temperature, different kinds of impregnating materials have been compared. Results show that molds without strengthening perform badly with the strength less than 0.5 MPa (1500°C) and 10 MPa (20°C), while molds with strengthening perform differently. Molds impregnated with YCl₃ or MgCl₂ solution are not ideal, and there is a big expansion in the molds impregnated with MgCl₂ solution, which do not meet the application requirements. While by impregnating with silica solution or ethyl silicate hydrolyzate, the mechanical property of ceramic molds can be improved significantly. After impregnating with silica solution, the high-temperature strength is improved to 10 MPa (1500°C), meeting the demand of fabricating blades during unidirectional solidification. Shrinkage of the molds is restrained by compound impregnating, and at last a hollow turbine blade is successfully fabricated by casting.