Polycrystalline and amorphous mullite fibers are employed as reinforcing phases in preparation of silicabased ceramic cores

respectively

and the effects of mullite fiber types on property of ceramic cores are investigated. Amorphous fibers are not so obvious as polycrystalline fibers in promoting crystallization of cristobalite

reducing shrinkage

and increasing porosity. Compared to polycrystalline fibers

the amorphous fibers have disordering structure similar to silica glass

they are easy to form tight binding with the matrix

enhancing the strength and creep resistance of ceramic cores. Moreover

the metastable structure of amorphous fibers ensures the high chemical activity in alkaline solutions

and the ceramic core exhibits excellent leaching rate. The silica-based ceramic core with a mass fraction of 3% amorphous mullite fibers exhibits excellent comprehensive performance

with bending strength of 27.7 MPa at room temperature and 22.4 MPa at high temperature

high temperature creep deformation of 0.31 mm

and leaching rate of 1.26 g/min

which can well meet the casting requirements of hollow blades.