A novel MgAl2O4/MgO ceramic core with water-collapsibility

Ceramic cores are the critical components in the hollow turbine blade casting. Due to the rigorous requirements for both high temperature creep resistance and the removal performance, only a few material systems can be applied to this area. However, each of them also has disadvantages on either of the two conflicting requirements. In order to conquer this difficulty, a novel multi-phase MgAl2O4/MgO ceramic was fabricated by reaction sintering in this work. The obtained materials had the porous structure of MgAl2O4 embedded by MgO minor phase, and its creep resistance at 1550 degrees C was even better than alumina ceramics. More importantly, the removal of the multi-phase ceramic can be fulfilled via hydrothermal treatment in pure water. A new mechanism was revealed that the collapse was caused by the volume expansion during hydration of the MgO grain rather than the corrosion or dissolution. The MgO grain embedded in the porous structure served as a structure-shatter phase. This material has enormous potential in the application of ceramic core.