Micro-porous ceramics using directionally solidified MgAl2O4/MgO eutectic crystals

Novel process was tried to obtain micro-porous ceramic body containing continuous pore channel. MgAl2O4/MgO eutectic fibers and rods have been grown successfully by the micro-pulling-down method, and the microstructures and optical characterizations of grown crystals were performed. MgAl2O4/MgO eutectic fibers of 0.3-1 mm in diameter and about 500 mm in length, and the rods having 5 mm in diameter with approximately 60 mm in length have been grown with the 6-120 mm/hr of growth speed. The eutectic fibers showed homogeneous microstructure in which MgO fiber aligned to the growth direction in the MgAl2O4 (spinel) matrix. The grown crystals looked semitransparency under naked eyes. Optical and orientational characterizations were performed. The second phase of MgO (periclase) was easily removed by selective etching with hydrochloric acid, and then porous bodies were obtained.