Transparent Polycrystalline Alumina Ceramics with Orientated Optical Axes

A novel method is reported for the manufacture of transparent polycrystalline alumina ceramics by means of orientating the optical axes of grains parallel to each other. Such ceramics were achieved simply by exposing the slip casting process to a strong magnetic field followed by the traditional processing for translucent alumina ceramics. X-ray diffraction and orthogonal polarizing microscopy showed that the grains have been successfully orientated in the alumina ceramics. The in-line optical transmission is much higher than that of the randomly orientated polycrystalline alumina because the optical axes of grains are parallel to each other.