Transparent Polycrystalline Alumina Ceramics with Orientated Optical Axes

Abstract

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.

Sintering of α-alumina for highly transparent ceramic applications

“…While other compounds like spinel, 10 ) and, finally, some tried to orientate grains. 19 As a comparison, we show our results during the last two years on the same graph (Fig. 1).…”

Sintering to Transparency of Polycrystalline Ceramic Materials

“…All RIT values shown so far have been calculated considering texture less materials. However, different routes have shown the possibility to induce some texture in the polycrystalline materials (Salem et al, 1989;Mao et al, 2008;Uchikoshi et al, 2004). Figure 4.7b shows how at two wavelengths, 400 and 700 nm, the RIT increases with increasing texture.…”

Luminescent Zeolites

“…Actually, even for the paramagnetic materials, Al 2 O 3 , or Ca 5 (PO 4 ) 3 F, for instance, under such strong magnetic field, aligning grains along the c-axis can be also be achieved [13,14]. Efforts may be deserved on providing other novel structures or architectures or decorating methods which can reduce the applied magnetic field to facilitate the orientation alignment with moderate magnetic field.…”