|About this Abstract
||Materials Science & Technology 2019
||Ceramic and Crystal Materials for Optics and Photonics
||Transparent MgAl2O4 Spinel Ceramics with Enhanced Strength via Suppressing the Grain Growth
||Ha-Neul Kim, Ji-Won Kim, Jae-Woong Ko, Young-Jo Park, Jon-Do Yun, Young-Chul Kim, Ki-Deok Yang
|On-Site Speaker (Planned)
Transparent magnesium aluminate (MgAl2O4) having the high strength over 300MPa, was developed via suppressing grain growth. Two technical approaches have been applied; One is to induce the grain boundary pinning through the Ca segregation, and the other is the hot-isostatic press followed by hot press at low temperature.
The light transmittance and the flexural strength were significantly different depending on the route of Ca addition. When Ca(NO3)2 salt was added to the spinel slurry, an excellent strength of 312MPa as well as a high light transmittance of 73.5% at 400nm wavelength(thickness=3.5mm) were achieved for the spinel with suppressed grain size of 324nm.
A novel process, combining hot-press and hot-isostatic press without sintering additive, was very successful to enhance the flexural strength of transparent MgAl2O4. We have achieved the highest flexural stength of 335MPa and an admirable light transmittance of 78.1% at 400nm (thickness=4.0mm) for the 150×150mm tile-shaped MgAl2O4.