| 초록 |
Infrared transparent materials have been studied for applying in next generation infrared-guided missiles, infrared radiation thermometer and missile domes. Accordingly, the infrared transparent ceramics should meet superior mechanical, chemical, optical and thermal properties for using the severe external environment. Transparent Y2O3 is one of the representative transparent and laser ceramics due to high transmittance in wide wavelength region. However, it is not suitable for application in harsh environment because of the insufficient mechanical properties. To improve the Y2O3 properties, Y2O3-MgO nanocomposite material has been studied for enhanced infrared transparent ceramics. As the amount of MgO increased, Y2O3 grain size decreases by Zener-pinning effect which resulted in improved mechanical properties as well as high transmittance in mid-IR region. Instead of the loss of the transmission in visible and ultraviolet by grain boundary scattering resulted from the large difference of refractive index. In this study, Y2O3-MgO nanoparticles were synthesized by glycine nitrate process under the various conditions and sintered by hot-pressing to minimize the unintended grain growth at the high temperature improving the optical and mechanical properties. By changing the synthesis and sintering condition, near-theoretical infrared transmittance and hardness could be obtained. |
