Synthesis of MgO Coating Gd2O3 Nanopowders for Consolidating Gd2O3-MgO Nanocomposite with Homogenous Phase Domain Distribution and High Mid-Infrared Transparency

Abstract

Improved optical and mechanical properties are required for future infrared windows working in harsher mechanical and thermal environments than today. Ameliorating the homogeneity of the phase domain and reducing the size of the phase domain are effective approaches for enhancing the optical transmittance and mechanical hardness of a nanocomposite. In this work, we reported that the Gd2O3-MgO nanopowders were prepared by two different processes. The core–shell nanopowders synthesized by urea precipitation have a much lower agglomeration than the nanopowders prepared by sol–gel. Excellent transmittance (70.0%–84.1%) at 3–6 μm mid-infrared wave range and a high Vickers hardness value (10.3 ± 0.6 GPa) were maintained using the nanopowders synthesized by urea precipitation mainly due to its homogenous phase domain distribution.

Erbium-Doped Lu2O3-MgO and Sc2O3-MgO IR-Transparent Composite Ceramics

“…Typically, laser ceramics are single-phase and have a cubic crystal lattice to avoid passive optical losses due to scattering [ 3 ]. Recently, it has been shown that it is possible to obtain two-phase Y 2 O 3 -MgO [ 4 , 5 , 6 , 7 ] and Gd 2 O 3 -MgO [ 8 , 9 , 10 ] ceramics with transmission in the wavelength range of 1.5–8 μm at the level of single crystals of rare earth sesquioxides by reducing the grain size to at least a tenth of a wavelength, e.g., 100–200 nm. Such nanocomposites have advantages over sesquioxides in both mechanical properties and thermal conductivity [ 11 , 12 ].…”

Ceramic Films and Coatings: Properties and Applications

“…Improving the phase domain uniformity and reducing the phase domain size are effective ways to increase the transmittance and mechanical hardness of nanocomposites. The Gd 2 O 3 -MgO nano-powders produced via the urea precipitation method have good transmittance and high Vickers hardness in the mid-infrared band of 3-6 µm, mainly attributed to the uniform distribution of phase domains [18]. Moreover, the Special Issue includes two papers discussing microwave absorbing materials.…”