Y2O3–MgO composites are optical materials with promising applications for mid-infrared windows in extreme environments. Considering the refractive index differences between different phases and the Hall–Petch effect, intensifying phase homogeneity and reducing grain size enhances the optical and mechanical properties of composites. The grain sizes of composites are also influenced by phase homogeneity. However, research on the relationship and mechanism of phase homogeneity with the optical and mechanical properties of Y2O3–MgO composites is not quantitative and lacks gradient data support. In this study, the phase homogeneity was quantified and utilized as a gradient parameter to fabricate Y2O3–MgO composites by regulating the solvothermal temperature during powder synthesis. As the phase homogeneity increases, scattering is reduced and the grain size decreases, resulting in improved properties (transmittance at ∼6 μm rises from ∼5.5% to ∼81.5%). The gradientization and quantitative analysis of phase homogeneity in Y2O3–MgO composites can serve as a reference on optical composites, aiding in the optimization of properties.
Xincheng Cai,Junjing Duan,Zhangyi Huang,Zhenyu Zhang,Shengquan Yu,Xiaoqiang Li,Jianqi Qi,Tiecheng Lu
Y 2 O 3 -MgO composites are promising for mid-infrared windows and domes in harsh environments. However, the insufficient transmittance range (the transmittance >30 % only in ∼2–7 μm) and strong absorption peak (the transmittance <32 % at 7.0 μm) of Y 2 O 3 -MgO composites severely limit their application range because of agglomerations and carbon contamination from organics in the raw materials, currently. In this study, utilizing carbon-free raw materials and high molecular motions, the reduction of carbon contamination and agglomerations within the as-synthesized nanopowers was achieved via the modified co-precipitation synthesis. A highly mid-infrared transparent (the maximum transmittance of 79 % at 6.0 μm) Y 2 O 3 -MgO composite with wide transmittance range (the transmittance >30 % in 2.2–9.7 μm) and weak absorption peaks (the transmittance ≈68.57 % at 7.0 μm) was fabricated by the hot-pressing sintering method using the as-obtained nanopowders in the absence of exogenous dopants. And the modified co-precipitation synthesis is a method with great potential for the development of mid-infrared transparent Y 2 O 3 -MgO composites with wide transmittance range and weak absorption peaks.
Xincheng Cai,Junjing Duan,Zhangyi Huang,Lexing Liang,Zhenyu Zhang,Mao Deng,Jianqi Qi,Tiecheng Lu
Y 2 O 3 MgO composites have emerged as promising mid-infrared (MIR) materials owing to their exceptional broadband transmittance and remarkable thermal stability at elevated temperatures. Nevertheless, the presence of uncontrollable absorption bands within the 4–7 μm spectral range, compromises their optical performance in advanced MIR systems. To address this limitation, we systematically investigated annealing as a strategic approach for modulating defect chemistry in oxide composites. In this paper, the absorption peaks of Y 2 O 3 MgO composites were controlled by varying the annealing conditions. As the annealing temperature increases from 600 °C to 1100 °C, the absorption peaks of Y 2 O 3 MgO composites gradually shift from ∼4.9 μm to ∼6.8 μm, with a transition temperature ∼900°C. This behavior is attributed to the oxidation of metal-organic coordination (MOC) to CO 3 2- in high-temperature air. Ultimately, Y 2 O 3 MgO composites featuring controllable absorption peaks were obtained, demonstrating a transmittance of ∼81 % at 7 μm - the highest value ever reported for this composite system, which broadens the potential application space, particularly in fields requiring mid-infrared transparency such as gas detection, materials characterization, and biomedical imaging. This study not only elucidates specific strategies for enhancing the performance and microstructure of Y 2 O 3 MgO composites but also furnishes reliable methodologies and datasets to support the annealing processes of other material systems.
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