Y₂O₃–MgO–ZrO₂ Infrared Transparent Ceramic Nanocomposites

Abstract

Increased strength and improved erosion resistance are required for future infrared windows working in harsher mechanical and thermal environments than those used today. In this study, Y2O3–MgO–ZrO2 composite nanopowders were synthesized using a sol–gel combustion process. The fully dense Y2O3–MgO–ZrO2 nanocomposites were prepared by pressureless sintering of the nanopowders at 1400°C for 2 h, followed by hot isostatic pressing at 1350°C for 1 h. The effects of ZrO2 concentration on the microstructure, infrared transmittance, and microhardness of the nanocomposites were studied. It is shown by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) that ZrO2 is selectively soluble in Y2O3 with the concentration up to 13.2 mol%, forming supersaturated solid solution. The microhardness of the Y2O3–MgO–ZrO2 nanocomposites scales linearly with the square root of the ZrO2 concentration (from 10.6 GPa without ZrO2 to 13.5 GPa with 13.2 mol% ZrO2 addition). Good mid‐infrared transmittance (53%–70%) over 3–7 μm wavelength was maintained with ZrO2 concentration up to 8.8 mol%, compared with that of Y2O3–MgO nanocomposites (62%–80%) at the same wavelength range. This work shows ZrO2 solid solution strengthened Y2O3 (ZSSY) nanocomposites for their potential to be used as infrared transparent materials with enhanced mechanical properties.

Preparation and Optical Properties of Infrared Transparent 3Y-TZP Ceramics

“…Y 2 O 3 –MgO nanocomposite was recently reported to have excellent mid-infrared transmittance over three- to seven-micrometer wavelength ranges with improved mechanical properties over that of pure yttria and magnesia polycrystalline dense ceramics [10,11,12,13]. However, harsher mechanical and thermal environments have imposed more stringent requirements for improved mechanical strength and optical properties of infrared transparent windows and domes.…”

High Reactive MgO‐Y2O3 Nanopowders via Microwave Combustion Method and Sintering Behavior

“…Many approaches such as sol‐gel, combustion, and flame pyrolysis techniques have been employed to synthesize MgO‐Y 2 O 3 nanopowders . Among these methods, the combustion method has become the most efficient choice in case of large‐scale economical production of nanopowders.…”

Hot Pressing of Infrared‐Transparent Y2O3–MgO Nanocomposites Using Sol–Gel Combustion Synthesized Powders

“…And the transmittance can be significantly increased when the grain size is substantially smaller than the incident light wavelength. In general, the reduced grain size will increase the optical transparency of the nanocomposite ceramics by reducing the light scattering at grain boundaries . In addition, according to the Petch equation, the mechanical strength decreases with the increase of grain size, so the reduced grain size will also improve the mechanical strength of the composite nanoceramic, and the increased mechanical strength will further increase the thermal shock resistance.…”

“…In general, the reduced grain size will increase the optical transparency of the nanocomposite ceramics by reducing the light scattering at grain boundaries. [6][7][8] In addition, according to the Petch equation, the mechanical strength decreases with the increase of grain size, so the reduced grain size will also improve the mechanical strength of the composite nanoceramic, and the increased mechanical strength will further increase the thermal shock resistance. It has been reported that the Y 2 O 3 -MgO nanocomposite ceramic is transparent in the mid-IR wavelength range, and the thermal shock resistance of Y 2 O 3 -MgO nanocomposite ceramic is higher than most of other mid-infrared window materials.…”