Infrared‐Transparent Y₂O₃–MgO Nanocomposites Using Sol–Gel Combustion Synthesized Powder

Abstract

Y2O3–MgO composite nanopowder with a volume ratio of 50:50 was synthesized using a sol–gel combustion process. X‐ray diffraction analysis of the as‐synthesized nanopowder shows phase pure Y2O3 and MgO with a cubic crystal structure and crystalline size ∼15 nm. The fully dense Y2O3–MgO nanocomposites were prepared by pressureless sintering the composite nanopowder at 1400°C for 2 h, followed by hot isostatic pressing at 1350°C for 1 h and postsinter annealing at 1000°C for 10 h. The Y2O3–MgO nanocomposite exhibit excellent infrared transmittance (62%–80%) over 3–7 μm infrared wavelength ranges with an average hardness of 10.6 GPa.

Properties of an Infrared‐Transparent MgO:Y2O3 Nanocomposite

“…Wang et al . reported a hardness of 10.6 ± 0.4 GPa for M:Y made from sol‐gel power . Stefanik et al .…”

“…Optical, mechanical, and thermal properties of 50:50 vol% MgO:Y 2 O 3 nanocomposite (abbreviated M:Y) are compared with those of MgO and Y 2 O 3 . Two reports on M:Y prepared by alternate means have appeared …”

Y2O3–MgO–ZrO2 Infrared Transparent Ceramic Nanocomposites

“…The Y 2 O 3 –MgO nanopowder synthesized after combustion has an average crystallite size of ~15 nm and a specific surface area of 35.2 m 2 /g. The details of the nanopowder fabrication procedures and characterizations can be found in our previous report . In this study, the addition of 4.4, 8.8 and 13.2 mol% ZrO 2 in Y 2 O 3 –MgO nanopowder was achieved by adding different concentration of zirconia acetate solution (C 8 H 16 O 8 Zr, 99.9+%, equivalent 22 wt% ZrO 2 ; Inframat, Manchester, CT).…”

“…In addition, increased strength and improved erosion resistance can also be achieved . Y 2 O 3 –MgO nanocomposite was recently reported to have excellent mid‐infrared transmittance over 3–7 μm wavelength ranges with improved mechanical properties over that of pure yttria and magnesia polycrystalline dense ceramics . In order to protect infrared windows from harsher mechanical and thermal environments and to replace currently used single crystal materials, such as sapphire, a further improvement of the mechanical properties of the ceramic nanocomposites is required.…”

A Sucrose‐Mediated Sol–Gel Technique for the Synthesis of MgO–Y2O3 Nanocomposites

“…Ceramics intended for use in infrared (IR) transparent windows need to meet certain criteria that include optical transparency, high mechanical strength, high thermal conductivity, and resistance to thermal shock and erosion . Yttria (Y 2 O 3 ) is an attractive ceramic for optical purposes due to its cubic structure yielding isotropic properties, longer cut‐off wavelength (up to 5 μm) than other optical materials (sapphire, ALON, and spinel), low emissivity, and low scatter . In ceramics like Y 2 O 3 , grain growth can be inhibited by the incorporation of other oxide phases, to give an oxide/oxide composite wherein each phase pins the grain boundaries of the other .…”