Properties of an Infrared‐Transparent MgO:Y₂O₃ Nanocomposite

Abstract

A 50:50 vol% MgO-Y 2 O 3 nanocomposite with~150 nm grain size was prepared in an attempt to make 3-5 lm infraredtransmitting windows with increased durability and thermal shock resistance. Flexure strength of the composite at 21°C is 679 MPa for 0.88 cm 2 under load. Hardness is consistent with that of the constituents with similar grain size. For 3-mm-thick material at 4.85 lm, the total scatter loss is 1.5%, forward scatter is 0.2%, and absorptance is 1.8%. Optical scatter below 2 lm is 100%. Variable intensity OH absorption (~6% absorptance) is observed near 3 lm. The refractive index is 0.4% below the volume-fraction-weighted average of those of the constituents. Thermal expansion is equal to the volumefraction-weighted average of expansion of the constituents. Specific heat capacity is equal to the mass-fraction-weighted average of heat capacities of the constituents. Thermal conductivity lies between those of the constituents up to 1200 K. Elastic constants lie between those of the constituents. The Hasselman mild thermal shock resistance parameter for the composite is twice as great as that of common 3-5 lm window materials, but half as great as that of c-plane sapphire.

Effect of volume-fraction dependent agglomeration of nanoparticles on the thermal conductivity of nanocomposites: Applications to epoxy resins, filled by SiO2, AlN and MgO nanoparticles

“…The material properties of these components are given in Table 1 [34] b Calculated from Λ = 3 / by considering = 0.168 Wm -1 K -1 from Reference [20] c Reference [35] d Reference [36] e Calculated from Λ = 3 / by considering = 319 Wm -1 K -1 from Reference [36] f Calculated from experimental correlation given in Reference [37] g Calculated from = 3 / Λ by considering = 37 Wm -1 K -1 from Reference [38] h Interpolation from data at pages 625 and 626 from Reference [38] Note that the values in Table 1 have been obtained in the framework of the so-called "dispersion model" [39] where it is admitted that the phonons have different energies and 13 velocities due to their dispersion. In a previous work [40], we have studied the SiO2-epoxy mixture in absence of agglomeration, i.e.…”

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

“…Weibull parameters m = 23.32 and characteristic strength Sc = 1888 MPa. The calculation formula and principle refer to reference [11,30,31,32]. The strength is much higher than those of common infrared materials [33,34,35,36].…”

“…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.…”

Infrared-transparent glass ceramics: An exploratory study

“…The approach in the current work is to choose a composition region with two solid phases, make a glass with this composition, and then heat-treat it to form the two crystalline phases. This is a similar approach to that taken for the MWIR nanocomposite optical ceramic system of Y 2 O 3 -MgO [45]. The two targeted crystalline phases of Ge-La-S, assumed to be very similar in refractive index, were La 2 GeS 5 and La 4 Ge 3 S 12 .…”