Al additions for grain pinning in Y2O3—MgO

Patent metadata

Field	Value
Publication number	US-12129209-B2
Application number	US-202217648921-A
Country	US
Kind code	B2
Filing date	Jan 25, 2022
Priority date	Feb 17, 2021
Publication date	Oct 29, 2024
Grant date	Oct 29, 2024

Abstract

A nanocomposite optical ceramic (NCOC) material. The material having a first solid phase, a second solid phase, and a third solid phase. The first solid phase has first solid phase grains no larger than 5 μm, and each first solid phase grain has a first solid phase grain boundary. The second solid phase has second solid phase grains no larger than 5 μm, and each second solid phase grain has a second solid phase grain boundary. The third solid phase has a doping agent. The doping agent is less than 5 atomic % soluble in the first solid phase and the second solid phase. At least part of the third solid phase is situated at the second solid phase grain boundary.

First claim

The invention claimed is:

1. A nanocomposite optical ceramic (NCOC) material comprising:
a first solid phase, consisting of first solid phase grains no larger than 5 μm, each first solid phase grain having a first solid phase grain boundary, wherein the first solid phase comprises magnesium oxide;
a second solid phase consisting of second solid phase grains no larger than 5 μm, each second solid phase grain having a second solid phase grain boundary, wherein the second solid phase comprises yttrium (III) oxide; and
a third solid phase comprising a doping agent, wherein the doping agent is less than 5 atomic % soluble in the first solid phase and the second solid phase, wherein the doping agent comprises aluminum, aluminum oxide, or some combination thereof;
wherein the doping agent combines with the first solid phase or the second solid phase to form a pinning phase that is interspersed between grains of the first solid phase and the second solid phase such that a three-phase system of MgO, Y 2 O 3 and Y 4 Al 2 O 9 is formed, wherein the three-phase system has a ratio of Y 4 Al 2 O 9 :Y 2 O 3 +MgO of between 1:200 and 1:3.

2. The NCOC of claim 1 wherein the size of the first solid phase grain is less than 1 μm.

3. The NCOC of claim 1 wherein the size of the first solid phase grain is less than 0.5 μm.

4. The NCOC of claim 1 wherein the doping agent is no more than 5 volume % of the NCOC.

5. The NCOC of claim 1 wherein the first solid phase grains grow no more than 20% after being subjected to 1400° ° C. for 1 hour.

6. The NCOC of claim 1 wherein the NCOC has a transmission of at least 80% at a wavelength of 3 μm wherein the NCOC is 2 mm thick.

Assignees

• Raytheon Co

Inventors

• Smith Kenneth
• Bell Stephanie Silberstein
• Nordahl Christopher S
• Hartnett Thomas M
• Gentilman Richard
• Jackson R Wesley

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C04B2235/785

  Submicron sized grains, i.e. from 0,1 to 1 micron · CPC title

• C04B2235/402

  Aluminium · CPC title

• C04B2235/3217

  Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina · CPC title

• C04B2235/85

  Intergranular or grain boundary phases · CPC title