Process for improving flash sintering of ceramics and improved ceramics

Patent metadata

Field	Value
Publication number	US-12319623-B2
Application number	US-202017434719-A
Country	US
Kind code	B2
Filing date	Feb 27, 2020
Priority date	Feb 27, 2019
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

Methods of flash sintering have been developed in which particle are initially coated with thin layers by atomic layer deposition (ALD). Examples are provided in which 8 mol % yttria-stabilized zirconia (8YSZ) particles are coated with small quantities of Al 2 O 3 by particle atomic layer deposition (ALD). Sintered materials that result from the process have been characterized. Sintered materials having unique characteristics are also described.

First claim

What is claimed:

1. A method of flash sintering, comprising:
providing particles comprising a first phase of boron carbide and having a surface;
using ALD to grow a film of a second phase on the surface of the particles to form a coated powder composition; and
flash sintering the coated powder composition.

2. The method of claim 1 wherein the ALD coating on the coated powder composition is semi-continuous and covers 90% or less of the surface area of the particles.

3. The method of claim 1 comprising, prior to the step of flash sintering, mixing the coated powder with a binder, forming a shaped component, and heating the shaped component to burn out the binder.

4. The method of claim 1 wherein ALD is used to grow an alumina film.

5. The method of claim 1 comprising one to five cycles or one to eight cycles of ALD.

6. The method of claim 5 wherein the alumina film has a thickness of between about 0.5 nm and about 1 nm.

7. The method of claim 1 comprising at least 9 cycles of ALD.

8. The method of claim 1 wherein the second phase increases the temperature at which flash sintering occurs, relative to the first phase.

9. The method of claim 1 wherein the second phase decreases the temperature at which flash sintering occurs, relative to the first phase.

10. The method of claim 1 wherein the ALD coating on the coated powder composition is semi-continuous and covers 70% or less of the surface area of the particles.

11. The method of claim 1 wherein the ALD coating on the coated powder composition is semi-continuous and covers 50% or less of the surface area of the particles.

12. The method of claim 1 wherein the second phase comprises Al 2 O 3 , Y 2 O 3 , MgO, or V 2 O 5 .

13. The method of claim 1 wherein the flash sintering is performed at atmospheric pressure.

14. The method of claim 1 wherein the ALD includes providing a linker agent.

15. The method of claim 1 wherein the ALD includes providing a terminating agent.

16. The method of claim 1 wherein the film comprises titanium oxide.

17. The method of claim 1 wherein the film comprises titanium diboride.

18. The method of claim 1 wherein the particles have a diameter in the range of 100 micrometers to 500 micrometers.

19. The method of claim 1 wherein the film comprises an oxide, a nitride, a sulfide, a phosphide, a metal fluoride, a transition metal oxyfluoride, a transition metal oxynitride, a lanthanide, a boride, or a silicon-containing material.

20. The method of claim 1 wherein the film comprises Al 2 O 3 , TiO 2 , ZnO, ZrO 2 , SiO 2 , HfO 2 , Ta 2 O 5 , LiNb x O y , TiN, TaN, W 2 N, TiY 2 N, ZnS, CdS, SnS, WS 2 , MoS 2 , ZnIn 2 S 4 , GaP, InP, Fe 0.5 Co 0.5 P AlF 3 , MgF 2 , ZnF 2 , transition metal oxyfluorides or oxynitrides, a lanthanide, a boride, a carbide, or a silicon containing material.

Assignees

• Univ Colorado Regents

Inventors

• Weimer Alan
• Yoon Bola
• Raj Rishi
• O'Toole Rebecca

Classifications

• H01M2300/0094

  in the form of layered products, e.g. coatings · CPC title

• H01M2300/0077

  based on zirconium oxide · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M8/1253

  the electrolyte containing zirconium oxide · CPC title

• C23C16/56

  After-treatment · CPC title