Ceramic composite materials, articles, and methods

Patent metadata

Field	Value
Publication number	US-11066333-B2
Application number	US-201916279684-A
Country	US
Kind code	B2
Filing date	Feb 19, 2019
Priority date	Feb 19, 2018
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

Methods of forming composite materials, composite materials, and articles. The composite materials may include electromagnetic shielding materials. The methods may include providing a mixture of ultra-high temperature ceramic particles and a liquid preceramic precursor, curing the mixture to form a solid mixture, forming particles of the solid mixture, and pressing the particles into a mold.

First claim

The invention claimed is:

1. A method of forming a composite material, the method comprising:
providing a mixture comprising (i) ultra-high temperature ceramic particles and (ii) a liquid preceramic precursor;
heating the mixture at a temperature for a time effective to cure the liquid preceramic precursor to form a solid mixture;
subjecting the solid mixture to one or more forces to form particles of the solid mixture; and
pressing the particles of the solid mixture into a mold having a pre-selected shape to form the composite material.

2. The method of claim 1 , further comprising sintering the composite material.

3. The method of claim 1 , wherein each of the particles of the solid mixture comprises (a) a core region comprising an amount of the ultra-high temperature ceramic particles, and (b) a surface region comprising an amount of the cured liquid preceramic precursor; and for each of the particles (i) the amount of the ultra-high temperature ceramic particles of the core region includes at least 75%, by weight, of the ultra-high temperature ceramic particles that are present in each particle, and (ii) the amount of the cured liquid preceramic precursor of the surface region includes at least 75%, by weight, of the cured ceramic precursor that is present in each particle.

4. The method of claim 1 , wherein the subjecting of the solid mixture to one or more forces comprises compressing the solid mixture, grinding the solid mixture, or a combination thereof.

5. The method of claim 4 , wherein the grinding of the solid mixture comprises ball milling the solid mixture.

6. The method of claim 1 , wherein the ultra-high temperature ceramic particles have a melting temperature of at least 2,000° C.

7. The method of claim 6 , wherein the ultra-high temperature ceramic particles have at least one of the following properties: [1] an elastic modulus of at least 500 GPa, [2] a hardness of at least 20 GPa, [3] an electrical conductivity of at least 10 7 S/m, or [4] a thermal conductivity of about 60 to about 120 W/m*K.

8. The method of claim 1 , wherein the ultra-high temperature ceramic particles are selected from the group consisting of a boride, a carbide, and a nitride.

9. The method of claim 1 , wherein the ultra-high temperature ceramic particles comprise HfB 2 , ZrB 2 , TiB 2 , NbB 2 , TaB 2 , or a combination thereof.

10. The method of claim 1 , wherein the ultra-high temperature ceramic particles comprise TaC, HfC, ZrC, NbC, TiC, or a combination thereof.

11. The method of claim 1 , wherein the ultra-high temperature ceramic particles comprise TaN, HfN, TiN, ZrN, NbN, or a combination thereof.

12. The method of claim 1 , wherein the liquid preceramic precursor comprises an organosilicon polymer.

13. The method of claim 12 , wherein the organosilicon polymer comprises polycarbosilane.

14. A method of forming a composite material, the method comprising:
providing a mixture comprising (i) ultra-high temperature ceramic particles and (ii) a liquid preceramic precursor, wherein the ultra-high temperature ceramic particles comprise a nitride, a boride, a carbide, or a combination thereof having a melting temperature of at least 2,000° C.;
heating the mixture at a temperature for a time effective to cure the liquid preceramic precursor to form a solid mixture;
subjecting the solid mixture to one or more forces to form particles of the solid mixture, wherein each of the particles of the solid mixture comprises (a) a core region comprising an amount of the ultra-high temperature ceramic particles, and (b) a surface region comprising an amount of the cured liquid preceramic precursor; and for each of the particles (i) the amount of the ultra-high temperature ceramic particles of the core region includes at least 75%, by weight, of the ultra-high temperature ceramic particles that are present in each particle, and (ii) the amount of the cured liquid preceramic precursor of the surface region includes at least 75%, by weight, of the cured ceramic precursor that is present in each particle;
pressing the particles of the solid mixture into a mold having a pre-selected shape to form the composite material; and
sintering the composite material.

15. The method of claim 14 , wherein the liquid preceramic precursor comprises an organosilicon polymer.

Assignees

• Univ Florida State Res Found Inc

Inventors

• Xu Cheryl

Classifications

• C04B2235/3839

  Refractory metal carbides · CPC title

• C04B35/645

  Pressure sintering · CPC title

• B64D45/02

  Lightning protectors; Static dischargers · CPC title

• C04B35/62834 Primary

  Silicon carbide · CPC title

• C04B2235/3813

  Refractory metal borides · CPC title