Refractory metal boride ceramics and methods of making thereof
A composition having nanoparticles of a refractory-metal boride and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising a metal component, boron, and an organic component. The metal component is nanoparticles or particles of a refractory metal or a refractory-metal compound capable of decomposing into refractory metal nanoparticles. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining particles of a refractory metal or a refractory-metal compound capable of reacting or decomposing into refractory-metal nanoparticles, boron, and an organic compound having a char yield of at least 60% by weight to form a precursor mixture. A composition having nanoparticles of a refractory-metal boride that is not in the form of a powder.
1. A composition comprising:
nanoparticles of a refractory-metal boride; and
a carbonaceous matrix;
wherein the composition is not in the form of a powder and is oxidatively stable at 3000° C.
2. The composition of claim 1 , wherein the nanoparticles comprise titanium boride.
3. The composition of claim 1 , wherein the nanoparticles comprise zirconium boride, hafnium boride, tungsten boride, or tantalum boride.
4. The composition of claim 1 , wherein the refractory metal is a group IV-VI transition metal, niobium, molybdenum, chromium, or vanadium.
5. The composition of claim 1 , wherein the composition comprises at least 5% by weight of the nanoparticles.
6. The composition of claim 1 , wherein the composition comprises at least 99% by weight of the nanoparticles.
7. The composition of claim 1 , wherein the average diameter of the nanoparticles is less than 100 nm.
8. The composition of claim 1 , wherein the carbonaceous matrix comprises graphitic carbon, carbon nanotubes, or amorphous carbon.
9. The composition of claim 1 , wherein the composition further comprises:
nanoparticles comprising a carbide or nitride of the refractory metal.
10. The composition of claim 1 , wherein the composition further comprises:
fibers, carbon fibers, ceramic fibers, or metal fibers.
11. The composition of claim 1 , wherein the composition contains less than 20% by volume of voids.
12. An article comprising the composition of claim 1 , wherein the article is in the form of a solid, unbroken mass having a minimum size of at least 1 mm in all dimensions.
13. The article of claim 12 , wherein the surface of the article comprises an oxide of the refractory metal.
14. A composition comprising:
nanoparticles of a refractory-metal boride;
wherein the composition is not in the form of a powder; and
wherein the composition comprises at least 99% by weight of the nanoparticles.
15. The composition of claim 14 , wherein the nanoparticles comprise zirconium boride.
16. The composition of claim 14 , wherein the refractory metal is a group IV-VI transition metal, titanium, hafnium, tungsten, tantalum, niobium, molybdenum, chromium, or vanadium.
17. An article comprising the composition of claim 14 , wherein the article is in the form of a solid, unbroken mass having a minimum size of at least 1 mm in all dimensions.