Product made from silicon carbide for shielding

Patent metadata

Field	Value
Publication number	US-9321691-B2
Application number	US-201314408181-A
Country	US
Kind code	B2
Filing date	May 17, 2013
Priority date	Jun 15, 2012
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A product obtained by solid-phase sintering of a silicon carbide powder and of a sintering additive, the product having a relative density of greater than 98.5% and including: more than 92% by weight of SiC present in the form of grains, less than 2% by weight of elemental oxygen, less than 6% by weight, in total, of other elements, wherein more than 10% by number of the SiC grains, on the basis of the total number of the grains, have an elongation factor F of greater than 3 (F>3), wherein more than 50% by number of the grains, the elongation factor F of which is greater than 3, have a width of greater than 3 micrometers, and wherein the other SiC grains in the product have a mean equivalent diameter of greater than 1 micrometer and less than 20 micrometers.

First claim

The invention claimed is:

1. A product obtained by solid-phase sintering of a silicon carbide powder and of a sintering additive, said product having a relative density of greater than 98.5% and comprising:
more than 92% by weight of SiC present in the form of grains,
less than 2% by weight of elemental oxygen, and
less than 6% by weight, in total, of other elements,

wherein:
more than 10% by number of the SiC grains, on the basis of a total number of said SiC grains, have an elongation factor greater than 3,
more than 50% by number of said SiC grains, the elongation factor of which is greater than 3, have a width of greater than 3 micrometers, and
a remaining number of SiC grains, of the total number of said SiC grains, in said product have a mean equivalent diameter greater than 1 micrometer and less than 20 micrometers and the number of SiC grains having an elongation factor greater than 6 is less than 7%, and
wherein the product has an aluminum content that is less than 1000 ppm relative to the weight of said product.

2. The product as claimed in claim 1 , comprising between 0.1% and 4% by weight of at least one other element chosen from boron, titanium, zirconium and free carbon and less than 2% by weight, in total, of other elements.

3. The product as claimed in claim 2 , wherein a sum, by weight, of the at least one other element chosen boron, free carbon, titanium and zirconium is between 0.2% and 3.2% by weight.

4. The product as claimed in claim 3 , wherein the sum, by weight, of the at least one other element chosen boron, free carbon, titanium and zirconium is less than 2% by weight.

5. The product as claimed in claim 1 , wherein the sintering additive is selected from carbon, carbides of boron, titanium and zirconium or borides of zirconium and titanium, alone or as a mixture.

6. The sintered product as claimed in claim 1 , comprising between 0.1% and 0.5% by weight of boron and between 0.1% and 2.7% by weight of free carbon.

7. The product as claimed in claim 6 , wherein the sintering additive comprises or consists of a mixture of boron carbide and carbon.

8. The sintered product as claimed in claim 1 , having a relative density of greater than 99%.

9. The sintered product as claimed in claim 1 , wherein a total sum of lanthanide elements, actinide elements and yttrium in the product is less than 0.05% by weight.

10. The sintered product as claimed in claim 1 , wherein the aluminum content is greater than 50 ppm, relative to the weight of said product.

11. The product as claimed in claim 1 , wherein the number of SiC grains having an elongation factor greater than 3 is greater than 15% and less than 40%.

12. The product as claimed in claim 1 , wherein more than 60% by number of SiC grains, having an elongation factor greater than 3, have a width greater than 3 micrometers.

13. The product as claimed in claim 1 , wherein the number of SiC grains having an elongation factor greater than 4 is greater than 2% and is less than 15%.

14. The product as claimed in claim 1 , wherein the number of SiC grains having an elongation factor greater than 5 is greater than 1% and is less than 8%.

15. The product as claimed in claim 1 , wherein the number of SiC grains having an elongation factor greater than 8 is less than 1%.

16. The product as claimed in claim 1 , wherein each grain having an elongation factor greater than 3 is in contact with at least one other grain having an elongation factor greater than 3.

17. The product as claimed in claim 1 , wherein more than 20% of the grains, having an elongation factor greater than 3, additionally have a width greater than 4 micrometers.

18. The product as claimed in claim 1 , wherein more than 15% by number of said other SiC grains in said product have an elongation factor greater than 2.

19. The product as claimed in claim 1 , wherein the other SiC grains in said product have a mean equivalent diameter of greater than 2 micrometers and less than 9 micrometers.

20. The product as claimed in claim 19 , wherein the other SiC grains in said product have a mean equivalent diameter greater than 4 micrometers.

21. The product as claimed in claim 1 , comprising no or substantially no intermediate zones between the SiC grains, the oxygen content of which is greater than 15% by weight and a greatest length of which is greater than or equal to 50 nm.

22. The product as claimed in claim 1 , wherein the total content of oxygen element is less than 1% by weight.

23. An armor or armor-plating component comprising, a sintered product as claimed in claim 1 .

24. The product as claimed in claim 11 , wherein the number of SiC grains having an elongation factor greater than 3 is greater than 18% and less than 35%.

25. The product as claimed in claim 16 , wherein each grain having an elongation factor greater than 3 is in contact with at least two other grains having an elongation factor greater than 3.

26. The product as claimed in claim 17 , wherein more than 30% of the grains having an elongation factor greater than 3 additionally have a width of greater than 4 micrometers.

27. The product as claimed in claim 18 , wherein more than 20% by number of said other SiC grains in said product have an elongation factor greater than 2.

28. The product as claimed in claim 20 , wherein the other SiC grains in said product have a mean equivalent diameter greater than 5 micrometers.

Assignees

• Saint Gobain Ct Recherches
• Centre Nat Rech Scient

Inventors

• Rossiquet Gilles
• Jorge Eric

Classifications

• C04B2235/3813

  Refractory metal borides · CPC title

• F41H5/0414 Primary

  Layered armour containing ceramic material · CPC title

• C04B2235/76

  Crystal structural characteristics, e.g. symmetry · CPC title

• C04B2235/6562

  Heating rate · CPC title

• C04B2235/788

  Aspect ratio of the grains · CPC title