Boron carbide sintered body and method of manufacturing the same and protective body
A boron carbide sintered body having a plurality of pores, comprises a boron carbide as a main component and a plurality of graphite particles dispersed in the sinter. The graphite particles is exposed to the pores or is in the vicinity of the pores.
1. A boron carbide sintered body having a plurality of pores, comprising:
a boron carbide as a main component,
a plurality of graphite particles dispersed in the sinter, a majority of the graphite particles being exposed to the pores.
2. The boron carbide sintered body according to claim 1 , further comprising a silicon carbide.
3. The boron carbide sintered body according to claim 1 , wherein the graphite particles have an anisotropic shape.
4. The boron carbide sintered body according to claim 1 , wherein a mean maximum length of the graphite particles is not less than 1 micron and not more than 15 microns.
5. The boron carbide sintered body according to claim 1 , having a porosity of not more than 10%.
6. The boron carbide sintered body according to claim 5 , wherein the porosity is not less than 1% and not more than 6%.
7. The boron carbide sintered body according to claim 1 , wherein the sintered body has a top surface, a bottom surface, and a side circumferential surface connecting a periphery of the top surface and a periphery of the bottom surface, and at least one of the top surface and the bottom surface is a convex surface.
8. The boron carbide sintered body according to claim 1 , wherein a ratio of the length of the circumference of the cross-section of a graphite particle exposed to a pore to the length of the circumference of the cross-section of said pore (Lp/La) is not less than 0.3.
9. The boron carbide sintered body according to claim 1 , wherein a number of the graphite particles exposed to the pores is not less than 80% of the sum of the number of all of the graphite particles which are exposed to the pores and are disposed within 40 microns of the circumference of a pore.
10. A method of manufacturing a boron carbide sintered body, comprising:
mixing a boron carbide, graphite, and a silicon carbide to obtain a basic material,
molding the basic material to obtain a compact,
firing the compact to dissolve the graphite in the compact at a first reference temperature, heating the compact up to a second reference temperature higher than the first reference temperature, and
cooling the compact to precipitate the dissolved graphite,
thereby obtaining a boron carbide sintered body having a plurality of pores and comprising a boron carbide as a main component and a plurality of graphite particles dispersed in the sinter, a majority of the graphite particles being exposed to the pores.
11. The method of manufacturing a boron carbide sintered body according to claim 10 , wherein the firing is a pressureless firing.
12. The method of manufacturing a boron carbide sintered body according to claim 10 , wherein the first reference temperature is not less than 2100° C. and not more than 2300° C., and the second reference temperature is not less than 2200° C. and not more than 2350° C.
13. A protective body, comprising: a plurality of the boron carbide sintered bodies according to claim 1 , and a substrate on which the sintered bodies are disposed.
14. A boron carbide sintered body having a plurality of pores, comprising:
a boron carbide as a main component,
a plurality of graphite particles dispersed in the sinter, a majority of the graphite particles being exposed to the pores, and
a silicon carbide,
wherein a content of the graphite particles is not less than 1% and not more than 20% by mass of the sintered body, and a content of the silicon carbide is not less than 0.1% and not more than 10% by mass of the sintered body.
15. The boron carbide sintered body according to claim 14 , wherein the graphite particles have an anisotropic shape wherein a mean maximum length of the graphite particles is not less than 1 micron and not more than 15 microns.
16. The boron carbide sintered body according to claim 14 , wherein the porosity is not less than 1% and not more than 6%.
17. A protective body, comprising: a plurality of the boron carbide sintered bodies according to claim 14 , and a substrate on which the sintered bodies are disposed.
18. The boron carbide sintered body according to claim 9 , wherein the graphite particles have an anisotropic shape wherein a mean maximum length of the graphite particles is not less than 1 micron and not more than 15 microns.
19. The boron carbide sintered body according to claim 9 , wherein the porosity is not less than 1% and not more than 6%.
20. A protective body, comprising: a plurality of the boron carbide sintered bodies according to claim 9 , and a substrate on which the sintered bodies are disposed.