Boron carbide ceramic and manufacturing method thereof
View Patent ↗Boron carbide ceramics produced by spark sintering methods have more desirable mechanical properties than conventionally produced carbides. The boron carbide ceramics include amorphous boron, amorphous carbon, and Al 2 O 3 powder as a sintering aid. The boron carbides may also contain a carbon nano fiber in a nearly homogeneously dispersed state. The sintered compact has a relative density of a boron carbide ceramic of approximately not less than 99%. The boron carbide ceramics are prepared preferably by subjecting a mixed powder of the starting raw materials and the carbon nano fiber to simultaneous synthesis and sintering using the spark plasma sintering method.
1. A boron carbide ceramic prepared from a raw material mixture comprising an amorphous boron, an aluminum oxide powder, and carbon nano fibers,
wherein the boron carbide ceramic has a relative density of approximately not less than 99%, and the carbon nanofibers are nearly homogeneously dispersed throughout the boron carbide ceramic.
2. The boron carbide ceramic of claim 1 , wherein the boron carbide ceramic contains 3% to 15% by volume of the carbon nano fibers.
3. The boron carbide ceramic of claim 1 , wherein the raw material mixture further comprises an amorphous carbon powder.
4. The boron carbide ceramic of claim 1 , wherein the boron carbide ceramic is prepared via spark plasma sintering.
5. A method for manufacturing a boron carbide ceramic, comprising:
providing an amorphous boron powder and an aluminum oxide powder;
dispersing carbon nano fibers in water or alcohol to form a mixture;
mixing the first mixture with the amorphous boron and the aluminum oxide powders to form a second mixture;
drying the second mixture to obtain a mixed powder;
pressing the mixed powder; and
heating the mixed powder to raise the temperature thereof by spark plasma sintering, wherein said boron carbide ceramic has a relative density of approximately not less than 99%.
6. The method of claim 5 , wherein the boron carbide ceramic contains 3% to 15% by volume of carbon nanofibers.
7. The method of claim 5 , wherein the spark plasma sintering comprises heating the mixed powder in a near vacuum of not more than 10 Pa while pressing the mixed powder at a pressure of 10 MPa to 100 MPa at a temperature of 1,500° C. to 1,900° C. for 1 min. to 60 min.
8. The method of claim 5 , further comprising providing an amorphous carbon powder with the amorphous boron powder and the aluminum oxide powder.