Compositions: ceramic – Ceramic compositions – Carbide or oxycarbide containing
Reexamination Certificate
2006-12-29
2008-10-28
Group, Karl E (Department: 1793)
Compositions: ceramic
Ceramic compositions
Carbide or oxycarbide containing
C501S096300, C264S649000, C264S658000
Reexamination Certificate
active
07442661
ABSTRACT:
A boron carbide based sintered body having a four-point flexural strength of at least 400 MPa and a fracture toughness of at least 2.8 MPa·m1/2, which has the following two preferred embodiments. (1) A boron carbide-titanium diboride sintered body obtained by sintering a mixed powder of a B4C powder, a TiO2powder and a C powder while reacting them under a pressurized condition and comprising from 95 to 70 mol % of boron carbide and from 5 to 30 mol % of titanium diboride, wherein the boron carbide has a maximum particle diameter of at most 5 μm. (2) A boron carbide-chromium diboride sintered body containing from 10 to 25 mol % of CrB2in B4C, wherein the sintered body has a relative density of at least 90%, boron carbide particles in the sintered body have a maximum particle diameter of at most 100 μm, and the abundance ratio (area ratio) of boron carbide particles of from 10 to 100 μm to boron carbide particles having a particle diameter of at most 5 μm, is from 0.02 to 0.6.
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Hirao Kiyoshi
Kanzaki Shuzo
Sakaguchi Shuji
Yamada Suzuya
Yamauchi Yukihiko
Denki Kagku Kogyo Kabushiki Kaisha
Group Karl E
National Institute of Advanced Industrial Science and Technology
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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