| 摘要 |
<p>A boron carbide based sintered compact having a four-point flexural strength of 400 MPa or more and a fracture toughness of 2.8 MPam1/2 or more; and two preferred embodiments of the boron carbide based sintered compact: (1) a boron carbide -titanium diboride sintered compact which is prepared by sintering a mixed powder of a B4C powder, a TiO2 powder and a C powder, while reacting them under pressure, comprises 95 to 70 mol % of boron carbide and 5 to 30 mol %, and contains boron carbide particles having a maximum particle diameter of 5 μm or less: and (2) a boron carbide-chromium diboride sintered compact which contains 10 to 25 mol % of CrB2 in B4C, has a relative density of 90 % or more, contains boron carbide particles having a maximum particle diameter of 100 μm or less, and exhibits an abundance ratio (area ratio) of boron carbide particles having a particle diameter of 10 to 100 μm to those having a particle diameter of 5 μm or less of 0.02 to 0.6.</p> |
