Patent ID: 7309672
Filing Date: 2007-12-18
Classification: C04B

Abstract:
1. A substantially pore-free, sintered body comprising from about 90% by weight to about 99% by weight of boron carbide, having a B:C atomic ratio ranging from 3.8 to 4.5:1, 0 to 1% by weight free carbon, 0 to 1% by weight BN or AlN, remainder an oxide binder phase; said sintered body having a density of not more than 2.60 g/cm 3 , a substantially uniform microstructure composed of substantially, equiaxed grains of said boron carbide, having a mean grain size within the range of from 0.7 to about 12 μm; the oxide binder phase comprising at least a rare earth aluminate; the binder phase being present in a form of accumulations at multiple grain junctions, said sintered body having a porosity of not more than 1%, hardness (Knoop, 300 g) greater than 2400; four-point flexural strength of at least 400 MPa; and fracture toughness of at least 3.0 MPa·m 1/2 measured by the Chevron Notch method.