Effect of the Addition of Carbon on the Sintering Properties of Boron Carbide Ceramics prepared by Pressureless Sintering

Effect of the addition of carbon on the sintering properties of pressureless sintered boron carbide ceramics was investigated by using carbon black and phenolic resins as the main additives. There were three ways for adding Carbon, carbon black adding, phenolic resins adding and adding carbon black and phenolic resins mixtures. The density and microstructure of sintered B4C ceramics were analyzed by densitometer and optical microscope respectively. The effect on the densification of B4C ceramics by different content and adding method of carbon were analyzed and summarized. The results showed that the B4C ceramics has the optimum properties, that bulk density, bending strength, hardness and fracture toughness achieve 2.42g/cm(3),335MPa, 22Gpa and 3.17 Mpa.m(1/2), respectively under the adding the mixture of 5.5%, carbon black and 1.5%, phenolic resins.