In-Situ Synthesis And Oxidation Behaviors Of TiB₂-TiC_x Composites

In this paper, TiB₂-TiC_x and TiB₂-TiC_x/SiC multiphase ceramics are fabricated with TiH₂, B₄C and SiC powders by in situ synthesis under hot isostatic pressing (HIP). The preparation process and the performance have been conducted.In this paper, the pure titanium seals were used in order to avoid the molten glass permeating into sample. In this way, the success rate of the craft of HIP can be enhanced.Using the Ti-B-C ternary stable phase diagram and thermodynamic dates of some known materials at 1600℃, the unknown thermodynamic dates of some materials of this system were estimated. According to the conditions of thermodynamics phase equilibrium, it is calculated about the stabilized chemical potential of the Ti-B-C ternary system. It is one of theoretic analytic foundations in the reaction path of TiB₂-TiC_x multiphase ceramics fabricated with Ti and B₄C.The properties of TiB₂-TiC_x/SiC multiphase ceramics were studied, such as phases, grain size, relative densities, the hardness, and fracture toughness. The research indicates that the addition of SiC in TiB₂-TiC_x multiphase ceramics can be increased up to 15mol. If the addition of SiC islower than 15mol, the influence of SiC on TiB₂-TiC_x multiphase ceramics isnot prominent. The hardness of composite is 19.084GPa and fracture toughness is 4.121MPam^1/2. But once SiC is higher than 15mol, the relative densities, the hardness, and fracture toughness of the materials decrease deeply.The oxidized behaviors of TiB₂-TiC_x/SiC and TiB₂-TiC_x multiphase...