Microstructure and Mechanical Properties of SiC-Materials Sintered in the Liquid Phase with the Addition of a Finely Dispersed Agent

Resumo

The free liquid phase sintering method was applied to obtain dense (relative density 99.5%) materials based on silicon carbide. A eutectic mixture of MgO, Y₂O₃ and Al₂O₃ of the composition corresponding to the coexisting garnet – spinel phase curve was used as the sintering agent. In the preparation of the charge powders, the method of chemical deposition from salt solutions was used, that produced eutectic composition oxides uniformly distributed on the silicon carbide powder particles. The materials produced show good mechanical properties: elastic strain energy 410 GPa, flexural strength 680 MPa, K_Ic = 6.0 MPa·m^1/2, HV 21.5 GPa, the values of which are close to the corresponding indices for the hot-pressed carbide-silicon materials.