The mechanical and dielectric properties of Si3N4-based sandwich ceramics

Porous Si3N4/(Si3N4 + BN) sandwich ceramics were fabricated by tape casting and hot pressing. The layer thickness ratio, sintering temperature and sintering pressure affected the fracture strength, dielectric constant and porosity. The Si3N4/(Si3N4 + BN) sandwich ceramics with the layer thickness ratio of 1.5 sintered at 1450 °C with 5 MPa has a good comprehensive property of the fracture strength of 54.3 MPa and dielectric constant of 3.48 (at 1 GHz).