Mechanical and dielectric properties of porous Si3N4 ceramics using PMMA as pore former

Porous Si3N4 ceramics were prepared using PMMA as pore former, and the mechanical and dielectric properties were investigated, as a function of porosity. Higher porosity was achieved at lower sintering temperature with lower sintering additive and more PMMA. The flexural strength decreased exponentially with increasing the porosity and the pore size. The dielectric constant decreased with increasing the porosity and the frequency has less effect on the dielectric constant.