Effect of chemical vapor infiltration of Si3N4 on the mechanical and dielectric properties of porous Si3N4 ceramic fabricated by a technique combining 3-D printing and pressureless sintering

Porous Si3N4 ceramic with a porosity higher than 70% is fabricated by a technique combining three-dimensional printing and pressureless sintering. Using chemical vapor infiltration (CVI) of Si3N4, the mechanical properties of the porous Si3N4 ceramic are clearly improved by increases in the connection strength among β-Si3N4 particles and the loading ability of β-Si3N4 particles. The porous Si3N4 ceramic after CVI of Si3N4 is an excellent wave-transparent material due to its good mechanical properties and excellent dielectric properties.