Effect of Si₃N₄ nanowires on the mechanical properties and dielectric constant of porous Si₃N₄ ceramics

The high strength and low dielectric constant of silicon nitride (Si₃N₄) ceramics are an irreconcilable conflict. It is a compromise to introduce a suitable reinforcing phase in Si₃N₄ ceramics to receive well dielectric properties without excessive loss of mechanical properties. In this paper, Si₃N₄ nanowires were in-situ synthesized by pyrolysis of polysilazane with Si₃N₄ nanopowders as catalyst without introduction of impurities in Si₃N₄ porous ceramics. The formed Si₃N₄ nanowires not only improve the mechanical property but also reduce dielectric constant of porous Si₃N₄ ceramic.