Dielectric properties of silicon nitride ceramics produced by free sintering

Abstract

The silicon nitride ceramics with a beneficial combination of low dielectric losses and improved physical properties was fabricated by cold isostatic pressing and pressureless sintering. The fine grain microstructure, three-phase composition based on the β-SiAlON, the small amount of the glass phase and relatively small porosity promote a unique combination of a low thermal conductivity 14.51 W m¯¹ K¯¹ and low dielectric loss 1.4·10¯¯³. A novel method is proposed to overcome the main drawbacks of the commercial and high-cost technologies