Compositional Modification of Hot‐Pressed Silicon Nitride by High‐Temperature Electrolysis

Impurities and additives used in the liquid‐phase densifica‐tiondensification of silicon nitride ceramics are preferentially partitioned to the residual intergranular glass phase remaining in these materials. On the basis of a simple phenomenological ionic migration model, it is proposed and demonstrated that a high‐temperature electrolysis treatment may be used to modify the concentration of both the additive and impurities. The compositional modification has a number of consequences and, as an illustration, the improvement in high‐frequency dielectric loss produced as a result of the electrolysis treatment is presented.