Glass–ceramic composites of the barium–sodium–niobate–silica system, with various amounts of Gd2O3 added, were synthesized
through melt casting followed by controlled crystallization. The phase transition, microstructure, microchemistry and dielectric performances
of the composites were characterized. The addition of 1 mol% Gd2O3 to the glass ceramics changed the dielectric constant
and breakdown strength remarkably, indicating that glass–ceramics with this composition are promising dielectric materials for high
energy storage density dielectrics.