beta " -Alumina, the electrolyte of choice of sodium/sulfur and sodium/metal chloride batteries and alkali-metal thermal-electric converters, was sintered from precursor phases to high beta " -phase purity in less than 15 s from the onset of densification by rapid pass-through rf induction coupled plasma sintering, The maximum instantaneous shrinkage rate was 1.8%/s, The resisivity was measured to be 13.8 +/- 1.4 Omega (.)cm. The rapid conversion found is a significant improvement over conventional processing of beta " -alumina, which requires extended postsintering annealing times to obtain high beta " -phase purity.