Method of etching to form cationically-conductive ceramic body

A process for producing a cationically-conductive ceramic body having an etched surface and a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity which comprises providing a cationically-conductive ceramic body having a specific resistivity at its surface portion significantly higher than its specific intrinsic resistivity, said ceramic body ranging in composition from an alkali metal beta-alumina phase to an alkali metal beta"-alumina phase including all combinations of said alkali metal beta-alumina phase and said alkali metal beta"-alumina phase, said alkali metal being selected from the group consisting of sodium, potassium, lithium, mixtures thereof and alloys thereof, and etching the surface portion of said ceramic body with phosphoric acid to produce said cationically-conductive ceramic body with a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity, said phosphoric acid having a concentration of P.sub.2 O.sub.5 which etches said ceramic body, said etching having no significant deleterious effect on said ceramic body.