Abstract: Hydronium bonded polycrystalline shaped articles may be produced by the simple expedient of selecting a hydronium containing powder prepared by one of a plurality of prior art methods and then intermingling the hydronium powder with ortho-phosphoric acid to obtain a viscous mixture (resembling the consistency of toothpaste). The mixture is then formed into a predetermined shape, for example a disc or tube, and the shaped polycrystalline ceramic is allowed to cure. Curing may take place at an elevated temperature below 100.degree. C. for approximately 3 hours either as a step subsequent to forming, or as part of the forming step in 30 minutes at 120.degree. C. The result is bonded hydrogen conducting - hydronium, H.sub.3 O+, solid rigid structure with a smooth finish copying the mold from which it was shaped.