Experiments were conducted to fabricate nano-crystalline ceramic thin films (membranes) using polymeric resin precursors. Two different NASICON compositions were chosen for fabrication: (1) NaZr,Si,P3-,012, and (2) NaZrsSixP3-xO12 and (2) Na1+xSn2-xInxP3O12-Zirconium-containing resins could not be synthesized without precipitations; however, clear resins were successfully generated using a tin-based composition (NaSn2P3O12). The fin-based resins were spin-coated onto silicon substrates and then heated (calcined) to high temperatures using ozone as an oxidant. Optimum resin viscosity, spin coating, and calcination conditions were developed. The resulting thin films were characterized using X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) techniques. Fully-oxidized, single phase, crack-free films were generated that were approximately 80-100 nanometres thick containing crystalline grains about 5-10 nanometres in diameter after calcining at temperatures of about 600 degrees C to 700 degrees C. These grain sizes did not correlate with those measured in "chunks" of resins that were calcined using the same conditions. Therefore, thin films of the Sn-NaSICON precursor coatings appear to provide physical constraints that are conducive to the formation of nano-crystals at temperatures of about 600 degrees C to 700 degrees C. Enhanced transport of the ions in the nano-crystalline grain boundaries at relatively low temperatures is predicted. The films should prove suitable for ion exchange of the sodium ions with protons where the resulting enhanced conductivity could lead to practical devices, including: hydrogen separation membranes, fuel cells, hydrogen "pumps", electrolyzers, thermoelectric generators, electrochemical reactors, and sensors.

Keywords: inorganic membrane; nano-crystalline; thin-film; NASICON; proton