Beta-Alumina Tube

Powers used commercial beta aluminas, Monofrax H fused brick and Alcoa XB-2 powder, as raw materials. These materials can be synthesized, with the addition of dopants for stabilizing the more conductive beta -alumina phase if desired, from the calcination of commercial aluminum salts or oxides with sodium carbonate or similar material. Beta-alumina and beta -alumina (magnesia- and/or lithia-stabilized) have both been satisfactorily deposited. 

During development of the process at General Electric the liquid used was pentan-l-ol (primary amyl alcohol), mainly because of its dielectric 

Electrophoretic deposition is most conveniently carried out by making the chamber wall the counter-electrode. The deposition process itself takes typically three minutes with an electric field of 7 x 10 V/m. Immediately following deposition the shape is placed in a low humidity drying oven to evaporate the liquid. With conventional drying techniques a few hours drying is necessary before the shape can be removed from the mandrel. 

Another characteristic of electrodeposited green shapes is their low green density, with close to 50% volume porosity, leading to the unusually 

In a recent study of zirconia-toughened alumina processed by two different routes a considerable difference in fracture toughness behavior was observed according to whether a mechanical or a wet diemlea1 

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Beta alumina tubes are not easy to fabricate satisfactorily, partly because of the stringent specification they must meet and partly on account of the intrinsic properties of the material itself. The specification includes ... 

Two general approaches have been adopted to the fabrication of electrolyte tubes (l) isostatic pressing (2) electrophoretic deposition. In either case the green tube must be sintered at high temperature in air in order to form and densify the beta alumina phase. 

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