Beta”-alumina additives

On a laboratory-prepared specimen comparable to corundum brick, the presence of beta-alumina in addition to sodium aluminate was noted. However, beta-alumina was formed above 1300°C. Unlike Yamaguchi [28], Rigby and Hutton [29] did not differentiate as to which was the major or minor reaction point. 

In the case of zirconia, however, the impedance spectmm is more complex than beta-alumina s. There is, at high measnrement freqnencies, an additional semicircle that might be dne to intragranular condnction, which is an intrinsic conduction mechanism. 

Binner, J.G.P. and Stevens, R., Improvement in the Mechanical Properties of Polycrystalline Beta-Alumina Via the Use of Zirconia Particles Containing Stabilizing Oxide Additions. J. Mat. Sci. 20 3119-3124 (1985). 

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. 

Various kinds of Zeolites are engaged in the catalytic cracking of hydrocarbon feedstocks, such as ZSM-5, Beta, Y, in addition to other known acid solids such as silica-alumina, alumina and clays. Various combinations of these catalysts such as SAHAyZSM-5 and MCM-41/ZSM-5 have been also employed for the recycling of polyolefins [30]. 

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