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Analysis of the crystal phases of Na+-beta-aluminas synthesized by infiltration of alkali molten salts

“…Smaller particles are less massive so gravity has less effect, reducing packing density. [17] The pre-heated a-Al to Na-b/b 00 -Al 2 O 3 occurred in all the pre-forms (Fig. 4).…”

Impact of Liquid Phase Formation on Microstructure and Conductivity of Li-Stabilized Na-β″-alumina Ceramics

“…From the binary phase diagram in Figure S4, the coexistence of β″-alumina with NaAlO 2 is expected, but the characteristic reflections of this latter phase are not observed. Instead, reflections at similar positions are commonly ascribed to the 106 and 107 peaks of β-alumina. ,, Due to the similar building blocks of β-alumina and β″-alumina, many other reflections overlap for these two closely related structures. In the literature, quantification of the β″-alumina fraction is thus often not based on Rietveld refinement of the full diffraction pattern but on the comparison of intensities of these (or other) reflections.…”

Structure and properties relationships of beta-Al2O3 electrolyte materials

“…Stabilization of ␤"-phase was basically the substitution of Al 3+ ions by the cations of stabilizers to compensate extra Na + ions. It had been reported that the compensating Li + ions generally substituted the octahedral Al 3+ ions, and Mg 2+ ions substituted tetrahedral Al 3+ in the spinel blocks [11]. Hence, the A Al(VI) /A Al(IV) decreased in the Li + -stabilized system, but increased a little in the Mg 2+ -stabilized system.…”

“…This indicated that LiAl 5 O 8 -stabilized system could produce more ␤"-phase in comparison with the Li 2 CO 3 -stabilized compositions. It had been reported that LiAl 5 O 8 had more volume than Li 2 CO 3 [11], therefore LiAl 5 O 8 could induce more uniform distribution of Li + ions and increase the fractions of ␤"-phase during the preparation process. Obviously, the stabilization effect in the LiAl 5 O 8 -Mg(OH) 2 -stabilized system was better than that of the Mg(OH) 2 -stabilzed system, but worse than that of the LiAl 5 O 8 -stabilzed system.…”