Effects of Crystallinity of NH₄AlO(OH)HCO₃ on the Sinterability of α-Alumina

Abstract

Effect of crystallinity of parent salt on the sinterability of α-alumina has been studied. Two series of NH₄AlO(OH)HCO₃ tentatively designated as I- and R-series, were prepared under the different conditions.
It is shown that the sinterability of the α-alumina powders of I-series increased with decreasing crystallinity of the parent salt. Alpha-alumina powder of the R-series, on the other hand, exhibited the sinterability comparable to that of poor-crystallized I-series powders in spite of the good crystallinity. This is explained in terms of the well-dispersed nature of the primary particles of parent salt.