The influences of heat treatment on the structural properties of lithium aluminates

Two synthesis routes, sol precipitation and sol gelation, using aluminum isopropoxide and lithium nitrate as precursors have been used to prepare lithium aluminate. The sol precipitation method (LISOL) produced a mixture of gamma -LiAlO2 and LiAl5O8, and sol gelation (LIGEL) produced pure gamma -LiAlO2, both at 750 degreesC. The density and specific surface area of the ceramic powders calcined at 1150 degreesC were 2.72 g cm(-3) and 6 m(2) g(-1), respectively, for the powders obtained by sol precipitation and 2.47 g cm(-3) and 2 m(2) g(-1), respectively, for the powders obtained by sol gelation. The synthesized powders presented thermal stability over 600 degreesC and the sintering process occurred in the temperature range of 600-1400 degreesC. The absorbed heat by the material in this temperature range during DTA/TG experiment showed that the sintering process was more efficient when the powders were previously calcined over 550 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.