Reduction in α-transformation temperature of gibbsite and boehmite by powder mixing with seed

Addition of fine alpha -alumina powder as a seed by up to 50 wt% to a gibbsite (Al(OH)(3)) powder sample enables it to reduce its alpha -transformation temperature from about 1360 to 1090 degreesC. Intensive mixing of the sample with 50 wt% seed using a planetary mill lessens the alpha -transformation temperature further down to around 910 degreesC. A similar trend can be seen in the boehmite sample. The intensive mixing (grinding) of these samples by the planetary mill is accompanied with their size reduction, dispersing fine particles that play a significant role to reduce the cr-transformation temperature in the calcination stage.