“…20 Various approaches have been applied to prevent undesirable aggregation of the nanoparticles during precipitation from solution, as well as during the following drying and thermal treatment, such as addition of organic solvents, surfactants, or chelators. 3,8,11 Even though these dispersants can improve the colloid stability, reduce the temperature required for sintering, enhance green densication, and control the particle morphology, 8 they affect the product crystallinity and are difficult to completely remove from the nal materials. 10 In this context, phase transformation of ammonium aluminium carbonate hydroxide to alumina can be helpful to suppress agglomeration, because the CO 2 , NH 3 , and H 2 O gases released during thermal treatment play signicant roles in reducing agglomeration of the nal Al 2 O 3 particles.…”