THE EFFECT OF PARTICLE SOLUBILITY ON THE STRENGTH OF NANOCRYSTALLINE AGGLOMERATES - BOEHMITE

Nanosized powders readily agglomerate during processing and handling. The strength of the interparticle bonds can dramatically affect the st rength of the agglomerates and subsequent consolidation. This paper fo cuses oil the origin of agglomerate strength for <10 nm sized boehmite (gamma-AlOOH) powders. The agglomerate strength of boehmite gel is (a pproximate to 23 MPa) more than three times higher than ethanol-disper sed boehmite agglomerate. Based on a series of experiments, it is demo nstrated that solubility of the nanomaterials is largely responsible f or in creased agglomerate resistance to deformation and powder consoli dation. A model is presented to explain how agglomerate strength incre ases as a result of the enhanced solubility of nanosize particles and precipitation of the solute at particle contacts during drying. (C) 19 97 Acta Metallurgica Inc.