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 strength of the agglomerates and subsequent consolidation. This paper focuses oil the origin of agglomerate strength for <10 nm sized boehmite (gamma-AlOOH) powders. The agglomerate strength of boehmite gel is (approximate to 23 MPa) more than three times higher than ethanol-dispersed boehmite agglomerate. Based on a series of experiments, it is demonstrated that solubility of the nanomaterials is largely responsible for in creased agglomerate resistance to deformation and powder consolidation. A model is presented to explain how agglomerate strength increases as a result of the enhanced solubility of nanosize particles and precipitation of the solute at particle contacts during drying. (C) 1997 Acta Metallurgica Inc.