Microstructural evolution of Al2O3-ZrO2 (Y2O3) powder de-agglomerated by sodium hydroxide solution soaking

Al2O3-ZrO2 (Y2O3) AZY nano-composite powder with a microstructure of zirconia grains buried in amorphous alumina was prepared by a novel co-precipitation method. Hard agglomerates in the powder can be easily broken down as a result of the amorphous alumina on the surface of primary particles, which is soluble in NaOH solution. 98.9% relative density was reached at 1300 degrees C, and grain abnormal growth emerged accompany with density decrease at 1550 degrees C for the de-agglomerated AZY composite powder. A small amount of sodium impurity residual in NaOH solution treated powder developed a dense microstructure with alumina grain in platelet shape at 1300 degrees C. The morphology and size of alumina platelet did not change much with the sintering temperature increasing. (C) 2015 Elsevier B.V. All rights reserved

Investigation on the preparation and properties of monodispersed Al2O3-ZrO2 nanopowder via Co-precipitation method

With Al2O3 as inhibitor (which can be etched after calcination), monodispersed Al2O3-ZrO2 nanopowder was successful prepared by co-precipitation method. The as-prepared powders were characterized by acoustic particle sizer (APS), SEM, TEM and XRD, respectively. Crystalline and non-agglomerated nanometric Al2O3-ZrO2 powders with very small crystallite size (similar to 7 nm) and narrow size distribution can be obtained. The relative yield was effected dramatically by pH and the ratio of M-AHC: M-Zr. Green bodies have an ultrafine uniform microstructure without apparent macropore through 200 MPa CIP treatment. The relative density of the grains can be reached to similar to 98.2% by sintering at 1050 degrees C for 4 h, with an average grain size degrees 39 nm. (C) 2016 Elsevier B.V. All rights reserved