Advanced Powder Technology, Vol.31, No.7, 2742-2748, 2020
Synthesis of the porous spinel Co-Al2O4 powder produced by ball milling and annealing
Ball milling (BM) of elemental Co and Al was conducted for 30 h (h). This process has altered the original morphologies of both elemental Co and Al powders. Spherical Al powder particles has changed into a smooth pancake-shape while the original irregular-shaped Co agglomerates became disintegrated ultrafine particles. BM of the Co20 wt.% Al powder mixture after 30 h yielded thin irregular-shaped particles. XRD analysis revealed a partial structural transformation after BM and further structural change upon annealing the powder at 600 degrees C, as confirmed by the SEM images. The formation of the cubic spinel superstructure with lattice parameter a = 8.066 angstrom (ZnAl2O4 prototype) and Fd-3 m # 227 space group was realized. By means of LEO 1525 field-emission scanning electron microscope (FE-SEM), a fibrous mesoporous structure was revealed on the milled powder after annealing the Co-Al mixture at 600 degrees C. The EDS analysis confirmed a minor N impurity on the annealed powder. 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.