Microscopy and Microanalysis



Special Issue: Frontiers of Electron Microscopy in Materials Science

TEM Investigation of Nanophase Aluminum Powder


Valéry Y.  Gertsman  a1 c1 and Queenie S.M.  Kwok  a2
a1 Natural Resources Canada, CANMET, MTL, 568 Booth Street, Ottawa, ON K1A 0G1, Canada
a2 Natural Resources Canada, CANMET, CERL, 555 Booth Street, Ottawa, ON K1A 0G1, Canada

Article author query
gertsman vy   [PubMed][Google Scholar] 
kwok qsm   [PubMed][Google Scholar] 

Abstract

Nanophase aluminum powder was characterized in a field-emission-gun transmission electron microscope (TEM). Different techniques were used to investigate the structure of the particles, including conventional bright-field and dark-field imaging, scanning transmission electron microscopy (STEM), high-resolution lattice imaging, diffraction studies, energy dispersive X-ray spectroscopy (EDS) analysis and mapping, and electron energy loss spectroscopy (EELS) analysis and mapping. It has been established that the particle cores consist of aluminum single crystals that sometimes contain crystal lattice defects. The core is covered by a passivating layer of aluminum oxide a few nanometers thick. The alumina is mostly amorphous, but evidences of partial crystallinity of the oxide were also found. The thickness of this layer was measured using different techniques, and the results are in good agreement with each other. The particles are agglomerated in two distinct ways. Some particles were apparently bonded together during processing before oxidation. These mostly form dumbbells covered by a joint oxide layer. Also, oxidized particles are loosely assembled into relatively large clusters.

(Received December 1 2003)
(Accepted January 25 2005)


Key Words: analytical TEM; HREM; EELS; EDS; aluminum nanopowder; alumina; passivating layer thickness.

Correspondence:
c1 Corresponding author. E-mail: Val.Gertsman@NRCan.gc.ca