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Influence of autogenous seeding on densification and microstructure in processing of γ-alumina nanopowders

Khodabakhshi, F ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. DOI: 10.1080/01411594.2010.514565
  3. Publisher: 2011
  4. Abstract:
  5. The effect of α-Al 2O 3 seeds and MgO on the densification behavior and microstructure of the nanocrystalline γ-Al 2O 3 powder was investigated. The required α-Al 2O 3 seeds were produced by 'autogenous seeding' where the seeds were obtained by calcination of the initial nanosized γ-Al 2O 3 powders above its transformation temperature and incorporated into γ-Al 2O 3 matrix. The seeds were characterized by means of laser particle size analyzer, X-ray diffraction, and Brunauer-Emmett-Teller surface analyzer. The simultaneous influence of α-Al 2O 3 seeds and MgO on γ-Al 2O 3 behavior was evaluated by differential thermal analysis, densitometry, and electron microscopy. The results showed that simultaneous presence of MgO and seeds in γ-Al 2O 3 matrix has a great impact on densification and microstructural evolution. The main role of MgO and the seeds are densification enhancement and grain refinement, respectively. The grain morphology is more equiaxed and desirably finer by using smaller seeds prepared using shorter calcination times
  6. Keywords:
  7. Nanopowder ; Al 2O 3 ; Ceramic ; MgO ; Nano powders ; Seeding ; Aluminum ; Calcination ; Ceramic materials ; Densification ; Differential thermal analysis ; Grain refinement ; Microstructure ; Nanostructured materials ; Particle size analysis ; X ray diffraction ; Seed
  8. Source: Phase Transitions ; Volume 84, Issue 1 , 2011 , Pages 1-14 ; 01411594 (ISSN)
  9. URL: http://www.tandfonline.com/doi/abs/10.1080/01411594.2010.514565