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Densification mechanisms in spark plasma sintering of nanocrystalline ceramics

Chaim, Rachman (2007) Densification mechanisms in spark plasma sintering of nanocrystalline ceramics. MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 443 (1-2). pp. 25-32.

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Official URL: http://www.sciencedirect.com/science?_ob=ArticleUR...

Abstract

Effect of the particle size on the possible electric discharge during the SPS was examined. Nanoparticle compacts enable accumulation of high electric charge, and discharge under conventional voltages used for the SPS. The critical particle size for the electric discharge is both morphological and material dependent. The early stages of densification of the nanocrystalline powder compact proceed either by the plastic deformation or grain-rotation coalescence and sliding, aided by softening of the particle surfaces. The active densification mechanism depends on the changes both in the mechanical and electrical properties with temperature. Densification of 11 nm nc-MgO particles with low yield stress proceeds by plastic deformation already at 700 °C. However, densification of 34 nm nc-YAG particles with high yield stress proceeds by nano-grain rotation aided by particle surface softening. Densification at the final stages of SPS is associated with diffusional processes, where curvature driven grain growth predominates.

Item Type:Article
Uncontrolled Keywords:densification; spark plasma sintering (SPS); ceramic; nanocrystallme; nanoparticle; MgO
Subjects:Physical Science > Nanophysics
Material Science > Nanostructured materials
ID Code:2629
Deposited By:Anuj Seth
Deposited On:27 May 2009 12:20
Last Modified:27 May 2009 12:20

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