Densification Mechanism of MgAl₂O₄ Spinel during Spark-Plasma-Sintering

Abstract:

The densification mechanism during the park-plasma-sintering (SPS) processing was examined in high purity MgAl2O4 spinel. As the density ρt increases, that is, as the effective stress σeff decreases, stress exponent n evaluated from σeff dependence of densification rate varies from n ≥ 4 in the low ρt region, n ≈ 2 in the intermediate ρt region to n ≈ 1 in the high ρt region. TEM observation shows that significant stacking faults caused by partial dislocations are observed in the low ρt region, but limited in the high ρt region. The ρt dependent densification behavior and microstructure suggest that the predominant densification mechanism during the SPS processing changes with ρt from plastic flow by partial dislocation motion for the low ρt region (n ≥ 4) to diffusion-related creep for the high ρt region (n ≈ 1).

• Periodical: Advances in Science and Technology (Volume 63)
• Pages: 62-67
• DOI: https://doi.org/10.4028/www.scientific.net/AST.63.62
• Online since: October 2010
• Authors: Koji Morita, Byung Nam Kim, Hidehiro Yoshida, Keijiro Hiraga, Yoshio Sakka
• Keywords: Densification Mechanism, Spark Plasma Sintering (SPS), Spinel

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