Direct Characterizing of Densification Mechanisms during Spark Plasma Sintering

Chakravarty, Dibyendu and Chokshi, Atul H (2014) Direct Characterizing of Densification Mechanisms during Spark Plasma Sintering. In: JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 97 (3). pp. 765-771.

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Abstract

Spark plasma sintering (SPS) is a convenient and rapid means of producing dense ceramic compacts. However, the mechanisms responsible for rapid densification have not been identified satisfactorily, with different studies using an indirect approach yielding varied values for the densification parameters. This study involved SPS in high purity nanocrystalline alumina with temperatures ranging from 1173 to 1423K and stresses from 25 to 100MPa. A direct approach, with analyses at a constant density, revealed a stress exponent of similar to 1 and an inverse grain size dependence of similar to 3, consistent with Coble creep process. Whereas the direct approach gives a stress exponent of similar to 1, the indirect approach used previously gives stress exponents ranging from similar to 2.2 to 3.5 with the same data, thereby revealing potentially spurious values of the densification parameters from conventional indirect approaches to characterizing densification. The rapid densification during SPS is related to the finer grain sizes retained with the rapid heating rates and the imposed stress that enhances the driving force for densification.

Item Type:	Journal Article
Publication:	JOURNAL OF THE AMERICAN CERAMIC SOCIETY
Publisher:	WILEY-BLACKWELL
Additional Information:	Copyright for this article belongs to the WILEY-BLACKWELL,USA
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	12 May 2014 06:13
Last Modified:	12 May 2014 06:13
URI:	http://eprints.iisc.ac.in/id/eprint/48915

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