Oxidation behavior of graphene nanoplatelet reinforced tantalum carbide composites in high temperature plasma flow

    Authors

    A. Nieto; A. Kumar; D. Lahiri; C. Zhang; S. Seal;A. Agarwal

    Comments

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    Abbreviated Journal Title

    Carbon

    Keywords

    CERAMIC COMPOSITES; ABLATION BEHAVIOR; ZIRCONIUM; HAFNIUM; TAC; POWDERS; Chemistry, Physical; Materials Science, Multidisciplinary

    Abstract

    Graphene nanoplatelets (GNP) reinforced tantalum carbide (TaC) composites are exposed to a high temperature plasma flow in order to evaluate the effects of GNP on the oxidation behavior of TaC at conditions approaching those of hypersonic flight environments. The addition of GNP is found to suppress the formation of the oxide layer by up to 60%. The high thermal conductivity of GNPs dissipates heat throughout the sample thereby reducing thermal gradients and reducing the intensity of heating at the surface exposed to plasma. In addition, GNPs enhance oxidation resistance by providing toughening which suppresses crack formation and bursting that accelerates oxidation. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) reveal that GNPs have the ability to survive the intense high temperature of the plasma. GNPs are believed to seal oxide grain boundaries and hinder the further influx of oxygen. GNPs also provide nano sized carbon needed to induce the localized reduction of Ta2O5 to TaC. Micro computed X-ray tomography (MicroCT) validates that the above mechanisms protect the underlying unoxidized material from the structural damage caused by thermal shocks and high shear forces, by reducing thermal gradients and providing toughness. (C) 2013 Elsevier Ltd. All rights reserved.

    Journal Title

    Carbon

    Volume

    67

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    398

    Last Page

    408

    WOS Identifier

    WOS:000329379300043

    ISSN

    0008-6223

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