Spark plasma sintering of tungsten–yttrium oxide composites from chemically synthesized nanopowders and microstructural characterization

Mazher Ahmed Yar, Sverker Wahlberg, Hans Bergqvist, Hanadi G Salem, Mats Johnsson, Mamoun Muhammed

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Nano-crystalline W-1%Y2O3 (wt.%) powder was produced by a modified solution chemical reaction of ammonium paratungstate (APT) and yttrium nitrate. The precursor powder was found to consist of particles of bimodal morphology i.e. large APT-like particles up to 20 μm and rectangular yttrium containing ultrafine plates. After thermal processing tungsten crystals were evolved from W–O–Y plate like particles. spark plasma sintering (SPS) was used to consolidate the powder at 1100 and 1200 °C for different holding times in order to optimize the sintering conditions to yield high density but with reduced grain growth. Dispersion of yttrium oxide enhanced the sinterability of W powder with respect to lanthanum oxide. W–1%Y2O3 composites with sub-micron grain size showed improved density and mechanical properties as compared to W–La2O3 composites. Sample sintered in two steps showed improved density, due to longer holding time at lower temperature (900 °C) and less grain growth due to shorter holding time at higher temperature i.e. 1 min at 1100 °C.
    Original languageEnglish
    Pages (from-to)227-332
    Number of pages6
    JournalJournal of Nuclear Materials
    Volume412
    Issue number2
    DOIs
    Publication statusPublished - May 2011

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