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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/028/02/0109-0114

    • Keywords

       

      YSZ powder; dispersion behaviour; grindability.

    • Abstract

       

      A precursor for zirconia – 8 mole% yttria (YSZ–ZrO2–8 m% Y2O3) powder was prepared by coprecipitation and the calcination temperature was fixed as 900°C from TG–DTA and XRD studies. The calcined powder could be dry ground only to a mean particle size (𝐷50) of 6 𝜇m containing substantial amount of coarse agglomerates in the size range 10–100 𝜇m. The dispersion conditions for its wet grinding were evaluated through zeta-potential and viscosity studies. The zeta-potential variation with pH of the aqueous suspensions of the powder exhibited maximum numerical values at 3 and 11 pH, exhibiting the ideal pHs for dispersion stability through electrostatic columbic repulsion mechanism. Slurries of dry ground powders with solid concentration in the range 15–30 vol.% exhibited pseudo-plastic flow characteristics, indicating presence of flocculates. With progress of grinding, the increase in viscosity of the slurries became less significant with decreasing solid concentration. Even though the particle size of the ground slurries decreased with decreasing solid content, there was little change in it for slurries with solid content < 20 vol.%. Grinding conditions for formation of sinter-active powders of YSZ with sub-micron size (𝐷50\ ∼ 0.7 𝜇m free of agglomerates of size > 5 𝜇m) were established. Compacts from this powder could be sintered at 1400°C to translucent bodies with 99% theoretical density.

    • Author Affiliations

       

      S Ramanathan1 K P Krishna Kumar1 2 P K De1 S Banerjee1

      1. Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
      2. Summer Research Fellow of the Indian Academy of Sciences

    • Dates

       
      Published
      April 2005
      Manuscript received
      15 May 2004
      Manuscript revised
      12 January 2005

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

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      Posted on July 25, 2019

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