• Phase analysis and dielectric properties of oxides obtained in the MgO–(1−x)Nb2O5–(x)Ta2O5 system

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      https://www.ias.ac.in/article/fulltext/jcsc/113/05-06/0603-0610

    • Keywords

       

      Ceramics; electronic materials; oxides

    • Abstract

       

      MgNb2-xTaxO6 (0 ≶x ≶ 2) phases can be obtained as the major phase (75 to 90%) by solid state reactions starting from oxides. These oxides crystallize in the orthorhombic columbite structure tillx = 1.75 and the tetragonal trirutile structure for MgTa2O6 (x = 2.0). For all the compositions there exist secondary phases like Nb2O5 or Ta2O5 in addition to the major AB2O6 phase. Sintered disks (1200°C) show dielectric constants varying between 14.8 and 16.0 for the entire range of composition at a frequency of 500 kHz. The dielectric loss is nearly constant around 0025 to 003 between 0 ≶x ≶ 1 but increases to 017 for the MgTa2O6 phase (x = 2.0). Scanning electron micrographs reveal a gradual decrease in grain size with increase in Ta concentration with a size of 3 micron forthe x=0 composition (sintered at 1200°C) while thex = 2 phase shows a grain size of approximately 0.5 microns. The microwave dielectric constant at ∼14 GHz is found to be 20.9 for thex = 0 composition and 17.7 for thex = 2 composition.

    • Author Affiliations

       

      M Thirumal1 A K Ganguli1

      1. Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi - 110 016, India
    • Dates

       
  • Journal of Chemical Sciences | News

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