ceramics-glass-refractories part2 Title: ceramics-glass-refractories_part2 Author: Internet Created

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Transcript of ceramics-glass-refractories part2 Title: ceramics-glass-refractories_part2 Author: Internet Created

  • CERAMICS, GLASS AND REFRACTORIESREFRACTORIES

    DR KASSIM AL-JOUBORY UNIVERSITY OF TECHNOLOGY

    BAGHDAD - IRAQ

  • 2) Materials Structure

    Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٢

  • Electronegativity X - is a measure of the strength with which an atom in a molecule attracts electrons

    Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٣

  • energy (kJ/mol)BondType of bond Ionic 50–1000 Covalent 200–1000 Metallic 50–1000 van der Waals 0.1–10 Hydrogen 10–40

    The building criteria for the crystal structure are Maintain neutralityMaintain neutrality Charge balance dictates chemical formula Achieve closest packing

    Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٤

  • IONIC CERAMICS

    Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٥

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٦

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٧

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٨

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٩

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٠

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١١

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٢

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٣

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٤

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٥

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٦

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٧

  • STRUCTURE OF CILICATES

    The general nature of silicate structures is the connection of the SiO44- tetrahedra. Additional oxides tend to break up the continuity of these tetrahedra. The remaining connectedness may be in the form of islands, chains or sheets: •Network silicate structures – these structures connect all 4 corners of the SiO44- tetrahedra to form a network. The Oxygen atoms are shared which accounts for the overall chemical formula of SiO2 not SiO4. of SiO2 not SiO4. •Island silicate structures – when positive ions bond with the oxygens of the SiO44- tetrahedral

    •Chain or ring silicate structures – when 2 corners of each SiO44- tetrahedra are bonded with corners of other tetrahedra with unit chemical formula SiO3-2. •Sheet silicate structures – when 3 corners in the same plane of a silicate tetrahedron are bonded to the corners of 3 other silicate tetrahedra with chemical unit Si2O5-2.

    Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٨

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq١٩

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٢٠

  • Dr. Kassim Al-joubory - University of Technology - Baghdad - Iraq٢١