Semi-Conducting Glazes Based on Cassiterite Crystalline Phase for Porcelain Insulators Applications: Phase Evolution, Microstructure and Electrical Properties

ABSTRACT

Two series of semi-conducting glazes based on cassiterite phase were prepared and characterized after application on electrical porcelain bodies. In one series, semi-conducting fraction of the final glazes was calcined, then added to the base glaze. In another series, semi-conducting fraction of the studied glazes was precipitated in-situ during firing. Morphology of cassiterite and its optimized content in the studied glazes were found as the most important parameter affecting electrical properties of final glazes. Maximum amount of cassiterite was achieved for the first series containing whole calcined semi-conducting constituent. Band gap of this glaze was found to be 2-2.6 eV. Surface resistance of insulator bodies coated with cassiterite based semi-conducting glazes was obtained 10⁵-10⁷ times more than that of the common glazes, indicating a uniform charge distribution and inhibition of partial discharge through surface of insulator.

GRAPHICAL ABSTRACT

Keywords:

• Semi-conducting glaze
• Cassiterite
• Porcelain insulators
• Electrical properties