STP153: Effect of Temperature on the Electrical Resistivity of Several Ceramic and Silicone-Type Coatings

    Strauss, Simon W.
    Inorganic Chemist, Physicist, and Ceramic Engineer, Enameled Metals Section, National Bureau of StandardsWashington, D. C.,

    Richards, Lloyd E.
    Inorganic Chemist, Physicist, and Ceramic Engineer, Enameled Metals Section, National Bureau of StandardsWashington, D. C.,

    Moore, Dwight G.
    Inorganic Chemist, Physicist, and Ceramic Engineer, Enameled Metals Section, National Bureau of StandardsWashington, D. C.,

    Pages: 8    Published: Jan 1954


    Abstract

    The electrical resistivity of sheet mica, a ground coat porcelain enamel, two alkali-free ceramic coatings, a silicone varnish, and a coating consisting of a silicone varnish mixed with ground mica was measured in the temperature range 100 to 500 C and at an applied direct current potential of 200 v. A plot of the logarithm of the resistivity versus the reciprocal of the absolute temperature for each of these materials showed that marked deviations from the Rasch-Hinrichsen law occurred only with silicone and silicone-mica coatings. The electrical resistivity of all coatings tested was found to be independent of coating thickness and of duration of aging at 200 C. The measured resistivities in ohm-cm of the materials when tested at 400 C were (a) silicone-mica coating, 1400 × 108, (b) mica, 320 × 108, (c) silicone varnish coating, 280 × 108, (d) alkali-free ceramic coating, 1.6 × 108, and (e) ground coat enamel, 0.0025 × 108.


    Paper ID: STP47977S

    Committee/Subcommittee: B08.13

    DOI: 10.1520/STP47977S


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