Ceramic jacket protects thermocouple in high-temp applications

CaO-stabilized zirconia tube from Morgan Technical Ceramics can operate in furnace environments up to 2,000 °C, outlasting alumina alternatives.
February 15, 2011

Morgan Technical Ceramics (MTC), a manufacturer of ceramic, glass, precious metal, piezoelectric, and dielectric materials, has introduced a new thermocouple protection tube material made from CaO-stabilized zirconia. This material withstands a furnace’s maximum working temperature up to 2,000 °C.

The new zirconia thermocouple protection tubes offer corrosion and chemical resistance at higher temperatures than can be achieved with alumina tubes. Processes that use inert atmosphere and graphite can result in reduced oxygen in the alumina tubes, causing their early failure. The oxygen molecules in the zirconia will also be reduced in this environment, but at a much slower rate.

The material can be used in directional solidification system (DSS) furnaces, where temperatures are about 1,600 °C and the thermocouple tubes are sitting in a graphite bed. Alumina remains an appropriate material for use in other positions in the kiln, but zirconia thermocouples will have a longer life.

MTC offers a wide range of materials that can be used in temperature measurement, providing a solution for nearly every application. These include zirconia, mullite, alumina, and silicon carbide.

www.morgantechnicalceramics.com

Peter Welander, pwelander@cfemedia.com

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