Zirconia Oxide Ceramics could be used at higher temperature. Ceramic maintains mechanical properties at high temperature, so full ceramic bearing can be used at elevated temperature. Full ceramic bearing are more suitable for chemical industry application. Zirconia Ceramics are more suitable for temperature-variation application. Because thermal expansion co-efficiency of ceramic are smaller than metal, so the change of clearance of full ceramic bearing is smaller than that of metal bearing. And it has more resistance to seizing due to smaller thermal expansion. Full ceramic bearing could work under poor lubrication, because ceramics are self-lubrication. Full ceramic bearing could be used at high-vacuum environment. Zirconia Oxide Ceramics could be used as insulation bearing and can prevent Electrical Arcing because ceramics is not electrical conductor.
Pure zirconia exists in three crystal phases at different temperatures. At very high temperatures (>2370°C) the material has a cubic structure. At intermediate temperatures (1170 to 2370°C) it has a tetragonal structure. At low temperatures (below 1170°C) the material transforms to the monoclinic structure. The transformation from tetragonal to monoclinic is rapid and is accompanied by a 3 to 5 percent volume increase that causes extensive cracking in the material.
Zirconia is an extremely refractory material. It offers chemical and corrosion inertness to temperatures well above the melting point of alumina. Zirconia Oxide Ceramics could be used in magnetic environment because ceramics do not respond to magnetic forces. The material has low thermal conductivity. It is electrically conductive above 600°C and is used in oxygen sensor cells and as the susceptor (heater) in high temperature induction furnaces. With the attachment of platinum leads, nernst glowers used in spectrometers can be made as a light emitting filament which operates in air.
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