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Zirconia is an extremely refractory material. It offers chemical and corrosion inertness to temperatures well above the melting point of alumina. 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.
The fundamental properties of zirconia ceramic which are of interest to the engineer or designer are:
- High strength
- High fracture toughness
- High hardness
- Wear resistance
- Good frictional behaviour
- Non-magnetic
- Electrical insulation
- Low thermal conductivity
- Corrosion resistance in acids and alkalis
- Modulus of elasticity similar to steel
- Coefficient of thermal expansion similar to iron
Typical Uses of ZrO2:
- Precision ball valve balls and seats
- High density ball and pebble mill grinding media
- Rollers and guides for metal tube forming
- Thread and wire guides
- Hot metal extrusion dies
- Deep well down-hole valves and seats
- Powder compacting dies
- Marine pump seals and shaft guides
- Oxygen sensors
- High temperature induction furnace susceptors
- Fuel cell membranes
