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Mixing of raw materials |
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In
1998 mixing of raw materials was done in 2 litre bottles.Today
mixing is performed in 100 litre barrels, which weigh more than
300 kg
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Calcination
of raw materials |
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The
mixed raw materials are dried and calcined to form the pure ferroelectric
phase
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Milling
of ferroelectric powder |
 |
Today
milling is performed in vibration mills with 50-200 kg powder
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Spray-drying
of ferroelectric powder
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NIRO Lab-scale equipment |
In 1998, spray-drying was performed in NIRO Lab-scale
equipment.
Today spray-drying
is performed in a NIRO industrial model.
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NIRO industrial model
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Dry-pressing
of ceramic pieces |
 |
Pieces
are formed by uniaxial dry-pressing of the spray-dried powder.
The flow characteristics and binder content in the spray-dried
powder is the most determining factor for the porosity of the
finished products.
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Binder-burnout
and Sintering |
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The binder is burned out in large furnaces in oxidising
atmosphere. Then the parts are sintered to a dense structure
in furnaces with controlled atmosphere.
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Machining
of sintered parts |
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Parts are machined to fulfil tolerances
down to +/- 1/100 mm on all dimensions:
- Thickness
- Diameter
- Length/Width
-
Inner/Outer diameter
- Radius of curvature
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Electroding
and Poling |
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Electrodes
of various metals are applied by the following processes:
-
Screen printing
- Evaporation
-
Chemical deposition
Polarisation is performed
at 100-200 o
C in oil baths. Electrical fields of 1-4 kV/mm are applied. |
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