Synthetic Cordierite

Hochtemperatur Presskeramit aus Cordierit

Pressed Technical Ceramics: Synthetic Cordierite

Pressed ceramic products complete the range of ceramics supplied by Final Advanced Materials. This range is suitable for applications which are subject to less severe constraints. The requisite properties for these applications are achieved by firing to a temperature in excess of 1,000 °C, i.e. a temperature which is lower than that required for the production of sintered or machinable ceramics.

Parts are produced by shaping in dry presses, by a liquid method, or by extrusion. Treatment is possible in the raw state.

Two types of synthetic cordierite, by opposition to natural cordierite which is used in machinable ceramics, are avalaible:

Non-Pourous Cordierite

Non-porous cordierite is a rock which is equally at home in jewellery as in the refractory industry. It has multiple qualities: low thermal conductivity and a low coefficient of expansion, resistance to heat, low dielectric losses, resistance to corrosion, particularly by molten metals, and excellent high-pressure vacuum withstand. Moreover, its limited thermal expansion is beneficial for components with stringent tolerances.

Porous cordierite

Porous cordierite shares numerous properties with normal cordierite. However, it has a lower mechanical resistance. Its porosity nevertheless permits the more effective accommodation of thermal impacts.

Applications of Cordierite Pressed Technical Ceramics

  • Support for heating conductors
  • Spark protection
  • Gas engineering
  • Electric heating systems
  • Components for cartridge heaters
  • Electric heat accumulators
  • Electrical resistors

Benefits of Cordierite Pressed Technical Ceramics

  • Hardness
  • High mechanical resistance
  • Dimensional stability, even at high temperatures
  • Resistance to wear and corrosion
  • Electrically insulating
  • High-temperature withstand
  • Chemical resistance
  • Dielectric and ferro-electric properties

Design

Ceramics are materials which are subject to particular design considerations, as they are not ductile and have a very high melting point. Preliminary powdering is necessary, prior to the consolidation of the material form at a high temperature. Various processes are available for this purpose: these include the liquid, plastic, or dry method.

Final Advanced Materials employs the liquid method for the formation of its basic ceramic products. The powdered raw material is dispersed in a solvent, together with a binder. This solid material in suspension forms the ceramic slip. It is then compacted in a tool in order to obtain the desired component. This step is described as extrusion. The extrudate must then be allowed to dry, before being fired at a high temperature. During sintering, the material grains bond together to consolidate the final product.

Technical Data of Cordierite Pressed Technical Ceramics

Property

Unit

Non-Porous Cordierite

Porous Cordierite

DIN EN 60 672 Identification

C410

C511

Composition

%

MgO•SiO2•Al

MgO•SiO2•Al

Density

g/cm3

> 2.1

> 1.9

Bulk Porosity

%

< 0.5

< 20

Colour 

yellow, brown, white

yellow, brown, white

Mechanical Characteristics at 20 °C

Hardness on Vickers’ Scale HV10 

MPa

-

-

Compressive Strength 

MPa

> 300

> 200

Flexural Strength 

MPa

> 60

> 25

Elastic Modulus

GPa

-

-

Thermal Characteristics

Max. Operating Temperature 

°C

1,000

1,200

Specific Warmth at 20 °C 

J K−1 kg−1

800-1,200

750-850

Thermal Conductivity at 100 °C 

W.m-1.K-1

1.5-2.5

1.3-1.8

Expansion Coefficient from 20 to 1,000 °C 

10-6/K-1

2-4.5

4-6

Electrical Characteristics

Electrical Resistivity

at 20 °C

Ω.m

> 1010

-

at 600 °C

> 103

> 103

Dielectric Strength

kV/mm

> 10

-



Physical variables included in this documentation are provided by way of indication only and do not, under any circumstances, constitute a contractual undertaking. Please contact our technical service if you require any additional information.

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