SIGRASIC<sup>®</sup>

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$SIGRASIC combines a high hardness with a good fracture toughness.$

SIGRASIC obtains its outstanding properties from the combination of carbon fiber with a silicon carbide (SiC) matrix. This leads to a composite material (C/SiC) with high hardness but also good fracture toughness.

SIGRASIC is manufactured by infiltrating porous carbon fiber reinforced carbon bodies with liquid silicon. The specific properties of SIGRASIC materials can be tailored to your needs. This is achieved by adjusting the production parameters as well as by the amount and type of the carbon fibers. Currently, milled fibres (SIGRASIC MF), short fibres (SIGRASIC SF) and long fibres (SIGRASIC LF) are available. Even complex component geometries can be produced by near-net-shape production.

High hardness & fracture toughness
High chemical resistance
Near-net-shape production with the possibility of joining components during manufacturing
Well suited for high temperature applications
High thermal shock resistance compared to monolithic ceramics

Composite material made of SiC matrix and milled carbon fibers

SIGRASIC MF is particularly suitable for applications requiring high wear resistance, high mechanical strength and low weight. In addition to its high thermal conductivity, this material exhibits the typical brittle fracture behavior of a ceramic. A remarkable success is the use of SIGRASIC MF in NASA's "Mission to Jupiter" (JUNO). For this purpose, SIGRASIC MF was used as material for the instrument panels of the satellite.

Composite material made of SiC matrix and short carbon fibers

Ductile materials are obtained by incorporating short carbon fibers into a ceramic matrix. This material is characterized by a pseudo-plastic behavior under mechanical stress. The amount of carbon fibers in the ceramic matrix allows tailoring a wide range of mechanical and physical properties to your requirements. SIGRASIC SF is established in the automotive industry for serial-produced C/SiC brake disks.

Composite material made of SiC matrix and long carbon fibers

SIGRASIC LF is especially suitable for applications under the highest mechanical stress. By incorporating long or continuous carbon fibers into a ceramic matrix, materials which are more dominated by the fiber properties than by the properties of the ceramic matrix are obtained. This material is characterized by a low density with high elongation at break and high strength. Today, SIGRASIC LF is mainly used in the field of ceramic C/SiC clutch disks for high-performance vehicles.

Property	Unit	SIGRASIC MF	SIGRASIC SF	SIGRASIC LF
Density	g/cm³	2.7-3.0	2.1-2.8	1.8-2.2
Young's modulus	GPa	150-330	30-60	50-80
Flexural strength	MPa	130-350	50-90	150-230
Bending strength	%	0.01-0.05	0.3-0.5	0.4-0.6
Thermal conductivity 20°C)	W/(mK)	110-160	20-60	13-20
Coefficient of thermal expansion (RT/200°C)	μm/(mK)	2.9-3.5	1.8-2.3	0.3-0.5
Max. Temperature resistance*	°C	1400	1400	1400