NON oxide ceramics
SILICON Nitride (Si3N4)
This material offers a hitherto unattainable combination of outstanding properties:
- Extremely high strength
- Very high toughness
- Excellent wear resistance
- Very low thermal expansion
- High thermal conductivity
- Outstanding thermal shock resistance
- Very good chemical resistance
The sintering process of silicon nitride has to take place by a very high mechanical pressure in a controlled atmosphere. Depending on the process the result is:
- sintered silicon nitride (SSN)
- gas pressure sintered silicon nitride (GPSSN) or
- hot-pressed silicon nitride (HPSN)
In comparison reaction bonded nitride (RBSN) - starting substance Si-powder - is nitrided shrink free in a specifically set N2-atmosphere
SILICON ALUMINIUM OXYNITRIDE (SIALON)
It is mainly based on compounds or solid solutions of a four-component system silicon - aluminium - oxygen - nitrogen.
On account of its fracture toughness it is often used for
- Cutting tools. Due to the low wettability through non ferrous metals, SIALON is a standard material for
- Thermocouple protection tubes.
ALUMINIUM NITRIDE (ALN)
An irresistible material due to its extraordinary high thermal conductivity: up to 180 Wm-1 K-1. Moreover the combination of properties speak for themselves:
- Best thermal conductivity
- High electrical insulation
- Thermal expansion similar to Si (‹Al2O3)
- Inert behaviour towards melting of the III-V-compounds
- High rigidity.
ALN is especially suitable as
- Substrate for semi-conducting components and
- Power electronic modules.