Category:
Ceramic
Material Type:
ceramic
Alternative Names:
Tags:
SIALON Ceramic
Ceramic
Basic Information
Composition & Structure
Composition:
Si₆₋ₓAlₓOₓN₈₋ₓ (β-SIALON)
Microstructure:
Elongated β-SIALON grains with intergranular glassy phase
Description
SIALON is a family of advanced engineering ceramics based on Si₃N₄ with aluminum and oxygen substitution. Combines thermal shock resistance and strength of silicon nitride with improved sinterability and oxidation resistance. Used for cutting tool inserts, wear components, thermocouple protection tubes. Machinable in green state and relatively easy to prepare compared to other engineering ceramics.
Mechanical Properties
Hardness:
1500 HV
Hardness (HV):
1500 HV
Hardness Category:
very hard
Tensile Strength:
700-900 MPa (flexural)
Physical Properties
Density:
3.24 g/cm³
Melting Point:
~1900 °C (decomposes)
Material Characteristics
Work Hardening:
No
Magnetic:
No
Corrosion Resistance:
excellent
Sectioning
Diamond wafering blade - medium grit / low concentration. Continuous coolant.
Mounting
Castable with epoxy or acrylic. Vacuum impregnation for porous grades.
Grinding
Diamond grinding discs (NOT SiC paper). 70μm diamond disc (planar), 30μm diamond on CERMESH metal mesh cloth (5 min).
Recommended Sequence:
Polishing
6μm diamond on TEXPAN with SIAMAT colloidal silica (5 min), 1μm diamond on GOLDPAD/ATLANTIS with SIAMAT (5 min), SIAMAT colloidal silica on TEXPAN (5 min).
Recommended Sequence:
Etching
Molten KOH preferentially dissolves glassy phase. Thermal etching at 1300-1500°C in N₂. Plasma etching (CF₄/O₂) as alternative.
Common Etchants:
Heat Treatment
Sintered at 1700-1800°C by gas pressure sintering or hot pressing. Not heat treated in service.
Relevant Standards
- ASTM C1161 (Flexural Strength)
- ASTM C1327 (Vickers Hardness)
Applications
- Cutting tool inserts
- Thermocouple protection tubes
- Welding pins
- Wear-resistant components
Typical Uses
- High-speed machining of cast iron and superalloys
- Molten metal handling
- Extrusion dies
- Bearing components