Category:
Ceramic
Material Type:
ceramic
Alternative Names:
Tags:
SiSiC (Reaction-Bonded Silicon Carbide)
Ceramic
Basic Information
Composition & Structure
Composition:
SiC grains bonded by free silicon (~8-15% free Si)
Microstructure:
Angular SiC grains in a continuous free-silicon matrix
Description
Reaction-bonded silicon carbide (SiSiC) is produced by infiltrating molten silicon into a porous SiC/carbon preform. Distinct from sintered SiC — contains free silicon phase. Used in pump seals, kiln furniture, heat exchangers, burner nozzles. Preparation must account for the two-phase microstructure (very hard SiC + softer free silicon).
Mechanical Properties
Hardness:
2200 HV (SiC), ~1100 HV (Si)
Hardness Category:
very hard
Tensile Strength:
250-400 MPa (flexural)
Physical Properties
Density:
3.05-3.15 g/cm³
Melting Point:
~2700 °C (SiC), Si melts 1414 °C
Material Characteristics
Work Hardening:
No
Magnetic:
No
Corrosion Resistance:
excellent
Sectioning
Diamond wafering blade - medium grit / low concentration. Diamond tooling required.
Mounting
Castable with epoxy or acrylic.
Grinding
Diamond grinding discs (NOT SiC paper — material IS SiC). 70μm diamond disc (planar), 30μm diamond on CERMESH (5 min).
Recommended Sequence:
Polishing
6μm diamond on TEXPAN with SIAMAT (5 min), 1μm diamond on GOLDPAD/ATLANTIS with SIAMAT (5 min), SIAMAT colloidal silica on TEXPAN (5 min).
Recommended Sequence:
Etching
Best examined as-polished — SiC (dark) and Si (bright) clearly visible in BF. DIC enhances contrast. Murakami's reagent (KOH + K₃Fe(CN)₆) selectively attacks SiC grains. Dilute HF (10%) etches the free silicon phase. Molten KOH at elevated temperature attacks both phases.
Common Etchants:
Heat Treatment
Not heat treated. Manufactured by silicon infiltration at ~1500-1600°C.
Applicable Standards
- ASTM C1161
- ASTM C1327
- DIN EN 60672-3
Applications
- Pump seals and bearings
- Kiln furniture
- Heat exchangers
- Burner nozzles
Typical Uses
- Chemical pump mechanical seals
- Roller kilns
- Radiant heating tubes
- Ballistic armor
- Semiconductor processing