RBSiC/SiSiC SISIC-C
Grade
SISIC-C = graphite-loaded self-lubricating SiSiC for seal faces
Use for dry-running or poorly lubricated mechanical seals and bearings where the dispersed graphite lowers friction and blister risk.
Values for the SISIC-C condition
Other RBSiC/SiSiC tempers and conditions
RBSiC/SiSiC is listed in 4 conditions; see the grade overview at RBSiC/SiSiC.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SISIC-STDDefault standard reaction-bonded SiSiC (≈88–90 % SiC, 10–12 % free Si) | Default choice for nozzles, wear liners, heat-exchanger tubes and general near-net-shape SiSiC parts up to 1350 °C. | — | 200 | — | 2,300 HV | 130 W/m·K |
fine-grain, low free-silicon high-strength SiSiC (≥92 % SiC) | Pick when maximum bend strength, hardness and wear life are needed — seal faces, bearings, precision optics substrates, ballistic tiles. | — | 250 | — | 2,500 HV | 150 W/m·K |
SISIC-CThis page Graphite-loaded self-lubricating SiSiC for seal faces | Use for dry-running or poorly lubricated mechanical seals and bearings where the dispersed graphite lowers friction and blister risk. | — | — | — | 1,800 HV | 110 W/m·K |
coarse-grain kiln-furniture / thermal grade (beams, rollers, plates) | Cheapest large-section SiSiC for kiln beams, roller-hearth rolls, saggars and burner tubes where thermal shock and creep matter more than strength. | — | — | — | 2,100 HV | 110 W/m·K |
What is RBSiC/SiSiC SISIC-C?
RBSiC/SiSiC SISIC-C is RBSiC/SiSiC in the SISIC-C grade — use for dry-running or poorly lubricated mechanical seals and bearings where the dispersed graphite lowers friction and blister risk. RBSiC/SiSiC SISIC-C has a tensile strength of 200 MPa (29 ksi), stronger than 60% of ceramic grades. Elongation at break is 0% and the elastic modulus is 320 GPa (46.4 Msi). RBSiC/SiSiC SISIC-C has a density of 2.9 g/cm³ (0.105 lb/in³), lighter than 76% of ceramic grades. It melts at 1,410°C (2,570 °F). SISIC-STD is the default condition FabDigit quotes; SISIC-C is available on request or by drawing note.
Advantages
- Conducts heat well — 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades
- High service temperature — 1,300°C (2,372 °F), better than 77% of ceramic grades
- Good corrosion resistance — 88/100, better than 77% of ceramic grades
- Lightweight — 2.9 g/cm³ (0.105 lb/in³), better than 76% of ceramic grades
RBSiC/SiSiC SISIC-C properties
Typical room-temperature values for RBSiC/SiSiC SISIC-C; 10 are specific to this condition. Other listed values are RBSiC/SiSiC reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
RBSiC/SiSiC SISIC-C has a density of 2.9 g/cm³ (0.105 lb/in³), lighter than 76% of ceramic grades. It melts at 1,410°C (2,570 °F).
Mechanical13
RBSiC/SiSiC SISIC-C has a tensile strength of 200 MPa (29 ksi), stronger than 60% of ceramic grades. Elongation at break is 0% and the elastic modulus is 320 GPa (46.4 Msi).
Thermal5
RBSiC/SiSiC SISIC-C is rated for continuous service to 1,300°C (2,372 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades. Thermal expansion is 4.3 µm/m·K (2.39 µin/in·°F).
Electrical2
RBSiC/SiSiC SISIC-C has an electrical resistivity of 0.001 Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (88/100), better than 77% of ceramic grades.
Sustainability4
Producing a kilogram of RBSiC/SiSiC SISIC-C takes about 105 MJ of energy and emits 7.5 kg of CO₂ — less than 54% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
RBSiC/SiSiC SISIC-C's machinability is not recommended (6/100, better than 61% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with RBSiC/SiSiC SISIC-C
Is RBSiC/SiSiC easy to machine?
All shaping is done green (turning, milling, drilling of the porous preform); after siliconising only diamond grinding, lapping, ultrasonic or EDM (the material is conductive) is possible.
Can RBSiC/SiSiC be welded?
Not weldable; joints are made by silicon brazing during infiltration, glass/oxide sealing or by mechanical/adhesive assembly with compliant gaskets.
Can RBSiC/SiSiC be formed, bent or molded?
Preforms are slip-cast, pressure-cast, extruded, isostatically pressed or 3D-printed and then infiltrated with molten Si at 1450–1600 °C in vacuum/argon with essentially zero shrinkage, which allows very large and complex parts.
What surface finishes work on RBSiC/SiSiC?
Excess surface silicon is grit-blasted or ground off; seal and bearing faces are diamond-lapped to <0.1 µm Ra, and a thermally grown SiO₂ film provides the oxidation protection — no plating or painting is used.
RBSiC/SiSiC chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SiCprimary α-SiC grains plus secondary β-SiC formed by the Si + C reaction | 85 – 94 | 89 |
| Cresidual free carbon; intentionally higher (up to ~5 %) in graphite-loaded seal grades | 0 – 1 | 0.2 |
| Fe+Al+Ca oxidesraw-material impurities | 0 – 0.5 | 0.2 |
| Sifree metallic silicon filling the former pore network | ≥ 6 (balance) | — |
RBSiC/SiSiC SISIC-C — frequently asked
What is RBSiC/SiSiC SISIC-C used for?
RBSiC/SiSiC SISIC-C is typically used for kiln furniture, burner nozzles, mechanical seal faces, semiconductor process components and heat exchanger tubes. In short: cheapest near-net-shape SiC; zero-shrinkage large parts; free silicon limits temperature.
What is the tensile strength of RBSiC/SiSiC SISIC-C?
RBSiC/SiSiC SISIC-C has a typical tensile strength of 200 MPa (29 ksi) — stronger than 60% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is RBSiC/SiSiC SISIC-C easy to machine?
Not especially — machinability is rated not recommended (6/100, better than 61% of ceramic grades). All shaping is done green (turning, milling, drilling of the porous preform); after siliconising only diamond grinding, lapping, ultrasonic or EDM (the material is conductive) is possible.
Can RBSiC/SiSiC SISIC-C be welded?
Not weldable; joints are made by silicon brazing during infiltration, glass/oxide sealing or by mechanical/adhesive assembly with compliant gaskets.
What surface finishes work on RBSiC/SiSiC SISIC-C?
Excess surface silicon is grit-blasted or ground off; seal and bearing faces are diamond-lapped to <0.1 µm Ra, and a thermally grown SiO₂ film provides the oxidation protection — no plating or painting is used.
Can RBSiC/SiSiC SISIC-C be formed, bent or molded?
Preforms are slip-cast, pressure-cast, extruded, isostatically pressed or 3D-printed and then infiltrated with molten Si at 1450–1600 °C in vacuum/argon with essentially zero shrinkage, which allows very large and complex parts.
What is the maximum service temperature of RBSiC/SiSiC SISIC-C?
RBSiC/SiSiC SISIC-C is rated for continuous use to about 1,300°C (2,372 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASM Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- Reaction-bonded silicon carbide (SiSiC) component datasheets — Saint-Gobain / CoorsTek / Kyocera / 3M Technical Ceramics (2023)
- Technical ceramics property tables — non-oxide carbides — Ceramic Industry / Matmatch compiled producer data (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.