SiC/SiC
also Nicalon/SiC, Hi-Nicalon Type S/SiC
SiC/SiC is a continuous SiC-fiber reinforced SiC-matrix composite (Nicalon, Hi-Nicalon Type S or SA3 fibers with a BN interphase) densified by CVI, melt infiltration, PIP or NITE processing.
Reference datasheet — SiC/SiC is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the CVI condition
SiC/SiC grades and fills
SiC/SiC is supplied in 7 conditions, soft to hard. CVI is the default FabDigit quotes; the values on this page are for it.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Nicalon CG fiber reinforcement | Specify this first-generation, lowest-cost fibre only for moderate-temperature or short-life parts; its oxygen-containing, non-stoichiometric structure creeps and loses mass above 1100 °C. | 80 | 250 | 0.4 | |
Hi-Nicalon Type S fiber reinforcement | Pick the near-stoichiometric, low-oxygen fibre as the default reinforcement for 1300 °C-class engine hot-section parts where creep resistance and 320 MPa strength are required. | 120 | 320 | 0.6 | |
Tyranno SA3 / Sylramic fiber reinforcement | Choose the highly crystalline fibre with a little sintering aid for the highest temperatures and nuclear service, giving 30 W/m·K and best creep resistance; it is more brittle and limits weaving radius. | 140 | 300 | 0.4 | |
Nano-infiltration & transient eutectic-phase sintering | Choose nano-infiltration and transient eutectic-phase sintering for nuclear fuel cladding and fusion first walls needing near-theoretical density, 45 W/m·K and gas tightness; hot pressing limits shapes. | 200 | 400 | 0.4 | |
Polymer infiltration & pyrolysis matrix | Use polymer infiltration and pyrolysis for large, complex, cost-sensitive exhaust and secondary-load structures; the porous matrix gives only 8 W/m·K and 1200 °C capability. | 250 | 0.7 | ||
CVIDefault Chemical vapor infiltration matrix | Choose chemical vapour infiltration on a 2D/3D woven preform for aero-engine hot sections needing the highest matrix purity and temperature capability; accept 10–15 % residual porosity and long deposition cycles. | 300 | 0.6 | ||
Melt-infiltrated | Pick melt infiltration for turbine shrouds and combustor liners needing near-full density, 28 W/m·K conduction and good interlaminar strength; free silicon limits use to about 1315 °C. | 320 | 0.45 |
Supply forms, finishes and certifications
Ways SiC/SiC is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EBC | EBC-coated | Surface finish |
What is SiC/SiC?
SiC/SiC is a continuous SiC-fiber reinforced SiC-matrix composite (Nicalon, Hi-Nicalon Type S or SA3 fibers with a BN interphase) densified by CVI, melt infiltration, PIP or NITE processing. At 2.5 g/cm³ it gives 300 MPa tensile strength, 230 GPa modulus, 0.6% elongation and 15 W/m·K, and retains strength above 1200 °C with rated service to 1350 °C — hence its use in the hottest gas-turbine sections. Machinability is rated 4, so hardware is woven to near-net shape and only diamond- or beam-finished. Densification runs for weeks and steam service requires an environmental barrier coating; C/SiC is cheaper where oxidising life is short. SiC/SiC has a density of 2.5 g/cm³ (0.0903 lb/in³), heavier than 81% of composite grades. SiC/SiC has a tensile strength of 300 MPa (43.5 ksi), stronger than 53% of composite grades. Elongation at break is 0.6% and the elastic modulus is 230 GPa (33.4 Msi).
What is SiC/SiC used for?
- turbine shrouds and combustor liners
- nuclear cladding research
- hypersonic leading edges
- rocket combustion chambers
- industrial burner components
Advantages
- High service temperature — 1,350°C (2,462 °F), better than 98% of composite grades
- Good UV / weathering resistance — 100/100, better than 93% of composite grades
- Polishes to a fine finish — 55/100, better than 83% of composite grades
- Stiff — 230 GPa (33.4 Msi), better than 82% of composite grades
- Tough — resists crack growth — 25 MPa·√m (22.8 ksi·√in), better than 80% of composite grades
Limitations
- High embodied carbon — 110 kg CO₂/kg, worse than 100% of composite grades
- Difficult to machine — 4/100, worse than 99% of composite grades
- Limited ductility — 0.6%, worse than 88% of composite grades
- Heavy — 2.5 g/cm³ (0.0903 lb/in³), worse than 81% of composite grades
SiC/SiC properties
Typical room-temperature values for SiC/SiC-CVI; bars are the position among composite grades.
Physical1
SiC/SiC has a density of 2.5 g/cm³ (0.0903 lb/in³), heavier than 81% of composite grades.
Mechanical12
SiC/SiC has a tensile strength of 300 MPa (43.5 ksi), stronger than 53% of composite grades. Elongation at break is 0.6% and the elastic modulus is 230 GPa (33.4 Msi).
Thermal6
SiC/SiC is rated for continuous service to 1,350°C (2,462 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), better than 77% of composite grades. Thermal expansion is 4.3 µm/m·K (2.39 µin/in·°F).
Electrical1
SiC/SiC has an electrical resistivity of 0.1 Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 77% of composite grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of SiC/SiC takes about 1,500 MJ of energy and emits 110 kg of CO₂ — more than 100% of composite grades. Typical recycled content is 0%.
Manufacturability2
SiC/SiC's machinability is not recommended (4/100, worse than 99% of composite grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. SiC/SiC is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SiC/SiC
Is SiC/SiC easy to machine?
Diamond grinding, ultrasonic, laser or waterjet cutting only; cutting tears the fibers and damages the interphase, so produce holes and contours net-shape at the preform stage.
Can SiC/SiC be welded?
Not weldable. Use Si-based or MAX-phase brazing, glass-ceramic or precursor-conversion joining, or CMC bolts with compliant metal bushings to absorb thermal mismatch.
Can SiC/SiC be formed, bent or molded?
Weave or lay up the SiC-fiber preform to the part contour and deposit the BN interphase, then densify with multiple CVI/PIP cycles or Si melt infiltration; cycle times run to several weeks and tooling must survive above 1000 °C.
SiC/SiC 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 |
|---|---|---|
| SiC fiber (Nicalon/Hi-Nicalon Type S/TyrVolume fraction; 2D/3D woven or laid up | 30 – 45 | 38 |
| BN or PyC interphase0.3-1 um interphase controlling fiber debonding | 1 – 4 | 2 |
| free SiOnly in MI melt infiltration; limits maximum use temperature | 0 – 15 | 0 |
| porosityCVI 10–15% MI/NITE <3% | 1 – 15 | 10 |
| SiC matrixdensified by CVI/PIP/MI | ≥ 40 (balance) |
What surface finishes work on SiC/SiC?
Seal the surface with a CVI layer, then plasma-spray a Si bond coat plus an ytterbium/yttrium silicate EBC. No plating or anodising; inspect by CT and ultrasonic porosity mapping with infrared thermography.
Equivalent designations
Standards and trade names that resolve to SiC/SiC in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Nicalon/SiCHi-Nicalon Type S/SiC
How much does SiC/SiC cost?
SiC/SiC is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SiC/SiC — frequently asked
What is SiC/SiC used for?
SiC/SiC is typically used for turbine shrouds and combustor liners, nuclear cladding research, hypersonic leading edges, rocket combustion chambers and industrial burner components. In short: highest-strength CMC here; strength retained above 1200 °C; turbine hot-section grade.
What is the tensile strength of SiC/SiC?
SiC/SiC has a typical tensile strength of 300 MPa (43.5 ksi) — stronger than 53% of composite grades. Strength varies by condition: see the 7 listed tempers.
Is SiC/SiC easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 99% of composite grades). Diamond grinding, ultrasonic, laser or waterjet cutting only; cutting tears the fibers and damages the interphase, so produce holes and contours net-shape at the preform stage.
Can SiC/SiC be welded?
Not weldable. Use Si-based or MAX-phase brazing, glass-ceramic or precursor-conversion joining, or CMC bolts with compliant metal bushings to absorb thermal mismatch.
What surface finishes work on SiC/SiC?
Seal the surface with a CVI layer, then plasma-spray a Si bond coat plus an ytterbium/yttrium silicate EBC. No plating or anodising; inspect by CT and ultrasonic porosity mapping with infrared thermography.
Can SiC/SiC be formed, bent or molded?
Weave or lay up the SiC-fiber preform to the part contour and deposit the BN interphase, then densify with multiple CVI/PIP cycles or Si melt infiltration; cycle times run to several weeks and tooling must survive above 1000 °C.
What is the maximum service temperature of SiC/SiC?
SiC/SiC is rated for continuous use to about 1,350°C (2,462 °F), and briefly to 1,600°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SiC/SiC CVI and SiC/SiC NITE?
CVI is the default condition — choose chemical vapour infiltration on a 2D/3D woven preform for aero-engine hot sections needing the highest matrix purity and temperature capability; accept 10–15 % residual porosity and long deposition cycles. NITE: choose nano-infiltration and transient eutectic-phase sintering for nuclear fuel cladding and fusion first walls needing near-theoretical density, 45 W/m·K and gas tightness; hot pressing limits shapes.
How much does SiC/SiC cost?
SiC/SiC is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol.21: Composites — Ceramic Matrix Composites — ASM International (2001)
- ASTM C1275 / C1292 / C1341 — Tensile, Shear and Flexural Testing of CMCs — ASTM International (2018)
- NASA Glenn CMC property compilations for CVI/MI SiC/SiC — NASA (2015)
- Nicalon / Hi-Nicalon / Hi-Nicalon Type S fiber data — NGS Advanced Fibers (2020)
- Tyranno SA3 SiC fiber data — Ube Industries (2019)
- Handbook of SiC/SiC Composites for Nuclear Applications (NITE / ) — ORNL / IAEA (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.