HPSiC
HPSiC is hot-pressed silicon carbide, densified under uniaxial pressure in graphite dies with boron/carbon (HP-BC) or alumina-based (HP-AL) aids, or HIP-densified, to give a fine-grain body at 3.2 g/cm³ with 450 GPa elastic modulus.
Reference datasheet — HPSiC 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 HP-BC condition
HPSiC tempers and conditions
HPSiC is supplied in 3 conditions, soft to hard. HP-BC is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot pressed with Al₂O₃/Y₂O₃ (liquid-phase) aids | Pick the liquid-phase Al₂O₃/Y₂O₃-aided hot pressed (LPS) grade for higher strength and toughness in wear-resistant structural parts, accepting 70 W/m·K and a 1400 °C limit. | 2,300 HV | 70 W/m·K | |||
HP-BCDefault Hot pressed with boron + carbon sintering aids | Choose this general-purpose hot pressed grade with boron and carbon aids for armor plate, seal rings and nozzles needing peak hardness, 125 W/m·K and 1600 °C service; machinability is only 3. | 2,600 HV | 125 W/m·K | |||
Hot isostatic pressed | Specify hot isostatic pressing for zero porosity and ultrafine grain — highest-strength armor, precision optical mirror blanks and post-densification of complex hot pressed shapes — at machinability 2. | 2,700 HV | 130 W/m·K |
What is HPSiC?
HPSiC is hot-pressed silicon carbide, densified under uniaxial pressure in graphite dies with boron/carbon (HP-BC) or alumina-based (HP-AL) aids, or HIP-densified, to give a fine-grain body at 3.2 g/cm³ with 450 GPa elastic modulus. Engineers specify it for armor and precision wear parts where maximum strength, hardness and stiffness outweigh cost, with 125 W/m·K conductivity, 1600 °C service and a 93 corrosion rating. Hot pressing restricts geometry to plates, blocks and discs and the process is slow and expensive; SSiC is the alternative for complex shapes and volume production. HPSiC has a density of 3.2 g/cm³ (0.116 lb/in³), lighter than 72% of ceramic grades. It melts at 2,730°C (4,946 °F). HPSiC has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 450 GPa (65.3 Msi).
What is HPSiC used for?
- ceramic armor
- ballistic tiles
- high-precision wear components
- optical mirror substrates
Advantages
- Good corrosion resistance — 93/100, better than 94% of ceramic grades
- Conducts heat well — 125 W/m·K (72.2 BTU/hr·ft·°F), better than 90% of ceramic grades
- Polishes to a fine finish — 92/100, better than 89% of ceramic grades
- High service temperature — 1,600°C (2,912 °F), better than 86% of ceramic grades
HPSiC properties
Typical room-temperature values for HPSiC-HP-BC; bars are the position among ceramic grades.
Physical3
HPSiC has a density of 3.2 g/cm³ (0.116 lb/in³), lighter than 72% of ceramic grades. It melts at 2,730°C (4,946 °F).
Mechanical12
HPSiC has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 450 GPa (65.3 Msi).
Thermal5
HPSiC is rated for continuous service to 1,600°C (2,912 °F). It conducts heat at 125 W/m·K (72.2 BTU/hr·ft·°F), better than 90% of ceramic grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
HPSiC has an electrical resistivity of 10 Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (93/100), better than 94% of ceramic grades.
Sustainability4
Producing a kilogram of HPSiC takes about 130 MJ of energy and emits 11 kg of CO₂ — more than 55% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
HPSiC's machinability is not recommended (3/100, worse than 95% of ceramic 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 ceramic family
Yield strength against density for every ceramic grade FabDigit runs. HPSiC is highlighted; hover a dot for its name, or open the interactive family chart.
Working with HPSiC
Is HPSiC easy to machine?
After sintering only diamond wheel grinding, ultrasonic or laser machining is possible; rough the green (pre-pressed) body with carbide tooling to reduce cost.
Can HPSiC be welded?
Not weldable; join by active-metal brazing (Ti/Ag-Cu), diffusion bonding or reaction bonding with a Si/C interlayer.
Can HPSiC be formed, bent or molded?
Uniaxial hot pressing in graphite dies yields only simple shapes such as plates, blocks and discs; complex geometry must be pressed or isostatically formed first and then densified by HIP.
HPSiC 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 |
|---|---|---|
| Bboron sintering aid (HP-BC type), usually added as B₄C | 0.2 – 1 | 0.5 |
| C (free)free carbon, removes surface SiO₂ | 0.3 – 2 | 1 |
| Al2O3only in liquid-phase HP-AL type, usually with Y₂O₃ | 0 – 3 | 0 |
| Y2O3only in liquid-phase HP-AL type | 0 – 2 | 0 |
| Feimpurity introduced by ball milling | 0 – 0.1 | 0.03 |
| SiCα-SiC (6H) main phase, fine grain 1–5 µm | ≥ 97 (balance) |
What surface finishes work on HPSiC?
Can be precision lapped and polished to Ra <0.02 µm (optical parts are polished after a Si cladding layer is applied); a CVD-SiC coating can be used to seal the surface and improve surface integrity.
How much does HPSiC cost?
HPSiC is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
HPSiC — frequently asked
What is HPSiC used for?
HPSiC is typically used for ceramic armor, ballistic tiles, high-precision wear components and optical mirror substrates. In short: highest-density SiC route; simple shapes only; armor-grade fine grain.
What is the tensile strength of HPSiC?
HPSiC has a typical tensile strength of 350 MPa (50.8 ksi) — stronger than 71% of ceramic grades. Strength varies by condition: see the 3 listed tempers.
Is HPSiC easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 95% of ceramic grades). After sintering only diamond wheel grinding, ultrasonic or laser machining is possible; rough the green (pre-pressed) body with carbide tooling to reduce cost.
Can HPSiC be welded?
Not weldable; join by active-metal brazing (Ti/Ag-Cu), diffusion bonding or reaction bonding with a Si/C interlayer.
What surface finishes work on HPSiC?
Can be precision lapped and polished to Ra <0.02 µm (optical parts are polished after a Si cladding layer is applied); a CVD-SiC coating can be used to seal the surface and improve surface integrity.
Can HPSiC be formed, bent or molded?
Uniaxial hot pressing in graphite dies yields only simple shapes such as plates, blocks and discs; complex geometry must be pressed or isostatically formed first and then densified by HIP.
What is the maximum service temperature of HPSiC?
HPSiC is rated for continuous use to about 1,600°C (2,912 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does HPSiC cost?
HPSiC is a high-cost ceramic ($$$$), 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 Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- Silicon Carbide Material Properties (hot-pressed / sintered grades) — CoorsTek (2023)
- Fine Ceramics Technical Data — SiC — Kyocera (2022)
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.