HPSiC HIP (Hot isostatic pressed)
Print state
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.
Values for the HIP condition
Other HPSiC tempers and conditions
HPSiC is listed in 3 conditions; see the grade overview at HPSiC.
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 |
HIPThis page 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 HIP?
HPSiC HIP is HPSiC in the HIP condition — 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. HPSiC HIP has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 460 GPa (66.7 Msi). HPSiC HIP has a density of 3.21 g/cm³ (0.116 lb/in³), lighter than 71% of ceramic grades. It melts at 2,730°C (4,946 °F). HP-BC is the default condition FabDigit quotes; HIP is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 96/100, better than 99% of ceramic grades
- Good corrosion resistance — 93/100, better than 94% of ceramic grades
- Conducts heat well — 130 W/m·K (75.1 BTU/hr·ft·°F), better than 91% of ceramic grades
- High service temperature — 1,650°C (3,002 °F), better than 88% of ceramic grades
- Stiff — 460 GPa (66.7 Msi), better than 75% of ceramic grades
HPSiC HIP properties
Typical room-temperature values for HPSiC HIP; 11 are specific to this condition. Other listed values are HPSiC reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
HPSiC HIP has a density of 3.21 g/cm³ (0.116 lb/in³), lighter than 71% of ceramic grades. It melts at 2,730°C (4,946 °F).
Mechanical12
HPSiC HIP has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 460 GPa (66.7 Msi).
Thermal5
HPSiC HIP is rated for continuous service to 1,650°C (3,002 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), better than 91% of ceramic grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
HPSiC HIP 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 HIP 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 HIP's machinability is not recommended (2/100, worse than 100% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HPSiC HIP
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.
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.
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) | — |
HPSiC HIP — frequently asked
What is HPSiC HIP used for?
HPSiC HIP 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 HIP?
HPSiC HIP 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 HIP easy to machine?
Not especially — machinability is rated not recommended (2/100, worse than 100% 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 HIP 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 HIP?
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 HIP 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 HIP?
HPSiC HIP is rated for continuous use to about 1,650°C (3,002 °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)
- 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.