ZrB2-SiC ZS20-HP
Reinforced grade · default condition
ZS20-HP = zrB2 + 20 vol% SiC, hot pressed
The industry/NASA baseline UHTC: best balance of strength, oxidation resistance and conductivity for hypersonic leading edges.
Values for the ZS20-HP condition
Other ZrB2-SiC grades and fills
ZrB2-SiC is listed in 7 conditions; see the grade overview at ZrB2-SiC.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Cf/ZrB2-SiC | Choose for large, damage-tolerant hot structures where pseudo-ductile, non-catastrophic failure is mandatory. | — | 180 | 0.5 | — |
ZrB2-SiC with graphite/carbon-black addition | Select where thermal-shock resistance and machinability outrank absolute bend strength (nozzles, electrodes, crucibles). | — | 190 | 0.1 | — |
ZrB2 + 10 vol% SiC, hot pressed | Choose when maximum thermal/electrical conductivity and stiffness matter more than oxidation life above 1500 °C. | — | 280 | 0.12 | — |
ZrB2-SiC with 10–20 vol% MoSi2 | Use when long isothermal oxidation life at 1400–1600 °C is the driver; MoSi2 also aids pressureless densification. | — | 300 | 0.14 | — |
ZrB2 + 30 vol% SiC, hot pressed | Pick when oxidation life and room-temperature strength dominate and lower conductivity is acceptable. | — | 350 | 0.16 | — |
SiC-whisker / chopped-fibre toughened ZrB2-SiC | Pick when a ~30 % gain in fracture toughness and crack-deflection behaviour is needed in a monolithic-like body. | — | 380 | 0.18 | — |
ZS20-HPDefaultThis page ZrB2 + 20 vol% SiC, hot pressed | The industry/NASA baseline UHTC: best balance of strength, oxidation resistance and conductivity for hypersonic leading edges. | — | — | — | — |
What is ZrB2-SiC ZS20-HP?
ZrB2-SiC ZS20-HP is ZrB2-SiC in the ZS20-HP grade — the industry/NASA baseline UHTC: best balance of strength, oxidation resistance and conductivity for hypersonic leading edges. ZrB2-SiC ZS20-HP has a tensile strength of 320 MPa (46.4 ksi), stronger than 57% of composite grades. The elastic modulus is 490 GPa (71.1 Msi). ZrB2-SiC ZS20-HP has a density of 5.5 g/cm³ (0.199 lb/in³), heavier than 94% of composite grades.
Advantages
- High service temperature — 1,600°C (2,912 °F), better than 100% of composite grades
- Stiff — 490 GPa (71.1 Msi), better than 97% of composite grades
- Polishes to a fine finish — 80/100, better than 97% of composite grades
- Good UV / weathering resistance — 100/100, better than 93% of composite grades
- Conducts heat well — 78 W/m·K (45.1 BTU/hr·ft·°F), better than 88% of composite grades
Limitations
- Heavy — 5.5 g/cm³ (0.199 lb/in³), worse than 94% of composite grades
- Difficult to machine — 8/100, worse than 94% of composite grades
ZrB2-SiC ZS20-HP properties
Typical room-temperature values for ZrB2-SiC ZS20-HP; 10 are specific to this condition. Other listed values are ZrB2-SiC reference data and may not represent this condition. Bars are the position among composite grades.
Physical1
ZrB2-SiC ZS20-HP has a density of 5.5 g/cm³ (0.199 lb/in³), heavier than 94% of composite grades.
Mechanical9
ZrB2-SiC ZS20-HP has a tensile strength of 320 MPa (46.4 ksi), stronger than 57% of composite grades. The elastic modulus is 490 GPa (71.1 Msi).
Thermal6
ZrB2-SiC ZS20-HP is rated for continuous service to 1,600°C (2,912 °F). It conducts heat at 78 W/m·K (45.1 BTU/hr·ft·°F), better than 88% of composite grades. Thermal expansion is 6 µm/m·K (3.33 µin/in·°F).
Electrical2
ZrB2-SiC ZS20-HP has an electrical resistivity of 1.5×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 55% of composite grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of ZrB2-SiC ZS20-HP takes about 300 MJ of energy and emits 22 kg of CO₂ — more than 68% of composite grades. Typical recycled content is 0%.
Manufacturability2
ZrB2-SiC ZS20-HP's machinability is not recommended (8/100, worse than 94% of composite grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZrB2-SiC ZS20-HP
Is ZrB2-SiC easy to machine?
Diamond grinding/lapping only for conventional cutting; because ZrB2-SiC is electrically conductive it can be wire- and sinker-EDM machined, which is the practical route for complex leading-edge geometries.
Can ZrB2-SiC be welded?
Not weldable; joining is by active brazing (Ti/Zr-bearing filler), reaction bonding, or mechanical/co-sintered attachment to metallic or C/C substructures.
Can ZrB2-SiC be formed, bent or molded?
Shaped by hot pressing, spark plasma sintering, or pressureless sintering (with B4C/C/MoSi2 aids) from green bodies made by cold pressing, slip/tape casting or additive-manufactured preforms; near-net shaping is preferred because post-sinter machining is very costly.
What surface finishes work on ZrB2-SiC?
Diamond lapping/polishing to sub-µm Ra; oxidation-protective or emissivity coatings (SiC CVD, silicide, HfO2-based) are often applied for repeated re-entry cycles.
ZrB2-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 |
|---|---|---|
| SiC20 vol% SiC ≈ 11.6 wt% for the baseline ZS20 grade | 5 – 20 | 11.6 |
| B4Coptional sintering aid / oxide scavenger | 0 – 2 | 0.5 |
| Cfree carbon aid; removes ZrO2/B2O3 surface oxides | 0 – 2 | 0.3 |
| ZrO2 + B2O3 impuritiesresidual powder oxides | 0 – 1.5 | 0.5 |
| ZrB2matrix phase, ~88 wt% in ZS20 | balance | — |
ZrB2-SiC ZS20-HP — frequently asked
What is ZrB2-SiC ZS20-HP used for?
ZrB2-SiC ZS20-HP is typically used for hypersonic vehicle nose caps and leading edges, rocket nozzle inserts, plasma-facing components and re-entry thermal protection. In short: 1600 °C UHTC composite; electrically conductive, EDM-machinable; stiffest composite in family.
What is the tensile strength of ZrB2-SiC ZS20-HP?
ZrB2-SiC ZS20-HP has a typical tensile strength of 320 MPa (46.4 ksi) — stronger than 57% of composite grades. Strength varies by condition: see the 7 listed tempers.
Is ZrB2-SiC ZS20-HP easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 94% of composite grades). Diamond grinding/lapping only for conventional cutting; because ZrB2-SiC is electrically conductive it can be wire- and sinker-EDM machined, which is the practical route for complex leading-edge geometries.
Can ZrB2-SiC ZS20-HP be welded?
Not weldable; joining is by active brazing (Ti/Zr-bearing filler), reaction bonding, or mechanical/co-sintered attachment to metallic or C/C substructures.
What surface finishes work on ZrB2-SiC ZS20-HP?
Diamond lapping/polishing to sub-µm Ra; oxidation-protective or emissivity coatings (SiC CVD, silicide, HfO2-based) are often applied for repeated re-entry cycles.
Can ZrB2-SiC ZS20-HP be formed, bent or molded?
Shaped by hot pressing, spark plasma sintering, or pressureless sintering (with B4C/C/MoSi2 aids) from green bodies made by cold pressing, slip/tape casting or additive-manufactured preforms; near-net shaping is preferred because post-sinter machining is very costly.
What is the maximum service temperature of ZrB2-SiC ZS20-HP?
ZrB2-SiC ZS20-HP is rated for continuous use to about 1,600°C (2,912 °F), and briefly to 2,200°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications — Wiley/ACerS (2014)
- Journal of the American Ceramic Society — ZrB2-SiC property compilations (Fahrenholtz, Hilmas et al.) — ACerS (2012)
- ASM Engineered Materials Handbook Vol.4 — Ceramics and Glasses — ASM International (1991)
- Specialty UHTC hot-pressed ZrB2-SiC billet data (research/industrial suppliers) — various (2023)
- ZrB2 ZrB2-SiC / (2025)
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.