TaC SPS
Grade
SPS = spark-plasma-sintered fine-grain TaC
Pick when maximum strength, hardness and toughness are needed: fast SPS cycles keep grain size a few µm and close residual porosity.
Values for the SPS condition
Other TaC tempers and conditions
TaC is listed in 3 conditions; see the grade overview at TaC.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Pressureless sintered TaC | Lower-cost route for complex shapes; residual porosity and aid phases cut strength, hardness and conductivity. | — | — | — | 1,450 HV | 16 W/m·K |
HPDefault Hot-pressed sintered TaC ceramic | Standard route for bulk TaC parts and UHTC test pieces: uniaxial hot pressing at 1900–2100 °C gives near-full density with moderate grain growth. | — | — | — | 1,700 HV | 22 W/m·K |
SPSThis page Spark-plasma-sintered fine-grain TaC | Pick when maximum strength, hardness and toughness are needed: fast SPS cycles keep grain size a few µm and close residual porosity. | — | — | — | 1,900 HV | 25 W/m·K |
What is TaC SPS?
TaC SPS is TaC in the SPS grade — pick when maximum strength, hardness and toughness are needed: fast SPS cycles keep grain size a few µm and close residual porosity. The elastic modulus is 540 GPa (78.3 Msi). TaC SPS has a density of 14.55 g/cm³ (0.526 lb/in³), heavier than 92% of ceramic grades. It melts at 3,880°C (7,016 °F). HP is the default condition FabDigit quotes; SPS is available on request or by drawing note.
Advantages
- High service temperature — 2,400°C (4,352 °F), better than 98% of ceramic grades
- Stiff — 540 GPa (78.3 Msi), better than 86% of ceramic grades
Limitations
- High embodied carbon — 210 kg CO₂/kg, worse than 100% of ceramic grades
- Heavy — 14.55 g/cm³ (0.526 lb/in³), worse than 92% of ceramic grades
TaC SPS properties
Typical room-temperature values for TaC SPS; 11 are specific to this condition. Other listed values are TaC reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
TaC SPS has a density of 14.55 g/cm³ (0.526 lb/in³), heavier than 92% of ceramic grades. It melts at 3,880°C (7,016 °F).
Mechanical10
The elastic modulus is 540 GPa (78.3 Msi).
Thermal5
TaC SPS is rated for continuous service to 2,400°C (4,352 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 55% of ceramic grades. Thermal expansion is 6.3 µm/m·K (3.5 µin/in·°F).
Electrical2
TaC SPS has an electrical resistivity of 2.5×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (80/100), better than 56% of ceramic grades.
Sustainability3
Producing a kilogram of TaC SPS takes about 3,200 MJ of energy and emits 210 kg of CO₂ — more than 99% of ceramic grades. Typical recycled content is 10%.
Manufacturability3
TaC SPS's machinability is not recommended (4/100, worse than 85% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with TaC SPS
Is TaC easy to machine?
Green machining before sintering is the practical route; fired TaC is finished only by diamond grinding, lapping or — thanks to its metallic conductivity — wire/sinker EDM.
Can TaC be welded?
Not weldable; joined by active brazing (Ti/Zr-bearing fillers), diffusion bonding to refractory metals, or co-sintering with a metal binder.
Can TaC be formed, bent or molded?
Powder route only: cold isostatic or die pressing then hot pressing/SPS at 1800–2100 °C, or pressureless sintering above 2200 °C with C/B or metal aids; slip and tape casting are used for thin UHTC layers.
What surface finishes work on TaC?
Diamond lapping gives a mirror, dark grey metallic surface; no plating or anodizing — for oxidizing service apply SiC/HfC-bearing or CVD coatings.
TaC 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 |
|---|---|---|
| C (total)stoichiometric TaC = 6.22 wt% C | 6 – 6.4 | 6.2 |
| C (free)free/uncombined carbon in powder grades | ≤ 0.2 | 0.08 |
| Ooxygen pickup on fine powder | ≤ 0.3 | 0.15 |
| N | ≤ 0.1 | 0.03 |
| NbNb is the main natural companion of Ta; higher in TaC-NbC mixed grades | ≤ 0.5 | 0.15 |
| Fe | ≤ 0.05 | 0.02 |
| Ta≈93.8 wt% at stoichiometry | balance | — |
TaC SPS — frequently asked
What is TaC SPS used for?
TaC SPS is typically used for cemented carbide tool grain refiner, rocket nozzle throat inserts, wear-resistant coatings and UHTC composites. In short: highest-melting carbide phase; densest of the carbides; EDM-capable ceramic.
Is TaC SPS easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 85% of ceramic grades). Green machining before sintering is the practical route; fired TaC is finished only by diamond grinding, lapping or — thanks to its metallic conductivity — wire/sinker EDM.
Can TaC SPS be welded?
Not weldable; joined by active brazing (Ti/Zr-bearing fillers), diffusion bonding to refractory metals, or co-sintering with a metal binder.
What surface finishes work on TaC SPS?
Diamond lapping gives a mirror, dark grey metallic surface; no plating or anodizing — for oxidizing service apply SiC/HfC-bearing or CVD coatings.
Can TaC SPS be formed, bent or molded?
Powder route only: cold isostatic or die pressing then hot pressing/SPS at 1800–2100 °C, or pressureless sintering above 2200 °C with C/B or metal aids; slip and tape casting are used for thin UHTC layers.
What is the maximum service temperature of TaC SPS?
TaC SPS is rated for continuous use to about 2,400°C (4,352 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Handbook of Refractory Carbides and Nitrides — Noyes / William Andrew (H.O. Pierson) (1996)
- Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- CRC Materials Science and Engineering Handbook — CRC Press (2016)
- Ultra-High Temperature Ceramics: TaC/HfC property compilations (J. Am. Ceram. Soc. review data) — American Ceramic Society (2018)
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.