PBI
also Celazole
PBI (Celazole) is a fully aromatic, amorphous, non-melting high-performance polymer with the highest heat resistance, compressive strength and stiffness of any commercially available unfilled thermoplastic: Tg ≈ 427 °C, continuous use to about 310 °C in air, brief excursions to ~500 °C, 160 MPa tensile and 5.9 GPa modulus.
PBI grades and fills
PBI is supplied in 3 conditions, soft to hard.
Compare all 3 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
T-Series lubricated PBI/PEEK bearing grade | Pick for dry-running bushings, wear rings and thrust washers at elevated temperature where a low, stable friction coefficient is required. | 95 | 2.5 | ||
T-Series filled PBI/PEEK grade for vacuum/semiconductor service | Pick for plasma-chamber and vacuum-environment wear parts needing low outgassing plus wear resistance rather than maximum strength. | 100 | 2.5 | 88 Shore D | |
T-Series unfilled PBI/PEEK alloy | Pick when full PBI temperature is not needed and better toughness, easier machining and lower cost matter (structural insulators, seal rings to ~260 °C). | 130 | 5 |
Supply forms, finishes and certifications
Ways PBI is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
UnfilledDefault | Virgin PBI | Standard supply |
What is PBI?
PBI (Celazole) is a fully aromatic, amorphous, non-melting high-performance polymer with the highest heat resistance, compressive strength and stiffness of any commercially available unfilled thermoplastic: Tg ≈ 427 °C, continuous use to about 310 °C in air, brief excursions to ~500 °C, 160 MPa tensile and 5.9 GPa modulus. Stock shapes are made by high-pressure sinter (compression) moulding and then machined into semiconductor test sockets, wafer-handling parts, hot-gas valve seats and insulator bushings. Limits are extreme cost, brittleness (3 % elongation, low notched impact), moisture pickup that requires annealing and dimensional control, and no melt processing or welding; PAI is the cheaper step down. PBI has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 427°C (801 °F). PBI has a tensile strength of 160 MPa (23.2 ksi), stronger than 96% of polymer grades. Elongation at break is 3% and the elastic modulus is 5.9 GPa (0.856 Msi).
What is PBI used for?
- Semiconductor test sockets
- Wafer-handling parts
- Hot-gas and valve seats
- Insulator bushings
- Seals and back-up rings
- Cryogenic-to-high-temperature structural insulators
- Aerospace radomes
Advantages
- High service temperature — 310°C (590 °F), better than 100% of polymer grades
- Conducts heat well — 0.41 W/m·K (0.237 BTU/hr·ft·°F), better than 94% of polymer grades
- Good corrosion resistance — 92/100, better than 91% of polymer grades
- Stiff — 5.9 GPa (0.856 Msi), better than 89% of polymer grades
- Good UV / weathering resistance — 70/100, better than 83% of polymer grades
Limitations
- Limited formability — 5/100, worse than 95% of polymer grades
- Difficult to weld — 5/100, worse than 89% of polymer grades
- Limited ductility — 3%, worse than 83% of polymer grades
PBI properties
Typical room-temperature values in the Unfilled condition; bars are the position among polymer grades.
Physical4
PBI has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 427°C (801 °F).
Mechanical11
PBI has a tensile strength of 160 MPa (23.2 ksi), stronger than 96% of polymer grades. Elongation at break is 3% and the elastic modulus is 5.9 GPa (0.856 Msi).
Thermal9
PBI is rated for continuous service to 310°C (590 °F). It conducts heat at 0.41 W/m·K (0.237 BTU/hr·ft·°F), better than 94% of polymer grades. Thermal expansion is 23 µm/m·K (12.8 µin/in·°F).
Electrical5
PBI is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 91% of polymer grades. UV resistance is very good.
Sustainability1
Typical recycled content is 0%.
Manufacturability4
PBI's machinability is fair (50/100, worse than 73% of polymer grades); weldability not recommended (5/100); formability not recommended (5/100).
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 polymer family
Yield strength against density for every polymer grade FabDigit runs. PBI is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PBI
Is PBI easy to machine?
Machine like a hard, brittle ceramic-filled plastic: sharp polished carbide (or PCD for filled grades), high speed, light feeds, minimal heat, generous corner radii; parts are notch-sensitive and stock should be kept dry/annealed to control post-machining growth.
Can PBI be welded?
Not weldable or heat-staked — PBI does not melt; join by fasteners, press fit, adhesives (epoxy after abrasion/primer) or mechanical clamping.
Can PBI be formed, bent or molded?
Not melt-processable: shapes are produced by high-temperature/high-pressure sinter (compression) molding of resin powder, then finish-machined; no injection molding, extrusion or thermoforming.
Manufacturability
The process limits FabDigit applies to PBI. Every PBI part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair50 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 400 / 500 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 10× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Not Recommend5 / 100 |
|---|---|
| Weldability | Not Recommend5 / 100 |
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
PBI 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.
| Element | Spec limit (wt %) |
|---|---|
| 3,3'-diaminobenzidine (monomer)amine monomer unit | — |
| diphenyl isophthalate (monomer)ester monomer unit | — |
| poly[2,2'-(m-phenylene)-5,5'-bibenzimidacondensation polymer of 3,3'-diaminobenzidine (tetraaminobiphenyl) with diphenyl isophthalate; unfilled grade | balance |
What surface finishes work on PBI?
No plating or anodizing; typical finishing is fine machining/lapping, light bead-blast or vapor-honing, and thorough drying/annealing cycles before dimensional inspection — natural color is dark bronze-brown to black.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Organic Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to PBI in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Celazole
- Also called
- Polybenzimidazole
How much does PBI cost?
PBI is a specialty-cost polymer ($$$$$), pricier than about 99% 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.
PBI — frequently asked
What is PBI used for?
PBI is typically used for semiconductor test sockets, wafer-handling parts, hot-gas and valve seats, insulator bushings, seals and back-up rings and cryogenic-to-high-temperature structural insulators. In short: highest temperature plastic.
What is the tensile strength of PBI?
PBI has a typical tensile strength of 160 MPa (23.2 ksi) — stronger than 96% of polymer grades. Strength varies by condition: see the 3 listed tempers.
Is PBI easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 73% of polymer grades). Machine like a hard, brittle ceramic-filled plastic: sharp polished carbide (or PCD for filled grades), high speed, light feeds, minimal heat, generous corner radii; parts are notch-sensitive and stock should be kept dry/annealed to control post-machining growth.
Can PBI be welded?
Not readily — weldability is rated not recommended (5/100). Not weldable or heat-staked — PBI does not melt; join by fasteners, press fit, adhesives (epoxy after abrasion/primer) or mechanical clamping.
What surface finishes work on PBI?
No plating or anodizing; typical finishing is fine machining/lapping, light bead-blast or vapor-honing, and thorough drying/annealing cycles before dimensional inspection — natural color is dark bronze-brown to black.
Can PBI be formed, bent or molded?
Not melt-processable: shapes are produced by high-temperature/high-pressure sinter (compression) molding of resin powder, then finish-machined; no injection molding, extrusion or thermoforming.
What is the maximum service temperature of PBI?
PBI is rated for continuous use to about 310°C (590 °F), and briefly to 500°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PBI cost?
PBI is a specialty-cost polymer ($$$$$), pricier than about 99% 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.
Can FabDigit make parts in PBI?
Yes — PBI is available for CNC machining, sheet metal and injection molding; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- Celazole PBI U-60 / T-Series stock shapes technical data — Celanese / Boedeker & Drake Plastics distributor data (2023)
- TECAPBI blue product datasheet — Ensinger (2022)
- Engineered Materials Handbook, Vol. 2: Engineering Plastics — ASM International (1988)
- High-performance polymer property tables (PBI) — CAMPUS / UL Prospector (2023)
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.