PEEK properties
PEEK is a premium high-performance thermoplastic combining high strength, stiffness, and an exceptional service temperature with excellent chemical resistance. It performs where most plastics fail, in aerospace, medical, and demanding industrial parts.
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength | 14,000 psi (97 MPa) |
| Flexural modulus | 590,000 psi (4.1 GPa) |
| Elongation at break | 30% |
| Hardness | Rockwell M99 |
Physical properties
| Property | Value |
|---|---|
| Density | 0.047 lb/in³ (1320 kg/m³) |
| Melting point | about 343 °C |
Thermal properties
| Property | Value |
|---|---|
| Max service temperature | about 250 °C continuous |
| Thermal expansion | 47 µm/m·°C |
| Thermal conductivity | 0.25 W/m·K |
Values are typical for the grade and condition shown. Actual properties vary with temper, heat treatment, and product form, so use these for comparison and preliminary design and confirm against material certificates for final work.
Compare with other materials
See the Material Properties Comparison, Yield Strength, and Density charts.
Typical uses
PEEK is used for aerospace components, medical implants, high-temperature bearings and seals, semiconductor parts, and demanding pump and valve components. Its strength and heat resistance let it replace metal where weight, chemical attack, or temperature rule out other plastics.
How it compares
PEEK is the strongest and most heat resistant of the common machinable plastics, far above nylon, Delrin, or polycarbonate, and it resists most chemicals. The trade-off is high cost, so it is reserved for parts that genuinely need its extreme performance.
FAQ
What makes PEEK special?
It combines metal-rivaling strength and stiffness with continuous service near 250 C and excellent chemical resistance, well beyond ordinary engineering plastics.
What is PEEK used for?
Aerospace parts, medical implants, high-temperature bearings and seals, and semiconductor and chemical components needing extreme performance.
Why is PEEK expensive?
It is a complex high-performance polymer that is costly to produce and to machine, so it is used only where its strength and heat resistance are essential.