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PEEK Material selection guide

PEEK material selection depends on the required combination of mechanical strength, stiffness, wear resistance, chemical resistance, dimensional stability, electrical behavior, operating temperature and processing method. Virgin PEEK is generally selected for ductility, chemical resistance and purity; GF30 PEEK for stiffness and dimensional stability; CF30 PEEK for high modulus, low thermal expansion and wear resistance; bearing-grade PEEK for low-friction and dry-running applications; and ESD PEEK when controlled electrostatic dissipation is required. The final grade should be selected according to the application, processing method, filler formulation and verified material data sheet.

Quick PEEK Grade Selection

Quick Selection table

PEEK Grade

Best For

Main Advantage

Main Limitation

Typical Applications

Virgin PEEK

Chemical resistance, ductility, purity

Toughness & chemical resistance

Lower stiffness than reinforced grades

Chemical equipment, seals, medical components

GF30 PEEK

Structural components

High stiffness & dimensional stability

More brittle than virgin PEEK

Structural parts, precision components

CF30 PEEK

High stiffness, wear, low CTE

Very high modulus & low thermal expansion

More formulation-dependent

Wear parts, precision components

Bearing Grade PEEK

Sliding and dry-running parts

Low friction & wear resistance

Not optimized for every structural application

Bearings, bushings, seals

ESD PEEK

Static-sensitive applications

Controlled electrostatic dissipation

Electrical properties must be verified

Semiconductor, electronics

PEEK Material grades

Unfilled (Virgin) grade

High purity:Medical grade can be Implant,Medical fiber filled grade can only work as mrdicaldevice
High toughness & high elongation at break(45%)
HIgh insolution:10^16Ω·cm
Excellent Anti-fatigue

Limited:The HDT is only 152°C，altough it can work under 260°C for a long time,

but load-bearing capacity is insufficient in high temperatures.

30%Carbon fiber filled grade(CF30)

maximum stiffness:8× the stiffness of unfilled (23 GPa vs 4.1 GPa)
High HDT:315°C
3×thermal conductivity of unfilled:0.95W/(m·K)
Wear resistance & high strength
Excellent dimensional stability

Limited:electrically conductive (10^5 Ω·cm), so it is disqualified wherever dielectric isolation is required; it is also the most abrasive grade to machine (PCD tooling recommended) and the most expensive.

Electrostatic dissipation grade(ESD/Anti-static)

Controlled static dissipation — Surface resistivity held at 10^6–10^9 Ω/sq, between insulating and conductive, so charge bleeds away steadily instead of building up and discharging at once.
Protects sensitive electronics — Prevents ESD damage to semiconductors, wafer carriers and test sockets during handling.
Permanent, not a coating — The dissipative network runs through the whole part: no dependence on humidity, no wear-off from cleaning.

30%Glass fiber filled grade(GF30)

High stiffness:3× the stiffness of unfilled (11.3 GPa vs 3.8 GPa)
High HDT:315°C
Remain HIgh insolution:10^16Ω·cm
Excellent dimensional stability

Limited:glass fibre abrades mating surfaces. Verify before specifying GF30 as a sliding or bearing component; use the bearing grade or CF30 instead.

Bearing grade(CF + graphite + PTFE)

highest PV limit in sliding duty:lowest coefficient of friction and the best self-lubrication
Low coefficient of friction:wear resistance under high speed and high pressure is better than PEEK CF30.
3×thermal conductivity of unfilled:0.87W/(m·K)
Remain HIgh insolution:10^10Ω·cm
Excellent dimensional stability

Limited:Bearing grade is wear resistance,it's mechanical strength is lower than GF30 and CF30,it not suitable to use as structural material

When toughness matters more than strength?

Although the mechanical strength and HDT of PEEK resin are lower than those of reinforced PEEK, the excellent crack resistance and ductility of PEEK resin only show their advantages in the following situations:

The part must deform during assembly - for example, quick-release joints, interference fits, movable hinges, press-fit structures. CF30 will crack at an elongation of 1.7%, while un-filled materials will not crack at an elongation of 45%.
May be subjected to impact or sudden overload - the part absorbs energy through deformation instead of breaking.
There are notches, scratches or stress concentrations, and sudden failure is unacceptable - cracks will extend slowly and obviously, rather than spreading unstably.
Complex geometries or multi-axis loads - un-filled PEEK is isotropic, so its performance is not affected by direction. Reinforced grade materials must be designed for the most unfavorable fiber orientation, which is usually much lower than the values in the data sheet.
High-frequency vibration environments requiring damping - such as compressor valve plates, vibration supports, spring elements, etc.

PEEK Material performance by grades

PEEK material Mechanical Properties

Item	Test Standard	Unfilled PEEK	30% Glass fiber filled PEEK	30% Carbon fiber filled PEEK	Bearing grade PEEK	ESD PEEK
Tensile Strength (23℃)	ISO 527	100MPa	175MPa	260Mpa	140Mpa	210MPa
Elongation at Break (23℃)	ISO 527	45%	2.7%	1.7%	2.2%	2.1%
Flexural Strength (23℃)	ISO 178	165MPa	265MPa	380MPa	230MPa	310MPa
Flexural Modulus (23℃)	ISO 178	4.1GPa	11.3GPa	23GPa	11.5GPa	16GPa
Charpy Impact Strength (unnotched)	ISO 179/1eU	No-break	55KJ/m²	45KJ/m²	35KJ/m²	45KJ/m2
Charpy Impact Strength (notched)	ISO 179/eA	7KJ/m²	8KJ/m²	9KJ/m²	5KJ/m²	7KJ/m2

Flexural strength of PEEK grades vs temperature

Source:(Typical values, ISO 527 / ISO 178,Values at 23 °C per PRES datasheets; temperature-dependent trend after Victrex PEEK Properties Guide)

Above Tg, PEEK's strength declines significantly. Its crystalline regions preserve part of the stiffness and strength and hold the structure together, so PEEK does not soften and collapse the moment Tg is reached — but the performance has already dropped. The measured curves show unfilled PEEKretaining only around 10–20% of its room-temperature strength by 200 °C.

The 260 °C continuous-service rating must therefore be read correctly: it is a thermal-oxidative ageing limit, established against standards such as UL 746B, certifying that PEEK will not chemically degrade during prolonged exposure. It does not mean PEEK retains most of its load capacity at 260 °C.

Reinforced grades HDT is far higher — 315 °C for GF30 and 336 °C for CF30 against 152 °C for unfilled —and although their strength also falls above Tg, the load they still carry remains far greater than unfilled PEEK at the same temperature. At 180 °C, CF30 holds roughly 166 MPa in flexure where unfilled PEEK is down to about 20 MPa.

PEEK material Thermal Properties

Item	Test Standard	Unfilled PEEK	30% Glass fiber filled PEEK	30% Carbon fiber filled PEEK	Bearing grade PEEK	ESD PEEK
Melting point	ISO11357	343°C/649°F	343°C/649°F	343°C/649°F	343°C/649°F	343°C/649°F
Glass Transition Temperature	ISO11357	143°C/289.4°F	143°C/289.4°F	143°C/289.4°F	143°C/289.4°F	143°C/289.4°F
Heat Deflection Temperature(HDT)	ISO 75A/B	152°C/306°F	315°C/599°F	336°C/637°F	293°C/559°F	325°C/617°F
Long term using Temperature	-	260°C/500°F	260°C/500°F	260°C/500°F	260°C/500°F	260°C/500°F
Short term using Temperature	-	300°C/572°F	300°C/572°F	300°C/572°F	300°C/572°F	300°C/572°F
Thermal Expansion Coefficient(below Tg)	ISO 11359	45ppm/K	18ppm/K	5ppm/K	15ppm/K	8ppm/K
Thermal Expansion Coefficient(over Tg)	ISO 11359	120ppm/K	18ppm/K	6ppm/K	20ppm/K	8ppm/K
Thermal Conductivity	ISO /CD22007-4	0.29W/(m·K)	0.32W/(m·K)	0.95W/(m·K)	0.86W/(m·K)	0.95W/(m·K)

PEEK material Electrical Properties

Item	Test Standard	Unfilled PEEK	30% Glass fiber filled PEEK	30% Carbon fiber filled PEEK	Bearing grade PEEK	ESD PEEK
Dielectric Strength (2mm)	IEC 60243-1	20 kV/mm	19kV/mm	-	-	-
Dielectric Constant	IEC 62631	3.0	3.3	-	-	-
Volume Resistivity	IEC 60093	10^16 Ω·cm	10^16 Ω·cm	10^5 Ω·cm	10^10 Ω·cm	10^6-10^9 Ω·cm

PEEK material Physical properties

4Item	Test Standard	Unfilled PEEK	30% Glass fiber filled PEEK	30% Carbon fiber filled PEEK	Bearing grade PEEK	ESD PEEK
Density	ISO 1183	1.3g/cm³	1.51g/cm³	1.4g/cm³	1.44g/cm³	1.37g/cm³
Water Absorption (23℃, 24Hrs)	ISO 62-1	0.07%	0.04%	0.04%	0.04%	0.05%
Shore D Hardness	ISO 868	85D	88D	88D	83D	86D