PEEK — The Highest-Performance Engineering Plastic

PEEK (polyether ether ketone) is the undisputed champion of engineering plastics. It combines metal-like strength, exceptional heat resistance, and outstanding chemical stability — properties no other polymer can match simultaneously.

What Makes PEEK Special?

PEEK belongs to the elite class of semi-crystalline thermoplastics. Originally developed for aerospace applications, it has since established itself across medical devices, oil & gas, semiconductor manufacturing, and other industries where failure is not an option.

What sets PEEK apart is its ability to maintain mechanical performance under extreme conditions — where other plastics simply fail.

Mechanical Properties

PEEK offers a tensile strength of approximately 100 MPa and a flexural modulus of 3500–4500 MPa. These values are comparable to many metal alloys, yet PEEK weighs only a fraction. At 1.3 g/cm³, it’s roughly six times lighter than steel (7.8 g/cm³).

In practical terms, a PEEK component can replace a metal part while saving up to 80% in weight without sacrificing strength.

Temperature Resistance

PEEK’s continuous service temperature reaches 250 °C, with short-term tolerance up to 310 °C. For comparison, POM handles about 100 °C and PA around 120 °C.

This makes PEEK the only viable polymer for many high-temperature applications, including engine components, sterilization processes, and hot fluid handling systems.

Chemical Resistance

PEEK withstands virtually all industrial chemicals, including acids, bases, hydrocarbons, and solvents. Only concentrated sulfuric acid and certain superacid-type compounds can damage it.

PEEK also excels in steam sterilization (autoclave at 134 °C), making it ideal for medical device applications.

Wear and Friction

PEEK has naturally low friction and excellent wear resistance. Carbon fiber-filled PEEK (PEEK CF30) enhances these properties further and is ideal for bearing and sliding surface applications without lubrication.

PEEK Grades

Natural PEEK

Best chemical resistance, food and medical grade compatible, highest elongation, translucent amber color.

Filled PEEK Grades

PEEK CF30 (carbon fiber): best stiffness and wear resistance. PEEK GF30 (glass fiber): improved stiffness, more economical. PEEK-bearing: optimized for bearing applications.

Properties Comparison

Property	PEEK	POM (reference)	PA66 (reference)
Tensile strength	100 MPa	65 MPa	80 MPa
Service temperature	250 °C	100 °C	120 °C
Moisture absorption	0.1%	0.2%	2.5%
Density	1.3 g/cm³	1.41 g/cm³	1.14 g/cm³
Chemical resistance	Excellent	Good	Moderate
Price (relative)	€€€€€	€	€

Typical Applications

Aerospace: Structural components, fasteners, and seals where weight savings and heat resistance are critical.

Oil & gas: Valve seats, seals, and bearings exposed to high temperatures and aggressive chemicals.

Medical: Surgical instruments, implant components, and autoclave-sterilizable parts.

Semiconductor: Wafer handling components, test socket parts, and insulation components.

Automotive: Under-hood components, transmission parts, and brake system components.

When to Choose PEEK

PEEK is the right choice when your application demands a combination of high temperature resistance, chemical stability, and mechanical strength. It’s also justified when replacing a metal part with a lighter material yields significant savings in weight or energy consumption.

PEEK is an expensive material — it can cost 10–20 times more than POM or PA. Its use is therefore justified only when cheaper alternatives cannot meet the requirements.

Interested in PEEK for your application?

We supply PEEK stock shapes in rods and sheets. Tell us about your application and we’ll help you choose the right PEEK grade.