As newly developing engineering plastic material, PEEK and PI have been approved. That they have the strongest mechanical strength and could endure the highest temperature among all the plastic material. PEEK could work at 260℃ while PI could work at 300℃ for long time. Moreover they have excellent anti-corrosion performance and could be used in strong acid and alkali environment. So generally they are used to manufacture bearings to realize precision running in rigorous environment. As the material is expensive, the costs are high. Generally the rings are made of PEEK or PI. Cage is PTFE, PEEK or PI and ball is ZrO2 or Si3N4.
