Effects of reinforcements on the hardness of composite seal rings

Composite seal rings are alternate high-performance materials for supplying to engines and compressors in several industries. Polytetrafluoroethylene (PTFE) and Polyetheretherketone (PEEK) seals reinforced by carbon powder and glass fibers were investigated. The seal specimens were heated at 150–200 °C for a duration of 24 h. The hardness and microstructure of specimens were observed after the test. Taguchi technique was used for design of experiment to analyzed the parameters that affected to the seal hardness. The hardness of all samples decreased when increasing temperature, and the hardness of PTFE and PEEK with carbon powder slightly increased after heating at higher temperature. The PEEK with 30% carbon showed the highest hardness compared to the others at temperature of 150 and 200 °C. The carbon reinforcements promoted increasing hardness of the composite seal rings. Besides, the reinforcements showed a good distribution in the composite matrix which was nearly the same as the microstructure of the compressor seal ring used in industrial parts.