Effect Of High Temperature And High Pressure Water Environment On Friction And Wear Properties Of Polyetheretherketone Composites

30% carbon fiber reinforced polyetheretherketone composite(PEEK450CA30,referred to as CA30),which is Widely used in aerospace,navigation and nuclear power fields,is easy to be worn under many conditions of service.In this paper,CA30 and ?-irradiated CA30(referred to as RCA30)were soaked in high temperature and high pressure water environment for a long time,the friction and wear properties were tested on the wear tester,when the sample block rubbed against the Stellite alloy ring at a sliding speed of 2 m/s under water lubrication at 500 N.With the help of XRD?FTIR?DSC and TGA,the structure and thermal properties of the PEEK composites were analyzed,The tribological properties of the material were analyzed by friction coefficient,wear contour,specific wear rate and SEM image.It was found that the high temperature and high pressure water environment increased the crystallinity of the PEEK composites without,changing its chemical structure,during the aging process,chemical bonds were broken and compounds were formed.The high temperature and high pressure water environment reduced the melting point of PEEK composites,and it still maintained excellent thermal stability at 700 °C.PEEK composites had stable tribological properties whose friction coefficient were fluctuated around 0.02 in the friction and wear test.The wear contour was measured and it was found that the wear scar of aged PEEK composites were lighter and narrower than the original sample,the reason may be that the aging made the carbon fiber peel off more,bearing part of the load and improving the anti-adhesion level;It was found that the specific wear rate of the PEEK composites decreased with the immersion time,which means that the aging increased wear resistance of the material.At the same time,the specific wear rate of RCA30 is much lower than that of CA30,indicating that the irradiation improved the wear resistance of the material,?-ray irradiation and high temperature and high pressure reduced RCA30's specific wear rate.It was found that the longer the immersion time,the more defects such as cracks and holes were observed from SEM image.It indicated that PEEK composites had a slight adhesive wear at the beginning,then the adhesive wear was weakened and changed to fatigue wear,and the fatigue wear and abrasive wear were its major wear mechanism after a long time of testing.