Study On Preparation And Properties Of3-D Braided Carbon Fiber Reinforced Polyether-ether-ketone Composites

Polyether-ether-ketone （PEEK） is a thermoplastic resin with excellentcomprehensive performance which has high temperature resistance, corrosionresistance, wear resistance and resistant to radiation that make it widely used inaerospace, machinery, petrochemical industry, nuclear power, rail transit, medical andso on. Three-dimensional （3-D） braided composites are excellent materials for surgery,aviation and other applications because of their good properties such as high specificstrength. So3-D braided carbon fiber reinforced PEEK (C_3D/PEEK) compositesprepared through fiber hybrid braiding and hot-pressing process will have wideapplications in high load, temperature and wear environment.In this work,3-D braided carbon fiber reinforced PEEK composites were preparedby3-D braided plus vacuum hot-pressing technology, preparation process of highcontent of carbon fiber composites and the effects of carbon fiber volume on themechanical properties of the composites were also analyzed. Furthermore, the frictionand wear characteristics of the composites were researched, and the wear mechanismsof the composites in different conditions were deeply discussed in this paper. Thenthis experimental investigation can be used to evaluate the feasibility of thecomposites used as high-speed train bogie gear materials.It was shown that C_3D/PEEK composites with excellent appearances and goodinterfacial adhesions could be prepared by vacuum hot-pressing at370℃and0.5MPa pressure for2h pre-dryness treatment when the carbon fiber volume was lowerthan54%. The mechanical properties of composites could be evidently improved byoptimization of fiber volume fraction and fiber surface treatment. But as forcomposites with fiber volume fraction equal to or more than60%, preparation processparameters should be changed to temperature,390℃, pressure,0.5MPa andpre-dryness time,3h. The results showed that the mechanical properties such asflexural strength and modulus of C_3D/PEEK composites increased and the impacttoughness with almost linear increased with the increase of the carbon fiber volumefraction. When the carbon fiber volume fraction is more than60%, this rising trendbecame slow, and composites will transfer from plastic to brittle. The friction andwear test showed that the C_3D/PEEK composites wear resistance increased in contrastto pure PEEK. The friction coefficient and wear rate of the C_3D/PEEK compositesdecreased with the improvement of carbon fiber volume fraction of the composites. The C_3D/PEEK composites showed better friction and wear characteristics when itwas under appropriate lubrication medium. The deionized water and sea waterlubrication have not affected the wear mechanism which occurs abrasive wear.Especially the composites shows very excellent tribological properties when it waswear with the thermoplastic PEEK resin. And abrasive wear is dominant with fewadhesion wear in this situation. The existing research properties of C_3D/PEEKcomposites meet some of the plastic gears performance requirements and it isexpected to become a new kind of high-speed train bogie plastic gear materials.