Abstract:Four polybutylene terephthalate(PBT) composite materials,which were modified by PTFE,wollastonite,and Kevlar fibers with mass fractions of 5% and 10% respectively,were prepared by meltblending method.The tribological properties of the modified PBT composite materials were analyzed under water lubricated condition.The results show that the prepared PBT composite materials have relatively stable friction coefficient under the medium and low speed.But under the high speed,the friction coefficients of PTFE/PBT and wollastonite/PBT composite materials are increased gradually,while that of Kevlar/PBT composite materials are decreased gradually.Among them,Kevlar/PBT composite materials with a mass fraction of 5% aramid fiber have the smallest average friction coefficient and the highest stability of friction coefficient within the test time.The wear losses of Kevlar/PBT composite materials are significantly smaller than that of PTFE/PBT and wollastonite/PBT composite materials during the test time,and the Kevlar/PBT composite materials with a mass fraction of 5% aramid fiber have the smallest wear loss.The wear mechanism of the Kevlar/PBT composite materials is mainly fatigue wear,PTFE/PBT composite materials are mainly adhesive wear accompanied by a slight fatigue wear,wollastonite/PBT composite materials are mainly abrasive wear.