Study on Tribological Properties of Modified ATP C ontent on UHMWPE Based Water-lubricated Bearin g Materials

The ultra high molecular weight polyethylene (UH MWPE) bearing material often suffers serious wear under low speed and heavy load condition. The tribological properties of UHMWPE bearing material can be greatly improved by modif ication. Atapulgite (ATP), as a modified filler, can enhance the mechanical properties of the material and improve its frictiona l properties, but agglomeration effect limits its dispersion in th e matrix material. The surface modification of ATP can achiev e uniform blending between ATP and the matrix. ATP modifie d by silane coupling agent KH570 was prepared by surface che mical coating modification method. The composite material wa s blended with UHMWPE and compared with pure UHMWPE. Under the condition of water lubrication, the change of frictio n coefficient of composites under different loading and rotating speed conditions and the influence of material filling content o n the wear performance of composites under low speed and he avy load conditions ( $v=0.55$ m/s, $F_{z}=55$ N) were studied. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron s pectroscopy (XPS) and electronic universal material testing ma chine were used to characterize the ATP modification effect an d the important mechanical properties of the composites. At th e end of the experiment, the wear surface morphology of the co mposites and their duals was observed by surface profilometer and confocal laser microscope, and the wear mechanism was a nalyzed. The results show that the silane coupling agent KH570 has a good effect on ATP modification, and the Shore hardnes s of the material can be increased by filling ATP modification, and the tensile property of the material decreases with the incr ease of filling content. Compared with the pure UHMWP mate rial, the friction coefficient of the composites is lower. An appr opriate amount of ATP filling can improve the wear surface m orphology and reduce the volume wear rate. In the experiment, the modified ATP content of 1w% material has the best tribolo gical properties, and its friction coefficient and volume wear ra te at low speed and heavy load are reduced by 21.45% and 12.8 6%, respectively, compared with pure UHMWPE.