Free abrasive wear behavior of UHMWPE composites filled with wollastonite fibers

Ultra high molecular weight polyethylene (UHMWPE) composites filled with wollastonite fibers of aspect ratios 10:1, 15:1 and 20:1 have been prepared. The wollastonite fibers were modified by the silane–titanate combined modification method. The free abrasive wear of the composites was tested on a rotary disc abrasive wear tester simulating soil conditions, using quartz sand as the abrasive medium. It has been shown that the free abrasive wear of the composites was a function of the content of the fibers, the aspect ratio of the fibers, the abrasive particle sizes and the relative sliding velocity. The addition of the wollastonite fibers improved the abrasion resistance of the composites for fiber contents ≤20 wt%, with the maximum abrasion resistance being found at 10 wt%. Increasing aspect ratio of the fibers was the most important factor in improving the abrasion resistance. The wear resistance of the composites was increased by the silane–titanate combined modification of the fibers but reduced by increases in abrasive particle sizes and sliding velocity. The abrasion mechanisms of the composites have been investigated by scanning electron microscopy of the abraded surfaces. It was shown that the abrasive wear of the composites was mainly due to the plastic deformation, micro-plowing, micro-cutting and micro-cracking mechanisms.