Shape-controllable synthesis of mullite whisker and its effect on tribological behavior of resin-based friction materials

The development and design of fillers aid in improving the tribological performances of friction materials. Herein, the effects of the aspect ratio of mullite whisker on the tribological properties were studied. Mullite whiskers were prepared by the sol–gel process and the aspect ratio of the whisker was controlled by introducing aluminum fluoride (AlF 3 ). The aspect ratio increased significantly at first and then decreased with increasing the contents of AlF 3 . The experimental results show that higher aspect ratio whiskers stabilized the friction coefficient while increased the wear rate. In addition, the composite with mullite whisker grown in excessive AlF 3 (20%) resulted in a higher friction coefficient compared to adding inadequate AlF 3 (10%). The Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX) results indicated that higher aspect ratio of whisker was more likely to fall off from matrix which sequentially being compacted and formed contact plateaus during the friction process. In conclusion, it was found that abrasive wear and adhesive wear were the dominant wear mechanism. Highlights The aspect ratio of mullite whisker was controlled within the range of 6 ~ 21. The tribological properties of whiskers reinforced composites were studied. The morphology of the mullite whisker affects the friction stability. The flaky mullite whisker can improve wear resistance of the composites.