Abstract Fiber brushes with expanded graphite (EG) as a lubricant were successfully prepared. Compression properties of brushes filled with unbent fibers and bent fibers with different packing fractions were compared. Moreover, the friction and wear behaviors of the brushes with the same fiber packing fractions (17.5 vol%) but different EG volume contents were investigated. The effect of EG content on the tribological behavior of the fiber brush was analyzed according to the microstructure, debris, and worn surface of the brush and counterface disc. Results showed that both the elastic constant and compression strength of the brushes filled with bent fibers increased with an increase in packing fraction. Brushes filled with 17.5 vol% bent fibers had similar compression strength (2.69 MPa) but a lower elastic constant (150 N/mm) compared to the brush filled with 17.5 vol% unbent fibers (2.62 MPa and 425 N/mm). The friction coefficients and wear rates of the brushes decreased from 1.02 and 1.6 × 10−5 mm3/Nm to 0.25 and 0.28 × 10−5 mm3/Nm as the EG increased to a critical value (23.7 vol%). The worn surface and wear debris demonstrate that the wear mechanism of tin–bronze fiber brushes with EG sliding against brass discs transforms from adhesive wear to abrasive wear due to the formation of an EG lubricating film.

中文翻译：

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膨胀石墨对锡青铜纤维刷在黄铜上滑动摩擦学行为的影响

摘要 成功制备了以膨胀石墨（EG）为润滑剂的纤维刷。比较了填充有未弯曲纤维和具有不同填充率的弯曲纤维的刷子的压缩性能。此外，研究了具有相同纤维填充率 (17.5 vol%) 但不同 EG 体积含量的刷子的摩擦和磨损行为。根据刷子和配合盘的微观结构、碎屑和磨损表面分析EG含量对纤维刷摩擦学行为的影响。结果表明，填充弯曲纤维的刷子的弹性常数和压缩强度都随着填充率的增加而增加。填充有 17.5 vol% 弯曲纤维的刷子具有相似的压缩强度 (2. 69 MPa），但与填充有 17.5 vol% 未弯曲纤维（2.62 MPa 和 425 N/mm）的刷子相比，弹性常数较低（150 N/mm）。随着 EG 增加到临界值 (23.7 vol%)，电刷的摩擦系数和磨损率从 1.02 和 1.6 × 10−5 mm3/Nm 下降到 0.25 和 0.28 × 10−5 mm3/Nm。磨损表面和磨损碎片表明，由于EG润滑膜的形成，EG在黄铜盘上滑动的锡青铜纤维刷的磨损机制从粘着磨损转变为磨粒磨损。