Effects of expanded graphite on the current carrying tribological properties of phosphor-bronze fiber brush
LUO Bo1, JING Guiru2, LI Changjiang2, ZHANG Lei1
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. Aerospace System Engineering Shanghai, Shanghai 201109, China
Abstract：A fiber brush was prepared by rolling the fiber bundle with expanded graphite paper using phosphor-bronze fibers with diameter of 50 μm as the main material and expanded graphite paper as the lubricant. The effects of expanded graphite content on the electric contact property and current carrying tribological properties of the fiber brush were studied. The results show that, a three-dimensional brush structure with uniform dispersion of fibers was constructed through bending the phosphor-bronze fibers, which leads to a lower elastic constant and appropriate compression strength of the fiber brush. The bent phosphor-bronze fiber brush, compared to the unbent phosphor-bronze fiber brush with the same packing fraction of fiber (17.5%), possesses slightly higher compressive strength (2.69 MPa vs 2.62 MPa) and lower elastic constants (149.5 N/mm vs 428.8 N/mm). The friction and wear properties of the brushes increase while the electrical contact property decreases. With the content of expanded graphite increasing from 6.2% to 29.1%, the friction coefficient decreases from 0.67 to 0.25, and the contact voltage drop increases from 244.86 mV to 427.81 mV. Otherwise, the asymmetric wear behavior of the phosphor-bronze fiber brush can be suppressed by the lubricating effect of expanded graphite. The wear rates of the negative and positive brush without expanded graphite are 5.83×10-9 m/m and 1.12×10-8 m/m respectively. As the content of expanded graphite increases to 29.1%, the wear rate of the negative and positive brush decrease to 0.44×10-9 m/m and 0.53×10-9 m/m respectively.
罗博, 经贵如, 李长江, 张雷. 膨胀石墨对磷铜纤维电刷载流摩擦学性能的影响[J]. 粉末冶金材料科学与工程, 2018, 23(2): 147-156.
LUO Bo, JING Guiru, LI Changjiang, ZHANG Lei. Effects of expanded graphite on the current carrying tribological properties of phosphor-bronze fiber brush. Materials Science and Engineering of Powder Metallurgy, 2018, 23(2): 147-156.
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2018, Vol. 23 
