Effects of Ni-Coated Graphite Flake on Braking Behavior of Cu-Based Brake Pads Applied in High-Speed Railway Trains
Effects of Ni-Coated Graphite Flake on Braking Behavior of Cu-Based Brake Pads Applied in High-Speed Railway Trains
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DOI：
10.1115/1.4043714
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
Peng Zhang;Lin Zhang;K. Fu;Peifang Wu;Jingwu Cao;Cairang Shijia;X. Qu
中科院分区：
文献类型：
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作者：
Peng Zhang;Lin Zhang;K. Fu;Peifang Wu;Jingwu Cao;Cairang Shijia;X. Qu
采用粉末冶金法分别制备了镍包石墨片和未包石墨片的高速列车铜基刹车片。采用盘式制动器结构的制动片试验装置，研究了不同制动速度和制动压力下制动片的制动性能。与含有未涂覆的石墨片（指定为GF）的制动片相比，含有Ni涂覆的石墨片（指定为NGF）的制动片在较低的制动速度和压力下表现出类似的制动性能。然而，NGF在制动过程中表现出更稳定的摩擦系数、更低的线性磨损损失和更低的最高温度，350公里/小时，1.5兆帕。镀镍石墨表面的镀镍层可以将铜与石墨之间的机械结合转变为扩散结合，从而使铜与石墨之间有更强的界面结合。多元线性回归分析表明，由于NGF具有较好的耐热性，其平均摩擦系数对制动压力的敏感性大于对制动速度的敏感性，而GF的平均摩擦系数和线磨损量主要受制动速度的影响。
Cu-based brake pads applied in high-speed railway trains containing Ni-coated graphite flake and uncoated graphite flake were fabricated by powder metallurgy. The braking properties of the brake pads were investigated by a scaled down testing apparatus with the pad-on-disk configuration under various braking speeds and braking pressures. Compared with the brake pads containing uncoated graphite flake (designated GF), the brake pads containing Ni-coated graphite flake (designated NGF) exhibits a similar braking performance at lower braking speed and pressure. However, NGF shows more stable friction coefficient, lower linear wear loss, and lower maximum temperature during the braking process at worse braking conditions, e.g., 350 km/h, 1.5 MPa. The Ni-coating on the surface of Ni-coated graphite can transfer the mechanical bonding between copper and graphite to diffusion bonding so that there is a stronger interface bonding between copper and Ni-coated graphite. Further, the multiple linear regression analyses reveal that the mean friction coefficient of NGF is more sensitive to braking pressure than braking speed because of the better thermal resistance of NGF, while the mean friction coefficient of GF and the linear wear loss are mainly affected by braking speed.