温度对Cu-12.5Ni-5Sn-石墨自润滑复合材料摩擦学性能的影响

Effect of Temperature on Tribological Properties of Cu-12.5Ni-5Sn-Graphite Self-Lubricating Composites

采用粉末冶金方法制备出了Cu-12.5Ni-5Sn-石墨自润滑复合材料,通过改变石墨的含量来研究该复合材料的力学性能和在不同摩擦试验温度下的摩擦磨损性能,采用SEM和Raman分析磨损表面,进而讨论复合材料的摩擦、磨损和润滑机制.结果表明:复合材料的硬度和屈服强度随着石墨含量的增加而逐渐降低;温度对不同石墨含量的复合材料的摩擦磨损性能有显著的影响,在室温下,石墨质量分数为1%和3%的石墨复合材料的摩擦系数和磨损率明显小于5%石墨复合材料;在300℃下,石墨质量分数为3%时,复合材料的摩擦磨损性能最好;在500℃下,石墨质量分数为5%的石墨复合材料的摩擦磨损性能最好.在室温下,复合材料具有较好自润滑性的主要原因是形成了几乎光滑连续的石墨润滑膜.在300和500℃下,由金属氧化物和石墨组成的混合物润滑膜是复合材料保持自润滑性的主要原因.

Cu-12.5Ni-5Sn-graphite self-lubricating composites were prepared by powder metallurgy.The mechanical properties and tribological properties of the composites with different graphite contents at elevated temperatures were investigated.The worn surfaces were analyzed by using scanning electron microscopy and Raman to investigate the friction,wear and lubricating mechanism.The results show that the hardness and yield strength of composites decreased with the increase of the graphite content.The temperature had a remarkable impact for the friction and wear properties of composites.At room temperature,the friction coefficient and wear rate of composites with 1%or 3%graphite were obvious lower than that of composite with 5%graphite.At 300℃,the composite with 3%graphite had the best friction and wear properties.At 500℃,the composite with 5%graphite content had the optimal tribological properties.At room temperature,the composite with the better self-lubricating properties were mainly attributed to the formation of almost smooth and continuous graphite lubricating film.At 300℃and 500℃,the mixture lubricating film of some metallic oxides and graphite was responsible for self-lubricating performance of composites.