Tribological behavior of Cu-15Ni-8Sn/graphite under sea water, distilled water and dry-sliding conditions

Abstract

The tribological behaviors of Cu-15Ni-8Sn/graphite composites with the graphite content of 38 vol.% against AISI321 stainless steel under dry-sliding, deionized water and sea water were investigated on a block-on-ring configuration. The results indicated that the friction coefficient was the lowest under dry-sliding, and the highest in deionized water. The wear rate decreased to reach the minimum value of 1.39×10-¹⁵ m³/(Nm) in sea water and in deionized water, it increased to the maximum value of 5.56×10-¹⁵ m³/(Nm). The deionized water hindered the formation of tribo-oxide layer and lubricating film, which resulted in the largest friction coefficient and wear rate. In sea water, however, the corrosion products comprised of oxides, hydroxides and chlorides were found on the worn surface, and the compacted layer composed of corrosion products and graphite played an important role in keeping the excellent wear resistance. It was elucidated that the tribological behaviors of Cu-15Ni-8Sn/graphite composite were powerful influenced by the friction environments.

摘要

本文选取AISI321 不锈钢作为对偶材料,研究Cu-15Ni-8Sn/石墨复合材料(石墨含量为38 vol%) 在干摩擦、去离子水与海水三种环境中的摩擦学行为,该实验在环块式摩擦试验机上进行。结果表明: Cu-15Ni-8Sn/石墨复合材料的摩擦系数在干摩擦时最小,在去离子水中最大;此外,海水中该复合材 料的磨损率达到最小值,即1.39×10−15 m3/(N·m),在去离子水中,其磨损率增加到5.56×10−15 m3/(N·m), 达到最大值。这表明去离子水阻碍了摩擦氧化层与润滑膜的形成,导致Cu-15Ni- 8Sn/石墨复合材料表 现出较大的摩擦系数与磨损率。在海水环境中该复合材料磨损表面形成的腐蚀产物主要包括氧化物、 氢氧化物与氯化物,且该腐蚀产物与石墨构成的压实层在保持优异的耐磨性能方面具有至关重要的作 用。研究结果表明,摩擦环境显著影响Cu-15Ni-8Sn/石墨复合材料的摩擦学行为。