石墨烯含量对铜基复合材料的导电、导热、耐腐蚀和力学性能的影响

摘要

采用电场压力激活辅助合成工艺(Field activated and pressure assisted synthesis process(FAPAS))制备铜基石墨烯复合材料,研究不同的石墨烯含量对铜基体材料的微观结构和性能的影响机理.结果 表明,石墨烯的添加能提高材料的位错密度、阻止位错在晶界移动,硬度提升17.6％;由于石墨烯添加量少,对铜基复合材料的位错密度和晶粒尺寸影响有限,片状的石墨烯能有效地弥补制备产生的缺陷,使材料的热导率和电导率分别提升2.9％和4.4％;石墨烯的添加使腐蚀电池两极间的电位差减小,降低了铜离子在氧化膜中的扩散能力,使复合材料的阻抗提升5.3％,腐蚀电流密度下降28.2％,有效地提升了铜基复合材料的耐腐蚀性能.铜基石墨烯复合材料的石墨烯最佳添加量为0.5 wt.％.%Graphene-reinforced copper matrix (G/Cu) composites were prepared by temperature-programmed sintering of their mixtures in molds under pressure.The effects of graphene content on the microstructure,and electrical,thermal,mechanical and corrosion properties of the G/Cu composites were investigated.Results show that the hardness,tensile strength,yield strength,thermal and electrical conductivities,and corrosion resistance of the composites all reached maxima at a graphene content of 0.5 wt.％.The addition of graphene increased the thermal and electrical conductivities,tensile and yield strengths,and hardness of the composites,but led to defect formation in the graphene due to the thermal expansion mismatch between graphene and copper.Therefore,an optimal graphene content was needed to obtain the best improvement of these properties.Tafel and electrochemical impedance tests using the composite as the working electrode,Pt as the counter electrode and a saturated calomel electrode as a reference electrode showed that the composite with a graphene content of 0.5 wt％ had the lowest corrosion current of 3.45× 10-6 μA/cm2 and the highest charge transfer resistance of 1 705 Ω·cm2.