碳纳米管、氧化铝颗粒协同增强铜基复合材料及表面涂层

发布时间：2018-11-14 09:45

【摘要】：金属铜具有优良的导电、导热性能,同时具有良好的延展性,易加工。由于铜在电磁炮轨道用材料、汽车轴承、活塞杆等应用方面,要求其具有较高的力学性能、减摩润滑性能等。因此,本文采用具有优异性能的碳纳米管(CNTs)、耐磨氧化铝颗粒(Al2O3)作为增强相,制备铜基复合材料。希望充分发挥碳纳米管、氧化铝和铜自身优良的性能,并通过碳纳米管与氧化铝的协同作用,制备出具有优异性能的新型铜基复合材料。采用化学镀铜工艺,在碳纳米管、氧化铝颗粒表面包覆铜,改善增强相与基体的润湿性,使其在基体中均匀分布。研究了不同含量增强相、不同的制备工艺对铜基复合材料的力学性能和物理性能的影响,为碳纳米管和氧化铝颗粒协同机制提供实验数据并奠定理论基础。同时加入CNTs和A1203后,铜基复合材料在力学性能、摩擦性能、导电性和导热性方面均体现了协同作用。复合材料的维氏硬度提高了67.2%,协同增加幅度为0.3%；抗拉强度增加了63.8%,协同增加幅度为18.8%；磨损率减小了55.9%,协同幅度为35.0%；导电率保持了76.3%,协同增加幅度为15.8%；热导率保持了76.4%,协同幅度为3.2%。为了使铜基复合材料满足需求并具有较长的使用寿命,本文采用了超音速火焰喷涂工艺在基体表面喷涂WC-12Co涂层。测试了涂层性能：涂层表面硬度比涂层截面硬度高。涂层与基体结合处硬度为311.80HVo.05,比基体硬度高；涂层与基体结合强度为60-70MPa；经历46次热循环后,涂层没有失效；涂层磨损率为10-14-10-13m2.N-1数量级,远低于基体。得到了最适用于涂层的条件为转速300-500r·min-1,载荷2-3N。涂层摩擦方式为粘着磨损和磨粒磨损。涂层磨损率随转速的增大,先减小后增大。随载荷的增大而增大：摩擦系数随转速的增大,先增大后减小。导电率平均值为2.69%IACS,孔隙率为2.8%。
[Abstract]:Metal copper has excellent conductivity, thermal conductivity, and good ductility, easy processing. Copper is required to have high mechanical properties and antifriction lubricating properties in the applications of electromagnetic gun track materials, automobile bearings, piston rods and so on. Therefore, carbon nanotubes (CNTs) (CNTs), wear-resistant alumina particles (Al2O3) were used as reinforcement phase to prepare copper matrix composites. We hope to give full play to the excellent properties of carbon nanotubes, alumina and copper, and through the synergistic effect of carbon nanotubes and alumina, a new type of copper matrix composites with excellent properties can be prepared. Copper was coated on the surface of carbon nanotubes (CNTs) and alumina particles by electroless copper plating to improve the wettability of the reinforced phase and the matrix and make it distribute uniformly in the matrix. The effects of different contents of reinforcing phases and different preparation processes on the mechanical and physical properties of copper matrix composites were studied. The experimental data and theoretical foundation were provided for the synergistic mechanism of carbon nanotubes and alumina particles. After the addition of CNTs and A1203, the synergistic effects of mechanical properties, friction properties, electrical conductivity and thermal conductivity of copper matrix composites were observed. The Vickers hardness of the composite increased by 67.2, the synergistic increase was 0.3, the tensile strength increased 63.8and the synergistic increase was 18.8. the wear rate decreased 55.9 and the synergism was 35.0. The conductivity kept 76.3and the synergistic increase was 15.8.The thermal conductivity kept 76.4and the synergistic amplitude was 3.2. In order to make the copper matrix composites meet the demand and have a long service life, the supersonic flame spraying process was used to spray the WC-12Co coating on the substrate surface in this paper. The hardness of coating surface is higher than that of coating cross section. The hardness of the coating is 311.80HVo.05which is higher than that of the substrate, the bonding strength between the coating and the substrate is 60-70MPa, and the coating has no failure after 46 thermal cycles. The wear rate of the coating is of the order of 10-14-10-13m2.N-1, which is much lower than that of the substrate. The optimum conditions for coating were obtained as follows: rotational speed 300-500r min-1, load 2-3N. The wear mode of coating is adhesive wear and abrasive wear. The wear rate of the coating decreases first and then increases with the increase of rotational speed. With the increase of load, the friction coefficient increases first and then decreases with the increase of rotational speed. The average conductivity is 2.69 and the porosity is 2.8.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB333;TB383.1

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