【作者】 唐雷；

【导师】 崔振铎；

【作者基本信息】 天津大学 ， 材料学， 2010， 硕士

【摘要】 本文选用镀铜纳米SiC颗粒和纳米碳洋葱颗粒,采用粉末冶金的办法制备了Cu/Nano-SiC复合材料和Cu/Nano-SiC+纳米碳洋葱自润滑复合材料。系统研究了纳米SiC颗粒表面镀铜、以及添加纳米碳洋葱对铜基复合材料物理性能、力学性能和耐磨性能的影响,并对其耐磨机理作了初步探究。采用化学镀可以在纳米SiC表面成功涂覆致密的铜镀层,之后利用粉末冶金以及复压复烧工艺制备了纳米SiC弥散强化铜基复合材料,之后通过添加固体润滑剂-碳洋葱制备出了Cu/Nano-SiC+纳米碳洋葱自润滑复合材料材料。分析了Nano-SiC颗粒表面修饰铜对复合材料界面结合及其性能的影响,以及纳米碳洋葱的添加对复合材料性能的影响。研究表明:采用复压复烧工艺能有效提高复合材料各项性能,纳米SiC表面镀铜能有效改善界面结合状况,进一步提高了复合材料的密度、硬度和抗弯强度,但导电性能随着增强体的加入而减弱。研究了不同载荷下复合材料的摩擦磨损性能,通过SEM、EDS等分析手段对表面磨痕及其成分的变化情况进行了分析,探讨了Cu/SiC复合材料和Cu/SiC+纳米碳洋葱自润滑复合材料的磨损机理。结果表明:纳米SiC表面化学镀铜处理可以改善Cu/SiC复合材料的磨损性能。低载荷时磨损机制是以粘着磨损为主;高载荷时则以磨粒磨损为主。Cu/SiC+纳米碳洋葱复合材料的磨损研究表明:碳洋葱可有效提高复合材料的耐磨损性能,低载荷时,在磨损表面形成了一层氧化物和碳洋葱润滑层,可降低材料磨损率,磨损界面的高温造成的氧化磨损是此时的主要磨损机制;高载荷时,由于润滑层被破坏,而碳洋葱不能得到有效补充,引起磨损率升高,磨损机制为:碳洋葱低含量时以磨粒磨损为主;高含量时以粘着磨损为主,同时伴有氧化磨损,但是随着碳洋葱的增加,破坏程度得到缓解,磨损率总体趋势逐渐降低。更多还原

【Abstract】 In this paper, Cu/Nano-SiC and Cu/Nano-SiC+Nano-carbon-onions composites were prepared by powder metallurgy approach with SiC coated by copper. The mechanism of the electroless copper was systematically studied. The mechanical properties of the composites were also tested and analyzed. In addition, the wear behaviors and the wear mechanisms of the composites were initially investigated.The Nano-SiC particles were successfully coated with a uniform and compact layer of copper by electroless plating which is simple、feasible and convenient approach. After that, the Cu/Nano-SiC composite and Cu/Nano-SiC+Nano-carbon onions composites were prepared by powder metallurgy and repressing and resintering technique. The influences of Cu-coated SiC on interfacial combination and the properties of composites were analyzed. Besides, the influence of different content of Nano-carbon onions on properties of composites was also studied. The research showed that: repressing and resintering were conducive to properties of composites. Cu-coated SiC resulted in the increase of density、bending strength and hardness of the composites. But the electrical conductivity of the composites with the increase of the reinforcement content gradually weakened.After the friction and wear tested under the different loading conditions, the worn surfaces and the regularity for change of compositions and morphologies were studied by SEM and EDS. And the wear behaviors and mechanisms of two composites were systematically investigated.We found that the wear experiment of Cu/Nano-SiC composite showed that the wear-resisting properties were improved because of Nano-SiC by eletrocless copper. The wear mechanism of composites was mainly adhesive wear at low load; but high load, it was mainly abrasive wear.Furthermore, we found that: it could effectively improve the wear resistance of the composites by adding Nano-carbon onions. At low load, a lubricating layer of oxide and carbon onion was formed on the wear surface, which could effectively reduce the wear rate. At this time, the main wear mechanism was the oxidation wear because of high temperature of the surface lubricating layer. At high load, the lubricating layer was destroyed. At this time, the Nano-carbon onions could not be complemented effectively, which could increase of the wear rate. Because of that, the wear mechanism comply with following tendency-the mainly wear mechanism at low contentof carbon onions was the abrasion; while at high content it was the adhesive, accompanied by oxidation wear. But with the increasement of the carbon onions, the overall wear rates decreased gradually.更多还原