电接触用石墨烯（石墨）-银基复合材料的制备及摩擦磨损性能研究

发布时间：2018-02-21 22:23

本文关键词： 石墨烯石墨银基复合材料钐摩擦磨损　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文采用粉末冶金的方法制备了石墨烯-银基复合材料、二硫化钼-银基复合材料以及添加钐的石墨-银基复合材料,利用显微分析手段对银基材料的组织及摩擦磨损后的表面形貌进行了分析,同时分析了石墨烯、二硫化钼及添加钐元素对银基复合材料物理力学性能(静态)性能的影响,实际模拟了复合材料在通电以及不通电条件下的摩擦磨损试验,研究其在不同电流密度条件下的摩擦磨损性能。为改善复合材料在通电状态及大电流条件下的摩擦磨损能力,本文在传统的石墨-银基复合材料中,添加钐(Sm)用以改善复合材料的性能,随着钐(氧化物)添加量的增加,虽复合材料的硬度和抗弯强度有升高,但会使电阻率增大,因此,本文中钐(氧化物)添加量控制在3wt%以下。在摩擦磨损试验中,添加钐的石墨-银基复合材料能显著提升材料的耐磨性,改善复合材料的抗电耐磨性能,使复合材料的磨损量减小。本文研究中用石墨烯取代石墨,采用粉末冶金的方法制备了石墨烯-银基复合材料,在碳质量分数相同的条件下进行性能比较,当碳含量较低时(6wt%),石墨烯-银基复合材料的各项静态性能优于石墨-银基复合材料,随石墨烯取代量的增加,复合材料的静态性能开始降低。在摩擦磨损实验中,随着石墨烯取代量的增加(6wt%,8wt%,10wt%),复合材料耐磨性能则趋于降低。由于二硫化钼也是一种常用的固体润滑剂,在航空航天自润滑材料中得到广泛应用,本文利用二硫化钼取代石墨,制备了二硫化钼-银基复合材料。研究了二硫化钼含量对复合材料的导电性及强度的影响,并与同质量百分比的石墨-银基复合材料性能进行对比。最后模仿银基复合材料电刷的工况条件,在自制的通电摩擦磨损机上对以上三组成分的复合材料进行了摩擦磨损试验。在电流密度一定的条件下,复合材料的耐磨性的高低依次为添加钐的石墨(6wt%)-银基复合材料、石墨烯(6wt%)银基复合材料、石墨(6wt%)-银基复合材料;提高电流密度,复合材料的磨损量均增加,但耐磨性的排列次序不变,且正刷的磨损量大于负刷。研究结果表明,在传统的石墨-银基复合材料中添加钐,能够有效改善复合材料的导电性、硬度、强度,提高材料的耐摩擦磨损性能及电接触性能等综合性能指标。用石墨烯取代石墨-银基复合材料中的石墨,只有在含量较低时性能改善效果明显,使石墨烯-银基复合材料的静态性能及摩擦磨损性能均优于石墨-银基复合材料。用二硫化钼取代石墨-银基复合材料中的石墨,复合材料的静态性能(硬度、强度、导电性)改善没有明显的优势,而在大气条件下,二硫化钼-银基复合材料的摩擦磨损性能比石墨-银基复合材料差。
[Abstract]:In this paper, graphene silver matrix composites, molybdenum disulfide silver matrix composites and graphite silver matrix composites with samarium were prepared by powder metallurgy. The microstructure and surface morphology of silver based composites after friction and wear were analyzed by means of microanalysis. The effects of graphene, molybdenum disulfide and samarium addition on the physical and mechanical properties (static) of silver based composites were also analyzed. In order to improve the friction and wear ability of the composites under the condition of current and high current, the friction and wear tests of the composites under the condition of electrification and non-electrification are simulated in practice, and the friction and wear properties of the composites under different current density are studied. In this paper, samarium smm is added to the traditional graphite-silver matrix composites to improve the properties of the composites. With the increase of the amount of samarium (oxide), the hardness and flexural strength of the composites increase, but the resistivity increases. In this paper, the content of samarium (oxide) is controlled below 3wt%. In the friction and wear test, the graphite / silver matrix composites with samarium can significantly improve the wear resistance of the composites and improve the electrical wear resistance of the composites. In this paper, graphene was substituted for graphite, and graphene silver matrix composites were prepared by powder metallurgy. The properties of the composites were compared under the same carbon mass fraction. When the carbon content is low, the static properties of graphene / silver matrix composites are better than those of graphite silver matrix composites, and the static properties of the composites begin to decrease with the increase of graphene substitution. With the increase of the substitution amount of graphene, the wear resistance of the composites tends to decrease. As molybdenum disulfide is also a common solid lubricant and is widely used in aerospace self-lubricating materials, the graphite is replaced by molybdenum disulfide in this paper. The molybdenum disulfide silver matrix composites were prepared. The effect of molybdenum disulfide content on the electrical conductivity and strength of the composites was studied. And compared with the graphite-silver matrix composites with the same mass percentage. Finally, the operating conditions of the silver matrix composite brushes were simulated. The friction and wear tests of the composites with the above three components were carried out on a self-made electric friction and wear machine. Under the condition of constant current density, the wear resistance of the composites was in the order of graphite with samarium for 6 wt- silver matrix composites. When the current density is increased, the wear capacity of the composites increases, but the order of wear resistance is constant, and the wear amount of the positive brushes is larger than that of the negative brushes. Adding samarium to the traditional graphite-silver matrix composites can effectively improve the electrical conductivity, hardness and strength of the composites. The friction and wear resistance and electrical contact properties of the composites were improved by using graphene to replace the graphite in the graphite-silver matrix composites, only when the content of graphene was low, the performance of graphite was improved obviously. The static properties and friction and wear properties of graphene silver matrix composites are better than those of graphite silver matrix composites. The static properties (hardness, strength, strength) of graphite silver matrix composites are replaced by molybdenum disulfide. Under atmospheric conditions, the friction and wear properties of molybdenum disulfide silver matrix composites are worse than that of graphite silver matrix composites.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TQ127.11

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