干摩擦条件下混杂增强聚醚醚酮复合材料摩擦学性能研究

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	干摩擦条件下混杂增强聚醚醚酮复合材料摩擦学性能研究
	马娜
学位类型	硕士
导师	隋国鑫
	2011
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	混杂增强聚醚醚酮复合材料碳纤维钛酸钾晶须摩擦学性能 Hybrid Reinforced Peek Composite Carbon Fiber (Cf) Potassium Titanate Whiskers (Ptw) Tribology
摘要	"聚醚醚酮（PEEK）是综合性能十分优异的特种工程塑料。作为结构材料使用时具有很高的比强度和比刚度。而作为耐磨材料，PEEK的摩擦系数低，耐磨性能良好，能在较广的压力、速度、温度和接触面粗糙度范围内保持卓越的耐磨损性能。但是纯PEEK在某些摩擦应用情况下还存在摩擦系数较大，不宜在高速摩擦环境下使用等缺点。为了使PEEK获得更加优异的摩擦学性能，通常采用加入填料进行复合的方法。在一些情况下，微纳米填料的加入可进一步提高碳纤维增强复合材料的摩擦学性能，短碳纤维和微纳米填料在复合材料的摩擦过程中表现出一定的协同作用，使材料的耐磨性能得到很大提高。目前对于短碳纤维和晶须混杂增强复合材料的干摩擦学性能报道仍然较少，因此有必要对其进行研究。本论文主要采用双螺杆挤出机熔融共混和注塑成型的方法制备短碳纤维（CF）、钛酸钾晶须（PTW）、聚四氟乙烯（PTFE）及石墨混杂增强聚醚醚酮复合材料（PEEK/CF/PTW），并系统的研究了该复合材料的摩擦学性能。由于材料力学及热学性能与材料的摩擦学性能有密切关系，对材料的力学及热学性能也进行了考察。结果表明：PEEK/CF/PTW混杂增强复合材料具有优异的力学性能，能够保证其在苛刻条件下的使用。碳纤维和钛酸钾晶须对PEEK基体均能起到有效的增强作用，其中碳纤维是复合材料力学性能提高的关键因素。而纤维和晶须的加入对材料玻璃化转变温度、结晶度和熔点等热学性能影响不大。研究发现：碳纤维和钛酸钾晶须对材料摩擦学性能均具有很好的增强作用，碳纤维作为PEEK/CF/PTW混杂增强复合材料在摩擦过程中的主要承载相，其状态对复合材料的摩擦学性能有十分重要的影响，在本研究中，碳纤维在摩擦过程中主要表现为减薄和破损。钛酸钾晶须的加入可以有效地减轻碳纤维上的应力集中；在摩擦过程中可在一定程度上避免碳纤维对对摩金属面的剧烈切削作用；实现对材料的微观增强，同时，摩擦过程中被碾碎的钛酸钾晶须可以有效保护碳纤维免于破坏。正是由于纤维和晶须之间的协同作用，使PEEK/CF/PTW混杂增强复合材料拥有比PEEK/CF和PEEK/PTW复合材料更加优异的耐磨性能和良好的稳定性，能适应在较为苛刻的条件下服役。对摩擦过程中载荷和填料含量对PEEK/CF/PTW混杂增强复合材料摩擦学性能的影响进行了研究。结果表明：不同组分复合材料的摩擦系数和磨损率随载荷的变化趋势基本分成随载荷增加持续下降和先下降后上升两种；填料含量对混杂增强复合材料的摩擦学性能有十分重要的影响，碳纤维在低载荷条件下能更好的展现其对聚合物基体摩擦学性能的增强作用。钛酸钾晶须含量较低的复合材料在高载荷下表现出了良好的耐磨性能，而晶须含量较高的材料在低载荷下具有较低磨损率。"
其他摘要	"Polyetheretherketone (PEEK) is a special engineering plastic with excellent properties. As a structural material, PEEK has high specific strength and high specific stiffness. As a wear resistant material, PEEK has low friction coefficient and low wear rate, which makes it possess excellent wear resistance at a wide range of pressure, velocity, temperature and roughness. However, during the friction in some case, pure PEEK usually has high friction coefficient and can not be used at high velocity. Fillers are usually added to improve the tribological properties of PEEK. In some cases, the addition of some inorganic particles cloud improve the tribological properties of short fibers reinforcing composites. There are synergetical effects between the fillers, which could improve the wear resistance of the materials. But the hybrid reinforcement of short carbon fibers and whiskers is few investigated by now. It is necessary to study on it systemically. PEEK composites reinforced by short carbon fibers (CF), potassium titanate whiskers (PTW), polytetrafluoroethylene (PTFE) and graphite were prepared using twin-screw extrusion compounding and injection molding. The tribological properties of PEEK composites were systemically studied. Since there is a close relationship between the mechanical, thermal and tribological properties of materials, the mechanical properties and thermal properties of PEEK compsites were also studied. The results showed that hybrid reinforced PEEK composites had excellent mechanical property, which made them apply in severe conditions. Both CF and PTW could reinforce the matrix effectively. CF was the key to improving the mechanical properties of the composites. However, the effects of CF and PTW on the thermal properties of the composites such as the temperature of glass-transition, the degree of crstallinity and the melting point were not obvious. In this research, both CF and PTW could improve the tribological properties of PEEK composites. CF borne most loads during the sliding to protect PEEK matrix from severe abrasion, so the morphology of CF was important to the tribological properties of the composites. Fiber thinning and broken could be seen in this work. PTW could reduce the stress concentration on CF by increasing the stiffness of the composites to protect CF from failure and could reduce the cutting between CF and counterparts during the sliding. Moreover, the mechanical properties of the matrix between the CF would be improved by the reinforcement of PTW. The small parts falled from PTW during sliding would protect CF during the sliding. PEEK/CF/PTW composites showed more excellent tribological properties and better stability in dry sliding than PEEK/CF and PEEK/PTW composites resulted from the synergistic effect between CF and PTW and could facilitate in more application conditions. The effects of the load and the filler content on the wear behaviors of the hybrid composites were also discussed. The results showed that for most composites in this work, the friction coefficients and wear rates decreased or decreased first and then increased with the load rising. Fillers contents had great effect on the tribological behaviors of the composites. The composites with higher CF content showed outstanding tribological performances at low load. High PTW loading composites presented a lower wear rate at low load. At high loads, the composites with lower PTW contents had better wear resistance."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64392
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	马娜. 干摩擦条件下混杂增强聚醚醚酮复合材料摩擦学性能研究[D]. 北京. 中国科学院金属研究所,2011.