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Polypropylene/thermoplastic polyurethane (PP/TPU) blends of different weight ratios (75/25 and 25/75) were processed by melt blending using a maleic anhydride–grafted polypropylene (PP-g-MA) copolymer as coupling agent. The influence of the amount of the coupling agent (0, 3, 5, 7, 9, 11 phr) on the mechanical, frictional, and wear properties of the blends were characterized through tensile test, three-point bending, dynamic mechanical analysis (DMA), and ball-on-disc wear tests. PP-g-MA was found to be an effective compatibilizer for PP/TPU blends, and mechanical and wear properties of the blends were proved to be strongly impacted by the amount of coupling agent. Tensile strength of the blends tends to increase with increasing the PP-g-MA content and 9 phr is found to be optimal for both concentrations of the blends. Good miscibility of the blends with increasing compatibilizer content was also verified by DMA. From the wear test results, the compatibilizer was found to be more effective in PP75/TPU25 blends, in parallel with the results of the mechanical tests. The PP75/TPU25 blend with 11 phr PP-g-MA content was superior to the other blends. In addition, in this work, a new model based on image processing is proposed that provides accurate and fast wear rate measurement and detailed information of the wear track, especially in heterogeneous materials. Using the model, the homogeneity of the wear track widths was proved to be strongly impacted and improved by the use of a coupling agent. 相似文献
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ABSTRACTIn this article, brake discs are exposed to high thermal stress, causing thermal fatigue damage. The aim of this work is to study the evolution of the wear behavior of brake disc materials, such as cast iron, chromium steel, and metal matrix composites, under the influence of thermal fatigue. The brake disc specimens are heated and then cooled rapidly. Then, wear tests are carried out using a pin-on-disc-type tribometer. Organic and semimetallic friction materials are used for all wear tests. The results show that thermal fatigue affects the structure of the contact surfaces of all of the disc specimens by increasing their roughness. Furthermore, the wear rate of the friction materials increased, except a reduction of the wear rate is noted for the semimetallic friction material rubbing against cast iron. Moreover, thermal fatigue has no significant influence on the coefficient of friction. The worn surface of the metal matrix composite sliding against semimetallic friction material is characterized by abrasive and adhesive wear mechanisms. 相似文献
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While the use of ORNL developed high-thermal-conductivity graphitic foam materials has been focused on thermal management applications, recent experiments have revealed their potential as bearing surfaces as well. The three primary tribological advantages are: (1) they can efficiently remove frictional heat, (2) their natural porosity can trap wear debris, and (3) their porosity can serve as a lubricant reservoir for the contact surface. A series of pin-on-disk experiments were conducted at both room temperature and 400 °C to compare the sliding friction and wear characteristics of the densified graphitic foam (mated against M-50 tool steel or against alumina) to those of conventional bearing materials like graphite, bearing bronze, poly- tetrafluoroethylene, bearing steel, and a Co-based superalloy. At room temperature and under low contact pressure, the tribological behavior of the densified graphitic foam material was comparable to that of graphite and better than that of other bearing materials. At 400 °C, traditional graphite exhibited a dusting wear regime accompanied by a high friction coefficient. In contrast, the graphitic foam demonstrated an ability to maintain low friction and wear at that temperature. 相似文献
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对MPX-2000盘销式摩擦磨损试验机进行改装,增添了加热及相应的控制和冷却系统。改装工作未对原试验机零件进行再加工而只添加了部分零件,从而使改装后的试验机很容易恢复原状并保证精度。改装的试验机数据最大偏差小于5%,可用于800℃以下的摩擦磨损试验,温度偏差小于2.5%。 相似文献
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对20%Vol SiCp/AI复合材料与有机摩擦材料组成的摩擦副的摩擦磨损特性进行了试验研究.试验表明:该摩擦副在不同的速度情况下都具有平稳的摩擦系数.摩擦系数在一定速度范围内随速度增加而减小,而在超过一定速度后随速度增加而增大.对摩擦系数随速度变化的机理进行了讨论. 相似文献
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采用双-[γ-(三乙氧基硅基)丙基]四硫化物(Si69)和乙烯基三乙氧基硅烷(A151)对PAN基碳纤维(CF)进行表面改性处理,利用SEM、FTIR、EDX对改性前后的CF进行表征,测量接触角和表面能、力学性能和界面性能;通过湿法成形技术,制备不同改性CF增强聚酰亚胺纸基摩擦材料,并测试其孔隙率和摩擦学性能。结果表明:与未改性CF相比,Si69和A151能够有效地增加CF表面粗糙度,且新基团的引入使接触角变小,提高了CF表面活性,改善了纤维与树脂之间的结合力,使得A151-CF表面能增加了37.3%,Si69-CF表面能增加了109.4%,A151-CF/聚酰亚胺复合材料界面性能增加了19.1%,Si69-CF/聚酰亚胺复合材料界面性能提高了45.3%;相比未改性CF,Si69改性CF使纸基摩擦材料孔隙率下降了20.2%,A151改性CF使纸基摩擦材料孔隙率下降了8.8%;表面改性CF能够提高纸基摩擦材料的摩擦学性能,其中Si69改性CF增强纸基摩擦材料摩擦学性能优于A151改性CF增强纸基摩擦材料。 相似文献
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为探究船舶艉轴机械密封用高分子材料在实际工作环境下的摩擦磨损性能,选用浇注型聚氨酯弹性体(CPU)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二酯(PBT)、玻璃纤维改性聚己二酰丁二胺复合材料(GF/PA46)与玻璃纤维改性聚四氟乙烯复合材料(GF/PTFE)5种材料,在载荷为0.5 MPa,线速度为7 m/s的工况下开展摩擦磨损性能测试。结果表明:重载、高速的工况使得CPU、PET、PBT、GF/PA46材料出现了不同程度的剥落与犁沟,摩擦因数与磨损量较大;GF/PTFE材料仅出现一些相对轻微的撕裂和磨痕,相较于CPU、PET、PBT、GF/PA46材料,GF/PTFE的平均摩擦因数分别下降了66.6%、80.4%、86.1%、87.8%,单位时间磨损量分别下降了91.7%、92.7%、88.6%、97.0%,摩擦磨损性能最优。 相似文献
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机械密封摩擦特性影响因素分析 总被引:4,自引:0,他引:4
机械密封的摩擦状态决定了密封性能的好坏.本文综合分析了摩擦系数及摩擦特性准数等因素对摩擦特性的影响,为机械密封的设计和摩擦状态分析提供了参考依据. 相似文献
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以FeS和CuSn8Ni1粉末为原料,利用机械合金化技术和粉末冶金技术制备了FeS/Cu复合材料,探讨了不同载荷情况下所制备的FeS/Cu复合材料的摩擦学性能及润滑膜与转移膜特征。结果表明:机械合金化提高了FeS与铜合金基体界面结合性能,进而提高了材料减摩耐磨性能;当载荷较小时,摩擦副表面接触不稳定,复合转移膜不连续,摩擦因数波动大;载荷较大时,复合转移膜易破损,材料的减摩耐磨性能变差;当载荷为150 N时,载荷适宜,材料表面软化,复合转移膜更加完整,摩擦因数较小。 相似文献
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用MPV 2 0 0型摩擦磨损试验机对超高分子量聚乙烯 (UHMW PE)塑料合金轴承在水润滑介质不同含沙量的条件下进行了摩擦学性能测定 ,分别考察了载荷、速度以及运行时间等对合金轴承摩擦学性能的影响。为水润滑合金轴承的实际应用提供理论指导。 相似文献
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本文研究了用机械合金化方法制备出Si3N4/Fe基纳米晶复合粉末,用常规粉末冶金工艺烧结出试样,测试了复合材料的常温摩擦磨损性能,并对其显微组织进行了分析,认为纳米晶的界面确实机改善Si3N4与Fe的结合强度。 相似文献