Effect of Carbon Nanotube Addition on Tribological Behavior of UHMWPE

Carbon nanotubes (CNTs) were added to Ultra-high molecular weight polyethylene (UHMWPE) to improve the tribological properties of UHMWPE. CNTs which have a diameter of about 10–50 nm, while their length is about 3–5 nm were produced by the catalytic decomposition of acetylene gas using a tube furnace. Ball-on-disc-type wear tests were performed to evaluate the tribological performance of UHMWPE composites reinforced with CNTs. The results showed that addition of carbon nanotube up to 0.5 wt% lowered wear loss significantly and increased friction coefficient slightly. Also through the scanning electron microscope (SEM), the surfaces of UHMWPE were observed and analyzed to discuss the tribological behavior of CNT added UHMWPE.     

UHMWPE与橡胶共混水润滑轴承摩擦磨损性能试验研究

为改善丁腈橡胶水润滑轴承的摩擦学性能，以丁腈橡胶为基体，通过添加不同量的超高分子量聚乙烯（UHMWPE）粉末（分别为丁腈橡胶量的12%、50%、100%）制得3种复合材料；分析不同复合材料的结构，研究其在水润滑条件下的摩擦磨损特性，并与纯丁腈橡胶和纯UHMWPE材料进行对比。结果表明：制备的UHMWPE与丁腈橡胶复合材料中，UHMWPE以分散相的形式分布在丁腈橡胶基体中，分布较为均匀；UHMWPE的加入提高了丁腈橡胶材料的自润滑性能，其中UHMWPE的添加量为丁腈橡胶的50%和100%时复合材料在低速时的摩擦因数明显减小；UHMWPE的加入提高了丁腈橡胶基体的硬度，改善了复合材料摩擦表面的挤压变形，使得复合材料的磨损量有所降低。研究表明，一定添加量的UHMWPE添加量可明显改善丁腈橡胶水润滑轴承的摩擦学性能，其最佳添加量为丁腈橡胶的50%。     

UHMWPE基水润滑轴承摩擦及润滑特性的试验研究

针对纤维填料改性UHMWPE水润滑轴承的摩擦磨损性能进行研究。在平面摩擦磨损试验机上对玻璃纤维及碳纤维填料对UHMWPE复合材料摩擦性能进行试验,并分析GF-CF-UHMWPE材料与Thordon SXL材料在干摩擦、水润滑工况下的摩擦因数及磨损量。最后,采用径向水润滑轴承试验台对比研究了GF-CF-UHMWPE轴承和Thordon SXL轴承在不同载荷下摩擦因数随转速的变化规律。结果表明:纤维填料能显著增强UHMWPE的减摩性和耐磨性,GF-CF-UHMWPE材料具有更好的耐温性能,线性热膨胀系数也显著减小;GF-CF-UHMWPE轴承具有相同载荷下启动转速低,启动摩擦因数小的特性。     

硫酸钙晶须填充UHMWPE复合材料的摩擦磨损性能

以硫酸钙晶须(CSW)作为填料填充改性超高分子量聚乙烯(UHMWPE),采用热压成型法制备了不同硫酸钙晶须含量的UHMWPE/CSW复合材料;在销-盘摩擦磨损试验机上考察了硫酸钙晶须对UHMWPE/CSW复合材料摩擦学性能的影响,利用扫描电子显微镜对UHMWPE复合材料的磨损表面进行了微观分析。结果表明:随着硫酸钙晶须填充量的增加,复合材料的硬度逐渐增大,耐磨性能逐渐增加,摩擦因数逐渐减小;当硫酸钙晶须填充质量分数为20%时,UHMWPE/CSW复合材料的摩擦学性能最好。     

Comparative study of micro- and nano-ZnO reinforced UHMWPE composites under dry sliding wear

This is a comparative study between ultra-high molecular weight polyethylene (UHMWPE) reinforced with micro-zinc oxide (ZnO) and nano-ZnO under different filler loads. These composites were subjected to dry sliding wear test under abrasive conditions. The micro- and nano-ZnO/UHMWPE composites were prepared by using a hot compression mould. The wear and friction behaviours were monitored using a pin-on-disc (POD) test rig. The pin-shaped samples were slid against 400 grit SiC abrasive papers, which were pasted, on the stainless steel disc under dry sliding conditions. The worn surfaces and transfer film formed were observed under the scanning electron microscope (SEM). Experimental results showed that UHMWPE reinforced with micro- and nano-ZnO would improve the wear behaviour. The average coefficient of friction (COF) for both micro- and nano-ZnO/UHMWPE composites were comparable to pure UHMWPE. The weight loss due to wear for nano-ZnO/UHMWPE composites are lower compared to micro-ZnO/UHMWPE and pure UHMWPE. The optimum filler loading of nano-ZnO/UHMWPE composites is found to be at 10 wt%. The worn surface of ZnO/UHMWPE composites shows the wear mechanisms of abrasive and adhesive wear. Upon reinforcement with micro- and nano-ZnO, the abrasive and adhesive wear of worn surfaces transited from rough to smooth.     

填充纳米SiO2对超高分子量聚乙烯复合材料摩擦磨损性能的影响

用热压成型法制备了纳米SiO2填充超高分子量聚乙烯(UHMWPE)复合材料,采用销-盘式摩擦磨损试验机考察了纳米粒子对复合材料摩擦磨损性能的影响,采用扫描电子显微镜观察了复合材料磨损表面形貌,并借助X射线能谱仪对试样磨损表面进行了微区分析。结果表明:纯UHMWPE磨损表面局部存在着大量的粘着变形和疲劳裂纹的特征,填充15%(质量分数)的纳米SiO2能较好地改善UHMWPE/nano-SiO2复合材料的摩擦磨损性能,其磨损表面只存在粘着撕裂现象,看不到疲劳裂纹特征。当填充纳米SiO2质量分数达到20%时,其磨损表面存在贫Si区和富Si区,同时磨损表面呈现出热裂纹迹象,复合材料的耐磨性能改善程度明显下降,并且摩擦因数出现了增大趋势。     

聚丙烯、炭黑和碳纤维共混填充超高分子量聚乙烯复合材料的力学和摩擦磨损性能

采用模压成型的方式制备超高分子量聚乙烯(UHMWPE)复合材料,通过AG-1型电子万能实验机和MM-200型摩擦磨损试验机分别研究填料对复合材料力学性能和摩擦磨损性能的影响,采用光学显微镜分析复合材料磨损表面的形貌。结果表明:聚丙烯(PP)和无机填料炭黑(CB)或CB与碳纤维(CF)混杂填料的加入使UHMWPE复合材料的拉伸强度降低,弯曲模量和硬度增加,其中UHMWPE/PP/CB/CF复合材料的弯曲模量和硬度增幅大于UHM-WPE/PP/CB复合材料。填料的加入可改善UHMWPE复合材料的摩擦磨损性能,当填料的质量分数为5%时,UHMWPE复合材料的摩擦磨损性能最好,且UHMWPE/PP/CB/CF复合材料的耐磨性能优于UHMWPE/PP/CB复合材料。与UHM-WPE相比,UHMWPE/PP/CB/CF复合材料的摩擦因数和磨痕宽度分别下降了10%和44%,UHMWPE/PP/CB复合材料则分别下降了12%和42%。光学显微镜观察表明填料的加入大大改善了UHMWPE的磨粒磨损,复合材料表面以较浅的犁沟磨损为主要特征。     

Effect of UHMWPE Microparticles on the Tribological Performances of High-Strength Glass Fabric/Phenolic Laminate Composites Under Water Lubrication

The tribological behaviors of ultra-high molecular weight polyethylene (UHMWPE) microparticle-modified high-strength glass fabric/phenolic laminate composites sliding against stainless steel under water lubrication have been investigated. Results showed that the incorporation of UHMWPE microparticles, especially at the mass fraction of 5.0 %, improved the wear resistance of the laminate composite to a significant extent, because UHMWPE microparticle can effectively absorb and dissipate the friction energy through a plastic deformation during the formation of the regular ripple-like abrasion patterns on its worn surface. During the sliding process, after the phenolic resin was firstly worn off, UHMWPE microparticles with much better wear resistance were protruded from the worn surface of the laminate composite, leading to a fundamental change in the contact status of the matched surfaces from rigid resin and fibers/steel to flexible UHMWPE/steel. As a result, low and steady friction coefficient was obtained due to good adaptability of UHMWPE to water lubrication.     

纳米颗粒TiO2和SiO2对碳纤维/超高分子量聚乙烯复合材料力学和摩擦学性能的影响

采用UMT-5型摩擦磨损试验机和万能材料试验机考察TiO2和SiO2两种纳米颗粒对碳纤维(CF)/超高分子量聚乙烯(UHMWPE)复合材料摩擦学性能和力学性能的影响,利用扫描电镜观察复合材料断面形貌和磨痕表面形貌.结果表明:纳米TiO2和SiO2的加入可以改善碳纤维与树脂之间的界面结合强度,从而改善了 CF/UHMWP...     

玻璃微珠增强PPS复合材料的摩擦性能研究

2种不同粒径的空心玻璃微珠与聚苯硫醚树脂通过熔融共混挤出制得复合材料,研究了这2种玻璃微珠对聚苯硫醚树脂摩擦磨损性能的影响。通过扫描电子显微镜(SEM)对摩擦表面、断面形貌进行了观察和分析。结果表明:经过偶联剂处理的玻璃微珠能够提高PPS的减摩抗磨性能,玻璃微珠粒径越小,所得复合材料的摩擦因数越小;聚合物材料在摩擦过程中形成结合牢固、薄而均匀的转移膜是其发挥摩擦学作用的重要保证,复合材料的磨损机制主要为粘着磨损和疲劳磨损;采用玻璃微珠提高聚苯硫醚树脂的减摩耐磨性能是可行的,而大小均匀、完全规则的球形玻璃微珠粒子将可以更有效地提高复合材料的摩擦性能。     

Y-PSZ/BGC生物陶瓷的纳米力学性能及摩擦学行为研究

合成了生物活性玻璃粉末,采用无压烧结工艺制备了Y-PSZ/BGC复合陶瓷材料。利用纳米硬度分析测试系统(Triboindenter)测定了复合陶瓷的纳米力学性能,用销盘式摩擦磨损试验机考察了血浆润滑条件下复合陶瓷的生物摩擦学性能。结果表明:BGC的加入量在10%~15%(质量分数)范围内,复合陶瓷的纳米力学性能最佳,同超高分子量聚乙烯配副时的摩擦因数和磨损率也最小。磨损表面的N元素波谱分析结果表明,摩擦副表面存在血浆蛋白质的沉积。     

GF/PTFE自润滑纤维复合材料磨损性能热衰退研究

针对高频摆动关节轴承摩擦热对自润滑纤维复合材料摩擦磨损性能的影响,研制了高频使用条件下的玻璃纤维增强聚四氟乙烯(GF/PTFE)自润滑纤维复合材料,利用MYB～500高频高载摆动摩擦磨损试验机,对其进行不同摩擦温度下的摩擦磨损性能测试,研究摩擦热作用下材料自润滑性能和磨损性能衰退特征,分析磨损产物和摩擦表面以及不同摩擦温度下材料的磨损机理。结果表明,摩擦热对材料自润滑性能影响显著,适当的摩擦温度范围能够保证材料的自润滑性能,摩擦温度和摩擦因数之间互为耦合作用,对材料的磨损性能具有一定的影响;高摩擦热作用于自润滑过程及机理的改变,造成材料的磨损性能衰退现象。因此,不同温度下材料的磨损特征具有明显的差异化,其中低摩擦温度下(60～120℃)材料自润滑性能优异,磨损率很低;140℃摩擦温度条件下材料摩擦磨损性能开始衰退;材料在高摩擦温度下(140～180℃)的磨损初期自润滑性能良好、磨损轻微,而中后期磨损严重。微观分析表明,低摩擦温度下材料的磨损机理以轻微粘着和疲劳磨损为主;高摩擦温度下材料的磨损以片状剥落、纤维剪切破坏为主,且磨损面局部损伤特征明显,磨损严重。     

Comparison of tribological behavior of nylon composites filled with zinc oxide particles and whiskers

Mechanical properties and tribological behavior of nylon composites filled with zinc oxides were investigated in this paper. Different effects of ZnO particles and ZnO whiskers filling on the friction and wear behavior of nylon 1010 (PA1010) composites under dry friction condition were observed. The hardness, tensile strength and scratch coefficients of two kinds of nylon composites filled with the ZnO particles and whiskers were measured. Experimental results show that ZnO particles and ZnO whiskers improve the mechanical and tribological properties of nylon composites without affecting the crystallinity of nylon matrix. Hardness, tensile strength and scratch coefficient of composites are increased by the addition of ZnO particles and ZnO whiskers. Filler shape has little effect on the friction coefficients of nylon-based composites. These composites filled with particles and whiskers have nearly the same friction coefficients which locate between 0.4 and 0.45. The wear rates of composites are strongly dependent on filler shape and filler content. Particle-filled composites exhibit the lower wear rates than whisker-filled composites when the content of filler is lower than 10 wt.%. After that, the case is reversed. Ploughing and adhesion are the main wear mechanisms of composites with the addition of both ZnO particles and ZnO whiskers.     

超高分子量聚乙烯/纳米Al2O3复合材料的磨损表面特征分析

用热压成型法制备了纳米氧化铝填充超高分子量聚乙烯(UHMWPE)复合材料,采用销盘式摩擦磨损试验机考察了纳米粒子对复合材料摩擦磨损性能的影响;采用扫描电子显微镜观察了复合材料磨损表面形貌,并借助X射线能谱仪对试样磨损表面进行了微区分析。结果表明:UHMWPE/nano-A l2O3复合材料中的纳米A l2O3粒子含量不同,其磨损表面的碳元素含量也发生不同程度的变化。填充质量分数为15%的纳米A l2O3能较好地改善UHMWPE/nano-A l2O3复合材料的摩擦磨损性能,其磨损表面出现了明显的贫A l区和富A l区,且富A l区以“岛”的形式分布在贫A l区中。     

Friction and sliding wear of UHMWPE modified cotton fibre reinforced polyester composites

Ultrahigh molecular weight polyethylene (UHMWPE) modified polyester-cotton composites were developed and studied for friction and sliding wear behaviour at different applied loads and UHMWPE concentrations. Sliding wear tests were conducted by using pin-on-disc apparatus. Composites in the form of the pin were tested against EN-24 steel disc. The specific wear rate of polyester reduced on reinforcement of cotton and on addition of UHMWPE. The coefficient of friction of polyester resin increased on cotton reinforcement and reduced significantly on addition of UHMWPE in cotton polyester composite. The composites exhibited reductions in specific wear rate against the normal load in the specimens those containing 7.41 or higher volume percent of UHMWPE. The significant reduction in wear rate of UHMWPE modified polyester-cotton composite has been discussed with the help of SEM observations of worn surfaces and coefficient of friction. The addition of 14.19 vol.% UHMWPE in polyester resin brought down the value of μ to nearly half to that of polyester resin and 1/3rd of cotton polyester composite.     

Effect of Blowing Air and Floating Sand-dust Particles on the Friction and Wear Behavior of PTFE, UHMWPE and PI

The friction and wear behaviors of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), and polyimide (PI) have been comparatively evaluated under dry sliding, blowing air, and simulated sand-dust conditions. The tribological tests were conducted on an improved block-on-ring test rig equipped with an attachment for simulating the sand-dust environment. The reason for the difference in the tribological behavior of these polymers under the three test conditions was also comparatively discussed, based on scanning electron microscopic examination of the worn polymer specimens and counterfaces. Under blowing air conditions, the decrease of the contact temperature produced by blowing air led to the increase in the shearing strength of the sliding surface when compared with dry sliding conditions and hence to cause an increase in the friction coefficient and a remarkable decrease in the wear rate of PTFE and UHMWPE. On the contrary, blowing air produced a decrease in the friction coefficient of PI because of the formation of transfer film on the counterfaces, and an increase in the wear rate, because the blowing air considerably promoted the transfer of PI onto the counterfaces when compared with dry sliding conditions. Both PTFE and UHMWPE registered the lowest wear rate under sand-dust conditions, owing to the tribolayer formation on the worn surfaces, while PI exhibited the highest wear rate because no tribolayer was formed during the abrasive wear process.     

纳米SiO_2、玻璃微珠共混改性UHMWPE复合材料空蚀性能研究

通过模压成型工艺制备纳米SiO2、玻璃微珠颗粒共混改性UHMWPE复合材料,采用MRH-5A型环块磨损试验机研究载荷以及玻璃微珠含量对UHMWPE复合材料摩擦磨损性能的影响,利用转盘式空蚀磨损试验装置对复合材料进行空蚀磨损试验。结果表明,适量的纳米SiO2和玻璃微珠颗粒填充可以提高UHMWPE硬度,有效地改善UHMWPE的摩擦磨损性能和抗空蚀性能,质量分数10%纳米SiO2和2%玻璃微珠改性UHMWPE复合材料抗空蚀性能是纯UHM-WPE的3倍。     

Study on Tribological Performance of NiAl Matrix Self-Lubricating Composites Containing Graphene at Different Loads

This study aimed to explore the possibility of improving the tribological performance of NiAl matrix composites by graphene addition. Friction and wear experiments of as-prepared specimens were conducted under different conditions using a pin-on-disk wear testing machine. NiAl matrix composites containing graphene showed satisfactory performance in friction coefficient and wear resistance compared to NiAl matrix composites without graphene. For the active effect of graphene, the friction coefficient and wear rate of NiAl matrix composites were maintained at relatively lower values. The beneficial antifriction and antiwear effects of graphene gradually failed when the applied load was above 8 N. Graphene in NiAl matrix composites played an active role in the formation of a friction layer, which was beneficial to the lower friction coefficient and wear rate. In light of this research, graphene plays an active role in reducing the friction coefficient and wear rate. Hence, graphene has great potential in applications as an effective solid lubricant to promote tribological behavior.     

多壁碳纳米管改性UHMWPE的热膨胀和摩擦学性能研究

为了降低摩擦副用聚合物的热膨胀系数,用多壁碳纳米管(MWCNTs)改性超高分子量聚乙烯(UHM-WPE),通过热压成型法制备MWCNTs/UHMWPE复合材料.通过测量电导率计算渗流阈值来表征分散性;用热膨胀仪(DIL)测试复合材料的热膨胀率,并在干摩擦环境下,测试不同MWCNTs含量复合材料的摩擦学性能.结果表明:通...     

Effect of humidity on the tribological behavior of carbon-carbon composites

The present work is a study of the effect of humidity on the tribological behavior of carbon-carbon composites, including two-dimensional PAN/pitch (designated TM), PAN/CVI (designated E), and pitch/resin/CVI (designated A) formulae. Results indicate that there exist close relationships among friction coefficient, wear rate, and worn surface morphology. Whenever a morphological transition has occurred, transitions in friction and wear also occur. Three different debris morphologies are identified. The smooth type I and type III debris films can lubricate, but not the powdery type II debris. The relative humidity level has a strong effect on the tribological behavior of all three composites. Low humidity and high sliding speed generally accelerate the occurrence of type I-to-type II transitions in friction, wear, and debris morphology, whereas high humidity and low speed enhance the formation of type III debris. At any humidity level, the type I morphology is always accompanied by low friction and wear. After the type I-to-type II transition, higher friction coefficient and wear rate are observed in the low humidity than in the high humidity. Under the present conditions, composite E appears to be the most sensitive to the humidity effect, while composite A appears the least sensitive.