不同填料填充的PTFE基粘结固体润滑涂层的摩擦磨损性能

金属粉体、陶瓷颗粒及玻璃微珠等可作为PTFE的改性填料提高其耐磨性,但过去少有上述填料用于PTFE基粘结固体润滑涂层耐磨改性的研究。制备了未添加填料的和分别填充Cu,SiC,c-BN,h-BN,玻璃微珠(T-60)的PTFE基粘结固体润滑涂层,评定了各涂层的附着力、耐冲击性;并考察了其在室温干摩擦条件下的滑动摩擦磨损性能,并分析了磨痕形貌。结果表明:各填充涂层附着力1～2级,抗冲击性良好;T-60和c-BN填充试样在试验条件下磨损量近乎为零,与未填充试样相比,SiC和h-BN填充试样磨损量分别下降82.9%,74.4%,Cu填充试样磨损量下降幅度最小;填充试样的磨痕均呈现出一定程度犁沟和切削,其中Cu填充试样磨痕深且宽,c-BN,SiC,T-60,h-BN填充试样磨痕浅且窄,c-BN和T-60填充试样磨损表面的转移膜最均匀;填料改变了粘结涂层的磨损机理,使其由单一的PTFE黏着磨损转变为以填料的磨粒磨损为主、PTFE的黏着磨损为辅的复合磨损,增强了涂层的抗极压承载能力和转移膜与基体间的结合力,提高了涂层的摩擦磨损性能。     

颗粒尺寸对反应烧结碳化硅摩擦磨损特性的影响

研究了碳化硅颗粒尺寸对反应烧结碳化硅材料摩擦磨损性能的影响.结果表明:随着碳化硅颗粒尺寸的增加,不论干摩擦还是水润滑条件下,反应烧结碳化硅的摩擦系数和磨损率均表现为先增加,后降低的趋势.粒度为42μm的反应烧结碳化硅的摩擦系数和磨损率最大,而粒度为14μm的最小.水润滑时的摩擦系数和磨损率比干摩擦时的成倍降低.     

稀土改性玻璃纤维对PTFE复合材料摩擦磨损性能的影响

分别用硅烷偶联剂SG-Si900(SGS)、含SG-Si900的稀土溶液(SGS/RES)和稀土溶液(RES)对玻璃纤维进行表面改性,考察了稀土改性玻璃纤维填充的PTFE复合材料在油润滑条件下的摩擦磨损性能,并用扫描电子显微镜(SEM)分析了磨损表面形貌.结果表明:与未经表面改性玻璃纤维填充的PTFE复合材料相比,经表面改性玻璃纤维填充的PTFE复合材料的减摩耐磨性能得到提高,以RES的作用最明显,SGS/RES次之,SGS第三;在油润滑条件下,稀土改性玻璃纤维填充的PTFE复合材料只出现了轻微磨损,这是由于玻璃纤维经稀土表面改性后极大地改善了玻璃纤维与PTFE基体之间的界面结合力,使稀土改性玻璃纤维填充的PTFE复合材料具有优异的摩擦磨损性能.     

纳米ZnO和SiO2共混填充UHMWPE复合材料的摩擦磨损行为

以纳米ZnO和纳米SiO2作为复合填料,通过热压成型工艺制备了纳米ZnO-SiO2复合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复合材料在干摩擦条件下与45#钢配副时的摩擦磨损行为;采用扫描电子显微镜观察了复合材料磨损表面形貌。结果表明,适量的纳米ZnO-SiO2作为复合填料可有效地改善UHMWPE的摩擦磨损性能,其中填充2%ZnO 2%SiO2的UHMWPE基复合材料改性效果最为明显。与纯UHMWPE材料相比,其磨损率下降了84.7%。纯UHMWPE的磨损机制主要表现为粘着磨损和疲劳磨损,而不同含量的无机纳米微粒共混填充UHMWPE基复合材料的磨损机制主要表现为不同程度的粘着磨损、犁沟效应和塑性变形特征。     

CHA/UHMWPE复合关节材料的生物摩擦学研究

采用热压成型工艺制备了超高分子量聚乙烯 (U HMWPE) /珊瑚羟基磷灰石 (CHA) 复合关节材料 , 利用人工髋关节模拟磨损试验系统 , 研究了该类复合材料与 CoCrMo 合金组合关节在小牛关节液润滑条件下的摩擦磨损性能。实验结果表明 , 添加 CHA 能有效提高 U HMWPE关节材料的表面硬度 , 降低其磨损率。当CHA添加量为 20 wt %时 , 可获得表面硬度与抗磨损性能的良好匹配。小牛关节液润滑条件下 , U HMWPE及其复合材料的磨损机理主要表现为研磨磨损和疲劳磨损 , 磨损颗粒尺寸随 CHA粉体添加量的增加而增大。      

SiCp/Al复合材料-半金属刹车材料干摩擦磨损性能研究

采用无压浸渗法制备15%(体积分数,下同),25%,35%,45%,55%的SiC颗粒(45,63μm)增强的铝基复合材料(SiCp/Al).在M-200型环块式磨损试验机上研究了SiCp/Al复合材料、灰铸铁(HT250)分别与半金属刹车材料配副的干摩擦磨损性能.结果表明,颗粒体积分数对复合材料摩擦系数的影响显著,而颗粒尺寸对复合材料摩擦系数影响不大.当颗粒体积分数从15%上升到55%时,SiCp(45μm)/Al复合材料的摩擦系数从0.319升高到0.385,提高20.7%,SiCp(63μm)/Al复合材料的摩擦系数从0.303升高到0.359,提高18.5%,且SiCp/Al复合材料摩擦系数的稳定性优于铸铁.HT250-刹车材料摩擦副的磨损率为7.09×10-6cm3m-1,是55%SiCp(45μm)/Al-刹车材料摩擦副的2.2倍,是55%SiCp(63μm)/Al-刹车材料摩擦副的2.7倍,SiCp/Al-刹车材料摩擦副的耐磨性明显优于铸铁-刹车材料摩擦副. SiCp/Al-刹车材料摩擦副的磨损率随着颗粒尺寸的增加而降低.     

玻璃纤维增强聚醚醚酮复合材料在水润滑下的摩擦学性能

利用球盘式摩擦磨损试验机考察了玻璃纤维(GF)增强聚醚醚酮(PEEK)复合材料在干摩擦和水润滑条件下的摩擦磨损性能,并探讨了其磨损机理。结果表明:在干摩擦和水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率均随载荷和对磨时间的增加逐渐增大并趋于稳定,GF的加入可以显著降低GF/PEEK复合材料的摩擦因数和磨损率;在水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率比干摩擦下显著降低。干摩擦下,PEEK以黏着磨损和磨粒磨损的混合磨损形式为主,水润滑条件下,磨损方式主要是以轻微的黏着磨损为主;干摩擦下,GF/PEEK磨损表面有大量的微观断裂裂纹和破碎,以磨粒磨损和疲劳磨损为主,水润滑条件下,磨损表面仅有微观切削的痕迹,磨损方式以轻微磨粒磨损为主。由于水的冷却和润滑作用,使得复合材料向对偶钢球的黏着转移明显减弱,同时阻止了对偶钢球上的Fe向复合材料磨损表面转移,从而减轻摩擦、降低摩擦表面温升,显著改善复合材料的摩擦磨损性能。     

CPR/NR和高性能填料对复合摩擦材料力学性能的影响

通过干法热压成型工艺制备性能优异的复合摩擦材料,研究了高性能填料以及改性酚醛树脂与丁腈橡胶质量比(CPR/NR)对复合摩擦材料性能的影响规律。对材料的摩擦磨损性能与力学性能进行了测试,借助热分析仪测试其耐热性能,并利用激光共聚焦显微镜、扫描电镜对表面形貌进行了观察和分析。结果表明,复合摩擦材料的密度、压缩强度、压缩模量、硬度随橡胶含量的减少而增加,冲击强度则呈相反的趋势。橡胶含量的减少,树脂比例的增加,使复合摩擦材料的耐热性得到提高,促进了第二接触面的形成,使摩擦系数与磨损率降低。高性能填料含量较低时,材料表面形成大且连续的第二接触面,第二接触面使摩擦系数、比磨损率降低,复合摩擦材料的主要磨损形式为粘着磨损与磨粒磨损;填料含量的增加会阻碍第二接触面的形成,使材料摩擦系数和比磨损率逐渐增大,材料的磨损形式由粘着磨损、磨粒磨损转变为磨粒磨损和疲劳磨损。     

不同纳米粒子填充PA6/GF复合材料摩擦磨损性能

利用MM-200型摩擦磨损试验机考察了载荷及不同纳米粒子与玻璃纤维混合填料对PA6复合材料摩擦磨损性能的影响。采用扫描电子显微镜观察分析磨损表面形貌及磨损机理。结果表明:纳米材料与玻璃纤维的协同作用显著改善了材料的摩擦磨损性能,其中纳米Si3N4与玻璃纤维混杂填充的PA6复合材料的耐磨性最佳;纳米SiO2与玻璃纤维混杂填充的PA6复合材料的摩擦性能最佳。     

空心玻璃微珠/超高分子量聚乙烯复合材料低速重载工况下的摩擦磨损性能

为提升超高分子量聚乙烯(UHMWPE)材料在低速、重载工况下的摩擦磨损性能,使用经偶联剂表面处理的空心玻璃微珠(HGM)对UHMWPE进行填充改性,通过热压成型工艺制备HGM/UHMWPE复合材料。对HGM/UHMWPE复合材料的硬度、结晶度等进行表征,并对该材料进行干摩擦环境下的重载球盘往复摩擦试验以测定其摩擦磨损性能。结果表明,添加少量HGM可以提高UHMWPE的硬度与结晶度。当摩擦时间较短时,加入HGM会在一定程度上增大UHMWPE的摩擦系数,同时磨损率随复合材料中HGM含量的增加而先降低后升高,当HGM含量为1wt%时,复合材料磨损率最低,在50 N与100 N两种法向载荷的摩擦试验中相比于纯UHMWPE磨损率分别降低44.7%与48.4%。随着摩擦时间的增长,复合材料摩擦系数与磨损率均有不同程度的升高。当摩擦时间达到120 min时,HGM含量为2wt%的复合材料平均摩擦系数最低。此时添加少量HGM的HGM/UHMWPE复合材料在磨损率上与纯UHMWPE磨损率接近。     

Synthesis and characterization of polyurethane – Treated waste milled light bulbs composites

In this study, polyurethane (PU)-milled light bulbs glass composites were synthesized and characterized. The main interest in this study that the polyurethane derived from renewable resources and waste glass are used to form the composite constituents as an attempt towards environmental preservation. Castor oil and polymeric diphenyl methane di-isocyanates (PMDI) were used in NCO/OH ratio = 2 for polyurethane synthesis. Milled glass with average particles size less than 300 μm were prepared based on waste light bulbs. Silane A1100 (as a compatibilizer) was used in order to improve the value of recycled milled glass beads. The adhesion force between polyurethane matrix and milled glass beads was evaluated using mechanical and physical tests. Scanning electron microscopy (SEM) was used to investigate dispersion and fracture surfaces of the composites. Infrared spectrum (IR), Differential scanning calorimetry (DSC) behavior, and Thermogravimetric analysis (TGA), were employed to characterize the developed composite materials in details. Chemical resistance (weight change, thickness swelling) was measured in oil, water and dilute acetic acid media. Furthermore, tensile strength and hardness were investigated using universal materials testing machines. A slight increase in the hardness values was reported along with the increasing in particulate fillers loading up to 10% as a considerable improvement has been detected when milled glass reached 20%. The DSC analysis showed the presence of treated milled glass beads influences the thermal behavior of pure PU and composites. This can be attributed to enhancing the physical bonding between PU and silica group. Waste milled glass showed a significant effect on the thermal degradation of the composites in the presence of coupling agent. Further analysis on the tensile strength of the composites indicated that such improved mechanical properties may be attributed to the presence of coupling agent.     

石墨/聚四氟乙烯/玻璃纤维改性PA6的力学和摩擦磨损性能

采用石墨(Gr)、聚四氟乙烯(PTFE)和玻璃纤维(GF)改性聚酰胺6(PA6),以提高PA6的摩擦磨损性能和力学性能。重点研究了填料组合、配比、载荷和转速对复合材料摩擦磨损性能的影响,通过磨损表面形貌分析探讨了摩擦磨损机理。结果表明:Gr/PTFE/GF混杂改性PA6能明显降低摩擦系数并提高耐磨性,PA6/Gr/PTFE/GF质量比为70/5/10/15时摩擦系数和磨损率最低,且在高转速(40N,1500r/min)下摩擦磨损性能更好,摩擦系数为0.08,比PA6降低了27%,磨损率为5.5×10~(-6) mm~3/(N·m),比PA6降低了1个数量级,且该复合材料的拉伸强度、冲击强度、储能模量和损耗模量都高于PA6。     

Study of Abrasive Wear Volume Map for PTFE and PTFE Composites

The potential of this work is based on consideration of wear volume map for the evaluation of abrasive wear performance of polytetrafluoroethylene (PTFE) and PTFE composites. The fillers used in the composite are 25% bronze, 35% graphite and 17% glass fibre glass (GFR). The influence of filler materials, abrasion surface roughness and applied load values on abrasive wear performance of PTFE and PTFE composites were studied and evaluated. Experimental abrasive wear tests were carried out at atmospheric condition on pin-on-disc wear tribometer. Tests were performed under 4, 6, 8 and 10 N load values, travelling speed of 1 m/sec and abrasion surface roughness values of 5, 20 and 45 μm. Wear volume maps were obtained and the results showed that the lowest wear volume rate for PTFE is reached using GFR filler. Furthermore, the results also showed that the higher is the applied load and the roughness of the abrasion surface, the higher is the wear rate. Finally it is also concluded that abrasive wear process mechanism include ploughing and cutting mechanisms.     

Abrasive Wear Volume Maps for PA6 and PA6 Composites Under Dry Working Condition

In this study the wear volume map is obtained and considered for evaluation of the abrasive wear performance for polyamide (PA6) and PA6 composites. Polyamide composites were tailored using 25 wt.% glass bead, 20 wt.% talc and 30 wt.% wollastonite fillers. In this work, the influence of filler materials, abrasion surface roughness and applied loading values on abrasive wear performance of PA6 and PA6 composites were evaluated. Experimental abrasive wear tests were carried out at atmospheric condition using pin-on-disc rig arrangement. Tests were performed under 4, 6, 8 and 10 N load values, traveling speed of 1 m/s and abrasion surface roughness values of 5, 20 and 45 μm. Wear volume maps were obtained and the results showed that the lowest wear volume rate for PA is reached using glass bead filler. Furthermore, the results also showed that the higher is the applied load and the roughness of the abrasion surface, the higher is the wear rate. Finally it is also concluded that abrasive wear process mechanism include ploughing mechanism and delimitation of filler tips.     

Wear behavior of aluminum-coated glass compared to uncoated glass investigated by cyclic wear tests in the micrometer scale

Micro wear tests have been conducted on soda lime glass covered with a 4.5 μm aluminum film and on an uncoated glass substrate. High resolution lateral force-displacement measurements were carried out with a spherical diamond indenter of 6 μm radius while the normal force was kept constant. The wear behavior was investigated for different normal loads (100 mN, 200 mN), different scratch lengths (10 μm, 40 μm) and different lateral sliding speed (5 μm/s, 10 μm/s, 20 μm/s). These conditions were used as a model for the characterization of surface damage by hard wear particles. The average friction coefficient and the average normal displacement per cycle were calculated and their change was used for the characterization of the wear behavior. Significant changes could be observed in the dependence on the wear parameters and the cycle number. Thus, wear dominated by plastic deformation and fracture-dominated wear could be distinguished. The soft aluminum coating on the brittle glass prevents fracture-dominated wear of the glass even after the failure of the coating. The wear rate of the glass is considerably decreased if only wear by plastic deformation occurs.     

填料对阻尼隔声材料的水中插入损失的影响

本文研究了空心玻璃微珠、粉煤灰 (煤胞 )、发泡聚合物等填料对阻尼隔声橡胶材料水中插入损失的影响 ,发现橡胶中加入隔声填料可以明显提高水中插入损失。其中玻璃微珠插入损失最大 ,其次是粉煤灰 ,再次为发泡聚合物 ,而前三者等量混合物略差。玻璃微珠用量以 3 0份为宜 ,水中插入损失随用量增加而降低 ,在3kHz、1 0kHz、2 0kHz三个频段 ,用量 3 0份至 5 0份时 ,插入损失降低幅度较大 ,5 0份以后降低幅度变缓 ,其他频率也有类似情况     

Elastic properties measurement of glass layers fabricated onsilicon wafers for microelectronics and micromachines

Elastic properties such as the Young's modulus, the Poisson's ratio and the density of Si-B-O glass layers fabricated on (100) silicon substrates by the flame hydrolysis deposition method were measured. Thicknesses of the layers were about 20 μm. It was found that the Young's modulus decreased with the boron dopant concentration. The Poisson's ratio was about 0.26 regardless of the boron dopant concentration. The measured elastic properties will be used in the design of micromachines fabricated with silicon substrates and glass layers     

碳纤维和二硫化钼混杂增强尼龙复合材料的摩擦学性能研究

以注塑成型法制备MoS₂和碳纤维混杂增强尼龙1010复合材料,采用MM-200型磨损试验机考察复合材料摩擦磨损性能。研究结果表明:在干摩擦条件下,MoS₂和碳纤维混杂可显著改善尼龙复合材料摩擦学性能,较小载荷下复合材料磨损以轻微磨粒磨损和疲劳磨损为主,较高载荷下复合材料则以热疲劳断裂剥落磨损为主。摩擦过程中MoS₂和对偶铁发生摩擦化学反应,生成和对偶底材具有较强结合能力的硫化亚铁和硫酸铁等,同时部分被氧化生成MoO₃。     

Effect of oil and oil with graphite on tribological properties of glass filled PTFE polymer composites

Present work deals with the experimental investigation of tribological properties of GF-filled polymer composites considering three velocities, i.e. 0.5, 1 and 2.0 m/s and loads ranging from 15.7 N to 45.13 N keeping rest of the parameters constant. The test has been carried out for three materials, PTFE + 15% GF, PTFE + 25% GF and PTFE + 35% GF in wet (oil) and adding additive as graphite (5% wt) in oil. SAE 20W40 oil is used for the test. Friction and wear tests of PTFE composite against a counter surface of EN8 with surface finish of 0.56 μm are carried out at ambient conditions using pin-on-disc tribometre (TR-20), Ducom make, Bangalore. The results are tabulated and graphs are plotted. It has been found that load and wet conditions have significant effect on coefficient of friction and specific wear rate of the materials. Where as sliding velocity also plays little role in wear mechanism of the material. It is concluded from the experimental study that the specific wear rate in wet condition as well as by adding additives in lubricating oil with 5% (by wt.) has been declined. Also the specific wear rate decreases with normal load and sliding velocity. Wear of PTFE + GF composite decreases with increase in glass percentage. Microscopic analysis of pin and disc surface is made with optical microscope. The mathematical models has been developed by using regression analysis and found to be valid for the above tested parameters.     

应用宽频介电谱研究氢氧化铝/环氧树脂复合材料的α和β松弛行为

聚合物的松弛行为直接影响其使用范围。本文应用宽频介电谱技术研究了中心粒径为2 μm的氢氧化铝（ATH）填料对环氧树脂复合材料α和β松弛过程的影响。宽频介电谱的测试频率范围为0.1 Hz~2 MHz,温度范围为-100~100℃。ATH填料与环氧树脂的质量比为0%、20%、40%、60%、80%和100%。结果表明：填料对复合材料的α松弛过程影响较小,Vogel温度随填料的增加先减小后增大;β松弛的表观活化能随填料的增加先增大后减小,当ATH填料质量比为40%时,β松弛的表观活化能达到最大值。