聚四氟乙烯、聚醚醚酮和热固性树脂材料的摩擦磨损性能及差异性研究

选取了聚四氟乙烯(PTFE)、聚醚醚酮(PEEK)和热固性树脂3种常用于制备水润滑轴承的材料,测试了它们在不同载荷、不同转速和不同润滑状况下的摩擦磨损性能.研究结果表明,同种材料在不同润滑状况下的摩擦系数波动幅度有明显差别.在转速逐渐升高的条件下,热固性树脂材料和聚四氟乙烯材料的摩擦性能有一定提高,而聚醚醚酮材料的摩擦性能变化不大.PTFE材料在干摩擦状态下的磨损方式主要为粘着磨损和疲劳磨损,而在水润滑状态下的疲劳磨损程度加剧.     

指尖密封用炭-炭复合材料摩擦磨损性能

为确定指尖密封用炭-炭(炭纤维增强炭基体)复合材料的摩擦学性能,针对指尖密封的轻载使用条件,应用UMT-2摩擦磨损测试仪进行炭-炭复合材料摩擦磨损性能试验,测量摩擦系数与磨损率,并采用扫描电子显微镜(SEM)分析材料的摩擦磨损机理.结果表明,无纬布层垂直于摩擦平面时,材料的摩擦系数和磨损率较低.载荷增加,较高密度材料的磨损率增加缓慢,摩擦系数减小.与载荷相比,材料磨损率受频率的影响较小,且随频率升高摩擦磨损性能越好.磨损表面的SEM分析表明:低频、低载条件下材料发生磨粒磨损;频率的提高加快磨屑膜的成形,自润滑能力增强;载荷的增加虽使磨屑快速被挤压形成磨屑膜,但磨屑膜被不断挤出剥落,纤维裸露断裂产生严重磨损,这一点在材料密度较低时表现更为显著.选用较高密度的材料以及布置无纬布层垂直于摩擦平面可以有效缓解密封材料的磨损.     

40Cr/石墨关节轴承摩擦学性能及磨损机理研究

针对某核电阻尼器用自润滑关节轴承不允许使用聚四氟乙烯(PTFE)和铜材质零件的需求,研制了一种40Cr/石墨关节轴承。为了研究该液压阻尼器摆动工况对关节轴承的影响,首先通过自研的关节轴承负载模拟台对该关节轴承在10 kN的径向载荷、1 Hz的摆动频率和±5°的摆幅下进行了50 000次摆动摩擦实验;然后利用实验过程中记录的摩擦力矩、径向磨损量和摩擦温度分析了石墨与40Cr长时间对摩的摩擦学性能变化;最后借助双束扫描电子显微镜所获取的石墨内圈微观形貌探讨了实验工况下该关节轴承的磨损机理。实验结果表明：在磨合阶段,磨损量、摩擦系数和温度呈现大幅提高,然后过渡到稳定磨损阶段,在稳定磨损阶段的后期,均呈现小幅上升趋势;轴承在整个摆动磨损过程中运动状态良好,无卡死现象,实验结束后轴承径向磨损量为112μm、内圈质量减少0.02 g;石墨内圈在不同接触位置上呈现不同的磨损机理,核心承压区主要为磨粒磨损、疲劳磨损和黏着磨损,非核心承压区主要为磨粒磨损。     

边界润滑条件下钢/钢滑动磨损P—V磨损机制图研究

本文在销环式磨损试验机上采用阶梯加载方式,将润滑状态、摩擦系数、磨损表面形貌、表面膜等综合起来,研究了边界润滑钢/钢滑动磨损P—V磨损机制图,并论证了机制转化的原因。研究表明:新的P—V图中磨损机制由边界润滑轻微磨损转化为于摩擦严重磨损,经过渡区进入边界润滑轻微磨损而不是熔化磨损。氧化膜的形成是严重磨损向轻微磨损转化的主要原因;高速高载下保持轻微磨损是白层组织硬化的结果。     

石墨含量对风电机组用铜基摩擦材料摩擦磨损性能的影响

采用粉末冶金技术制备风电机组用的铜基摩擦材料。研究在不同的摩擦速度下,石墨的含量对材料的摩擦磨损性能的影响。结果表明:材料的磨损率随着摩擦速度的增加而增加。随着石墨含量的增加,材料的磨损率增加,由于石墨破坏基体的连续性使得材料的强度降低,从而使材料的磨损率增加。材料的摩擦系数随着石墨含量的增加而降低,这是因为材料摩擦过程中摩擦表面形成具有润滑作用的摩擦膜。石墨含量为10%的材料具有较好的摩擦磨损性能。     

WC—NiP合金密封材料与不同软材料组对时的摩擦性能

对研究开发的一种机械密封新型摩擦副材料ＷＣ－ＮｉＰ合金与不同软材料组对时的摩擦特性进行了研究,考察了在水润滑条件下ＷＣ－ＮｉＰ／浸呋喃树脂石墨配对的摩擦性能,并分别与浸润石墨,浸玻璃石墨和填充聚四氟乙烯配对作了对比,结果表明,ＷＣ－ＮｉＰ合金作为硬环材料时,与之组对软环材料为浸呋喃权脂石墨时其摩擦性能最优,并得出摩擦系数的并联式。     

粘结石墨基固体润滑涂层的微动摩擦磨损性能

为了探讨粘结石墨基固体润滑涂层的微动摩擦磨损性能的作用机理,使用SRV微动摩擦磨损试验机对粘结石墨基固体润滑涂层在微动试验条件下的摩擦学性能以及抗承载能力进行研究,对其磨痕形貌和对偶转移膜进行分析。研究结果表明：粘结石墨基固体润滑涂层的磨损率随着试验载荷和摩擦速度的增大而减小;而摩擦因数随着试验载荷增大而减小,随摩擦速度增大而缓慢增大;在微动摩擦过程中,高载高速可以促进高质量转移膜在对偶表面形成,从而使得粘结石墨基固体润滑涂层具有良好的抗承载能力和优异的抗磨减摩性能。     

QPQ表面疏松层纯磨损试验研究

在M-2000型磨损试验机上进行纯磨损试验,研究了QPQ表面改性层在浸油擦干后的滑动干摩擦磨损过程。根据磨损曲线和摩擦系数的变化,发现其摩擦磨损过程存在一个干摩擦向边界摩擦过渡的亚稳定阶段,稳定阶段的磨损率和摩擦系数仅为未浸油干摩擦磨损试验时的三分之一。利用SEM分析各阶段磨损表面形貌,QPQ表面改性层磨合阶段的主要磨损机理为黏着磨损,亚稳定和稳定阶段对应的磨损机理为显微切削和划伤。试验结果表明,QPQ表面改性层外表面存在一定程度的疏松层可以储存润滑油,降低摩擦因数,避免或减轻了黏着磨损及磨粒磨损。     

Al2O3陶瓷与铸铁副在空气和蒸馏水润滑下的滑动磨损

在室温、干摩擦(空气)及蒸馏水润滑条件下使用环块磨损试验机进行Al2O3陶瓷和球墨铸铁、灰铸铁及钢配副时的滑动磨损试验.结果表明:蒸馏水润滑下Al2O3及铸铁的磨损体积均小于在干磨擦条件下;在同一润滑条件下,钢的磨损体积大于铸铁磨损体积,球墨铸铁磨损体积最小;陶瓷Al2O3磨损体积在干摩擦时与铸铁配副时比与钢配副时要小得多.对Al2O3磨面进行形貌及能谱分析,发现在干摩擦条件下,Al2O3磨面有大量铸铁或钢的转移物组成的迁移膜,在蒸馏水润滑条件下则没有.分析认为,铸铁中石墨在于摩擦时能起到较明显的固体润滑剂作用,相对地减小了磨损,而在蒸馏水润滑下石墨的润滑作用己大大减弱.     

多孔阵列阳极氧化铝膜润滑性能的Stribeck研究

为了研究阳极氧化铝膜的多孔结构对其润滑性能的影响,分别制备了光滑表面氧化铝膜,40 nm孔径、90 nm孔径多孔表面氧化铝膜.用接触角测试仪测试了水、机油与3种表面的接触角;在不同润滑条件下,用摩擦磨损试验机UMT-2测试了3种氧化铝膜与GCrl5钢面接触的润滑性能.结果表明:多孔结构氧化铝膜增强了材料的亲水性能和亲油性能,90 nm孔径氧化铝膜表现出超亲油特征;水润滑和机油润滑条件下,速度从0.016 m/s增至0.32 m/s过程中,光滑氧化铝表面只能形成边界润滑区域,多孔表面得到了包含边界润滑、混合润滑和流体润滑的完整的Stibeck曲线.机油润滑条件下,40 nm孔径的膜达到最小摩擦系数的临界速度为0.28 m/s,最小摩擦系数为0.083,90 nm孔径的膜达到最小摩擦系数的临界速度仅为0.2 m/s,最小摩擦系数减小为0.023;机油润滑条件下,90 nm孔径的氧化铝膜板的Stribeck曲线,谷底区域更宽.     

Research on Percolation Network and Physical Properties of Graphite/Antimony Composites

The microstructure, friction and wear behaviour of graphite preform and graphite/antimony composites are analysed based on the percolation theory of hydrodynamics to investigate the relationship between the percolation network and physical properties of graphite/antimony composites. The result shows that there are two important factors to enhance friction and wear behaviour of graphite/antimony composites at high temperature： 1） the formation of the pore network in the preform, which is called the first percolation and 2） the optimization of infiltration method in the process of infiltrating antimony, which is called the second percolation. By adding some pyrolysate and controlling the roasting process, perfect net pores and sub-micron percolation microstructure may be formed in the graphite preform. By con- trolling the infiltration process, the saturation of molten antimony infiltrating into perfect pores can be optimized.     

Effect of filler on the self-lubrication performance of graphite antimony composites

Graphite antimony composites were prepared using a mechanical pressure infiltration method to force molten antimony into graphite preforms having a percolation micro-structure and a hop-pocket power filler. The micro-structural and macroscopic properties of the graphite antimony composites were analysed. Observations included metallographic analysis, physical properties and friction and wear behaviour. The results show that the wear loss is decreased by 12.24% and that the friction coefficient is re-duced by 32.61% after hop-pocket power was used. The research indicates that the hop-pocket power method gives a useful way to reduce friction coefficients and wear loss, and to increase service life and self-lubrication properties, of the graphite antimony seal-ing material as compared to carbon black.     

基于Matlab的浸锑石墨密封材料的分形特征研究

针对电厂用的2种浸锑和1种不浸锑的磨煤机用石墨密环材料,利用Matlab编写的分形维数计算程序计算其分形维数,并进行摩擦磨损实验.结果表明:未浸锑材料的相对磨损率约为浸锑的10～30倍,摩擦因素约为2倍;浸锑石墨材料的分形维数(约1.5～1.7)小于不浸锑的(约1.8);摩擦因数随着分形维的增加而增大,磨损量亦随着分形维数的增加而增大.     

Lubricating properties of polyalkylene glycol and organic phosphate ester mixed aqueous solutions

Till now,water based lubricants,especially aqueous solutions,have not been employed in the elastohydrodynamic lubrication(EHL)due to their poor film forming capability or low wear resistance.In this paper,we proposed a method to develop water based lubricant:employing polyalkylene glycol solution as base stock to improve EHL film forming capability and using organic phosphate ester(DPZ)as anti-wear additive to improve wear resistance property.The lubricating properties of the mixed solutions,including load carrying capability,wear resistance property,friction reduction property,EHL film forming behavior,were investigated.The experimental results indicate that the mixed solution presents excellent lubricating properties,which make it a promising candidate in developing water based lubricants.     

混杂增强AZ91复合材料的制备及其显微组织和性能

采用挤压铸造方法制备了以AZ91镁合金为基体、Al2O3短纤维(Al2O3f)和石墨颗粒(Grp)混杂为增强体的复合材料。观察了不同复合材料的显微组织,测试了其力学性能,并对其摩擦磨损性能进行了研究。结果表明:用此法制备的镁基复合材料增强相分布均匀,与基体结合紧密。硬度随Grp体积分数的增加而降低,Al2O3f的加入能提高复合材料的硬度。抗拉强度和伸长率都随Grp体积分数的增加而减小。Grp体积分数增加,磨损质量损失和摩擦系数都降低。随着摩擦过程的进行,在试样表面逐渐形成一层黑色连续的润滑膜。     

Effect of Friction Coefficient on Deep Drawing of 6A16 Aluminum Alloy for Automobile Body

Based on the ABAQUS/Explicit finite element method, the forming force changing trend of deep drawing test for 6 A16 aluminum alloy plate after pre-aging and storage at room temperature for one month was simulated under friction coefficient ranging from 0 to 0.22. The lubricants selected for the tests were mechanical oil, butter and dry film lubricant, and the friction coefficient of these lubricants were 0.05, 0.10 and 0.15, respectively. Microstructural evolution of 6 A16 aluminum alloy plate during drawing forming was investigated by OM, SEM and EBSD. The results showed that, with the increase of friction coefficient, the stress, strain and deformation degree in deformation zone increased, while the grain size in deformation zone decreased. Thus, the hardness of the cup-typed component increased with the increase of friction coefficient. Butter-lubricated cups had the highest tensile strength and yield strength after paint-bake cycle. The combination of simulation results and microstructure analysis of 6 A16 aluminum alloy plate after drawing forming indicates that the appropriate lubricant is butter.     

改性UHMWPE塑料的摩擦磨损性能研究

分别研究MoS2、PTFE和石墨对UHMWPE耐摩擦性能的影响。结果表明:在载荷200 N,转速400 r/min的试验条件下,UHMWPE/石墨、UHMWPE、UHMWPE/MoS2和UHMWPE/PTFE的平均摩擦系数分别为0.27,0.30,0.35和0.39。掺杂石墨(质量分数9%)降低了UHMWPE的摩擦系数,在试验过程中减少了由于摩擦而产生的热量,从而提高了UHMWPE/石墨复合材料的耐磨性能。     

对偶表面粗糙度对Nano-SiO2改性PTFE复合材料摩擦学性能的影响

为了研究干摩擦条件下对偶表面粗糙度对纳米粒子填充改性聚四氟乙烯（PTFE）复合材料摩擦磨损及转移膜特性的影响规律,本文采用冷压成型、热烧结的工艺方法制备nano-SiO2填充改性PTFE复合材料;采用LSR-2M型往复摩擦磨损试验机评价了nano-SiO2改性PTFE复合材料与具有三种不同表面粗糙度的对偶钢块（GCr15）之间的摩擦磨损性能;利用光学显微镜（OM）、扫描电子显微镜（SEM）和能谱仪（EDS）分别表征了转移膜及磨屑的形貌、微观结构以及化学成分,从微观角度揭示nano-SiO2改性PTFE复合材料的摩擦转移机理。试验结果表明,纯PTFE及不同含量nano-SiO2填充改性PTFE复合材料的摩擦系数均随对偶钢块表面粗糙度的增大整体呈增大趋势,在粗糙度为Ra0.1的对偶表面上复合材料的摩擦系数随着nano-SiO2含量的增加变化相对较小;在三种不同粗糙度对偶表面上,nano-SiO2的加入均有效降低了PTFE的磨损体积,当填充比例为0.5wt%时复合材料在粗糙度为Ra1.2的对偶面上摩擦学性能最佳,磨合时间约为纯PTFE的1/3（缩短了近10min）,耐磨性较纯PTFE提高了34.1%。由此可见,复合材料中nano-SiO2的含量与对偶表面粗糙度存在一定的协同效应,即nano-SiO2的含量与对偶表面粗糙度具有匹配性,合理的摩擦配副能有效促进复合材料的摩擦转移,并能在对偶表面形成覆盖率高、均匀、连续、表面较粗糙且与摩擦方向趋向一致的转移膜,有利于降低材料的磨损。     

Tribological behavior of hot-pressed boron carbide with oxidation

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Tribological Behaviours of PTFE Composites Filled with PEEK and Nano-ZrO_2 Based on Pin-on-Flat Reciprocating Friction Model

Nano-Zr O_2 and PEEK particles were synergistically filled in unfilled PTFE to improve the wear resistance and maintain a relatively low friction coefficient, and the materials were studied using a reciprocating sliding friction and wear tester. In the friction tests, the evolution of various tribological characteristics in both the contact interfaces and debris was observed, and the wear mechanism of the PTFE composites was investigated. The results showed that the wear rate of the PTFE composites synergistically filled with nano-Zr O_2 and PEEK was lower and its friction coefficient was slightly higher than that of the unfilled PTFE; the uniformity and continuity of the transfer film generated by the composite with nano-Zr O_2 and PEEK were the best, and the particle size of the debris was minimal in comparison to that in other sample systems.