润滑油添加剂对聚合物及其复合材料摩擦磨损性能的影响

利用MHK-500型环-块磨损试验机研究了二烷基二硫代磷酸锌(ZDDP)对几种聚合物及其复合材料-金属摩擦副油润滑摩擦磨损性能的影响。结果表明,液体石蜡中的ZDDP对尼龙66(PA66)及聚酰亚胺(PI)-GCr15轴承钢摩擦副的摩擦系数影响不大,但却使聚四氟乙烯(PTEE)及其复合材料-GCr15轴承钢摩擦副的摩擦系数略有降低。PTEE及其复合材料-GCr15轴承钢摩擦副表面的ZDDP吸附膜具有一定的抗磨作用,它大幅度降低了Pb、PbO及MoS     

润滑油添加剂对聚合物及其复事材料磨擦磨损性能的影响

利用ＭＨＫ－５００型环－块磨损试验机研究了二烷基二硫代磷酸锌（ＺＤＤＰ）对几种聚合物及其复材料－金属摩擦副油润滑摩擦磨损性能的影响。结果表明，液体石蜡中的ＺＤＤＰ对尼龙６６（ＰＡ６６）及聚酰亚胺（ＰＩ）－ＧＣｒ１５轴承钢摩擦副的摩擦系数影响不大，但却使聚四氟乙烯（ＰＴＦＥ）及其复合材料－ＧＣｒ１５轴承钢摩擦副的摩擦系数略有限低。ＰＴＦＥ及其复合材料－ＧＣｒ１５轴承钢摩擦副表面的ＺＤＤＰ吸附膜具有一     

PTFE基三层滑动轴承材料与不同材料配副时的摩擦学特性

PTFE基三层滑动轴承复合材料与不同材料组成的摩擦副有着不同的摩擦学特性,研究这些摩擦副的摩擦学特性,对于优化摩擦副配副材料具有重要的实用价值。研究PTFE基三层复合材料与钢铁材料、有色金属以及聚合物材料进行配副时的摩擦磨损性能,通过扫描电镜观察磨损表面的微观形貌,分析不同摩擦副的摩擦磨损机制,并给出摩擦副配副的优选结果。结果表明:PTFE基三层滑动轴承材料与钢铁材料以及聚合物材料配副时,其磨损机制为剥层磨损,摩擦学性能较好;而与有色金属配副时,其磨损机制为黏着磨损,摩擦学性能较差。     

超音速微粒轰击40Cr钢的摩擦学性能

利用超音速微粒轰击技术(SSPB)对退火态40Cr钢进行表面处理。研究SSPB处理后材料在液体石蜡和含0.30%的二烷基二硫代磷酸锌(ZDDP)的液体石蜡润滑下的摩擦性能,并与未轰击处理样品和轰击后抛光样品在相同润滑条件下的摩擦性能进行比较;利用扫描电子显微镜观察了摩擦实验后的表面形貌。结果表明,在2种润滑条件下的3种样品中,轰击后抛光样品的摩擦性能最好,未轰击样品次之,轰击处理样品的摩擦性能最差;在相同载荷下,LP润滑时试样的磨损量大于含ZDDP的LP润滑时的磨损量;扫描电子显微镜的磨损形貌分析与磨损实验结果相吻合。     

海水环境下陶瓷材料的摩擦学行为研究现状

综述海水环境下陶瓷材料与陶瓷、金属、聚合物等材料配副在海水环境下的摩擦学行为的研究现状,以及海水环境下陶瓷配副材料的发展趋势和应用前景。指出在海水环境下陶瓷与陶瓷配副材料的研究需综合考虑水分子对摩擦副摩擦磨损的抑制和促进作用,陶瓷与聚合物配副材料的研究需考虑对偶件腐蚀和吸水塑化等现象的影响,陶瓷与金属配副材料的研究应完善化学腐蚀和机械磨损交互作用的定量分析。建议应建立陶瓷摩擦副材料试验技术数据库并开发其评价体系,使得陶瓷摩擦副材料性能评价指标化、定量化。     

直链脂肪酸与直链脂肪醇混合对钢—钢和钢—铝摩擦副摩擦磨损性能的影响研究

本文利用四球摩擦磨损试验机和SRV摩擦磨损试验机研究了直链脂肪酸和直链脂肪醇以及其混合物对钢－钢、钢－铝摩擦副的摩擦磨损性能的影响。结果表明，对钢－钢和钢－铝摩擦副的润滑，直链脂肪酸和直链脂肪醇混合物的抗磨性能要优于单独的直链脂肪酸和直链脂肪醇的抗磨性能。     

干滑动条件下45CrNi材料摩擦磨损规律研究

以某自行火炮底座传动箱摩擦副所用材料45CrNi为研究对象，考察了该材料在不同热处理状态下（530℃回火、380℃回火、830℃淬火及原始状态）组成摩擦副时的干滑动摩擦磨损特性。试验结果表明：530℃回火盘和摩始销组成摩擦配副时结合最好，具有较好的摩擦磨损性能，销试样磨损率最小；在较低速度下载荷是影响材料摩擦因数的主要因素，而速度对摩擦因数的影响较小；粘着磨损是材料配副磨损的主要形式。     

聚合物运动摩擦件二维温度场的有限元分析

作为零部件材料，聚合物及聚合物基复合材料在石油化工机械和石油机械中得到越来越广泛的应用，摩擦温升是影响其成品件磨损特性的重要因素。本文以销—盘基本摩擦副为研究对象，应用有限元法分析研究了聚合物和聚合物基复合材料销的端面摩擦生热问题，给出了销的二维温度场，其结果与有关文献给出的实验结果吻合较好。     

脂肪醇对Ti6Al4V/钢摩擦副摩擦磨损性能的影响

采用SRV型摩擦磨损试验机分别考察了Ti6Al4V/钢摩擦副在多种脂肪醇润滑下的摩擦磨损性能。结果表明,与液体石蜡相比,碳链长度小于碳8的脂肪醇作为Ti6Al4V/钢摩擦副的润滑剂表现出良好的润滑性能,其润滑机制是在Ti6Al4V磨损表面形成吸附膜。载荷和频率明显影响Ti6Al4V/钢摩擦副在脂肪醇润滑下的摩擦磨损行为和摩擦磨损机制:当载荷较小时,Ti6Al4V磨损表面主要发生轻微的擦伤;随着载荷增加,Ti6Al4V磨损表面擦伤严重并在更高载荷下发生较为严重犁沟和塑性变形。     

不同摩擦状态下ZA81M镁合金磨损行为研究

采用往复式摩擦磨损试验机测试ZA81M镁合金在干摩擦及油润滑下的磨损行为，研究二辛基二硫代磷酸锌(ZDDP)和砂粒的含量对ZA81M镁合金在油润滑下摩擦学性能的影响，探讨ZA81M镁合金在不同摩擦状态下的摩擦学作用机理。结果表明：干摩擦下，ZA81M镁合金磨损量和摩擦系数随着载荷的增加而增加，随着往复频率的增加而减小。与干摩擦相比，68#机械油润滑下的ZA81M镁合金磨损量和摩擦系数降低。在68#机械油中添加ZDDP后，ZA81M镁合金磨损量和摩擦系数进一步降低，ZDDP中的化学元素与镁合金表面生成了易剪切的摩擦反应膜。在含ZDDP的68#机械油中添加砂粒后，摩擦反应膜被破坏，磨损量和摩擦系数增加。     

Friction and wear characteristics of lead and its compounds filled polytetrafluoroethylene composites under oil lubricated conditions

The friction and wear properties of Pb, PbO, Pb₃O₄, or PbS filled polytetrafluoroethylene (PTFE) composites sliding against GCr15 bearing steel under both dry and liquid paraffin lubricated conditions were studied by using an MHK-500 ring-block wear tester. The worn surfaces and the transfer films of these PTFE composites formed on the surface of GCr15 bearing steel were then investigated by using a scanning electron microscope (SEM) and an optical microscope, respectively. Experimental results show that filling Pb, PbO, Pb₃O₄ or PbS to PTFE can greatly reduce the wear of the PTFE composites, but the wear reducing action of Pb₃O₄ is the most effective. Meanwhile, PbS increases the friction coefficient of the PTFE composite, but Pb and Pb₃O₄ reduce the friction coefficients of the PTFE composites. However, the friction and wear properties of lead or its compounds filled PTFE composites can be greatly improved by lubrication with liquid paraffin, and the friction coefficients of the PTFE composites can be decreased by one order of magnitude. Optical microscope investigation of transfer films shows that Pb, PbO, Pb₃O₄ and PbS enhance the adhesion of the transfer films to the surface of GCr15 bearing steel, so they greatly reduce the wear of the PTFE composites. However, the transfer of the PTFE composites onto the surface of GCr15 bearing steel can be greatly reduced by lubrication with liquid paraffin, but the transfer still takes place. SEM examination of worn surfaces shows that the interaction between liquid paraffin and the PTFE composites creates some cracks on the worn surfaces of the PTFE composites; the creation and development of the cracks reduces the load-carrying capacity of the PTFE composites, and this leads to deterioration of the friction and wear properties of the PTFE composites filled with lead or its compounds under higher loads in liquid paraffin lubrication.     

Friction and wear properties of metal powder filled PTFE composites under oil lubricated conditions

Four kinds of polytetrafluoroethylene (PTFE)-based composite, pure PTFE, PTFE+30vol.%Cu, PTFE+30vol.%Pb and PTFE+30vol.%Ni composite, were prepared. The friction and wear properties of these metal powder filled PTFE composites sliding against GCr15 bearing steel under both dry and lubricated conditions were studied using an MHK-500 ring-block wear tester. The worn surfaces of the PTFE composites and the transfer films formed on the surface of GCr15 bearing steel were examined using scanning electron microscopy (SEM) and optical microscopy respectively. Experimental results show that the friction and wear properties of the PTFE composites can be greatly improved by liquid paraffin lubrication. The wear of these PTFE composites can be decreased by at least 1 to 2 orders of magnitude compared with that under dry friction conditions, while the friction coefficients can be decreased by 1 order of magnitude, SEM and optical microscopy investigations of the rubbing surfaces show that metal fillers of Cu, Pb and Ni not only raise the load carrying capacity of the PTFE composites, but also promote transfer of the PTFE composites onto the counterfaces, so they greatly reduce the wear of the PTFE composites. However, the transfer of these PTFE composites onto the counterfaces can be greatly reduced by liquid paraffin lubrication, but transfer still takes place.     

Microstructure of PTFE-Based Polymer Blends and Their Tribological Behaviors Under Aqueous Environment

Four polytetrafluoroethylene-based polymer blends (PTFE blends) with polyimide (PI), polyether ether ketone (PEEK), poly(phenyl p-hydroxybenzoate) (PHBA), and perfluoroethylene propylene copolymer (FEP) were prepared by compression molding and follow-up sintering. Their microstructure was observed by scanning electron microscope. And the tribological behaviors of PTFE blends sliding against 316 steel under pure water and sea water lubrication were comparatively evaluated using block-on-ring tribology test rig. The worn surface of counterpart was examined by X-ray photoelectron spectroscopy. The results showed that by blending with the four polymers, PTFE exhibited the transformed microstructure and improved wear resistance. Compared with FEP, rigid polymers PI, PHBA, and PEEK can enhance the wear resistance of PTFE greatly because they can effectively improve the load-carrying capacity of PTFE matrix and can more efficiently prevent the crystalline bands of PTFE from being pulled out. However, because of the weak inhibition on the pulling out of PTFE crystalline bands, FEP cannot enhance the wear resistance of PTFE as significantly as other polymers. In addition, the friction coefficients and wear rates of PTFE and its blends were lower under the lubrication of sea water than under the lubrication of pure water, which was ascribed to more excellent lubricating effect of sea water originating from the deposition of CaCO₃ and Mg(OH)₂ onto the sliding surfaces.     

Tribological Interaction of Plasma-Functionalized Polytetrafluoroethylene Nanoparticles with ZDDP and Ionic Liquids

Polytetrafluoroethylene (PTFE) nanoparticles were coated with consecutive plasma deposited siliceous and methacrylate coatings. Secondary zinc dialkyldithiophosphate (ZDDP), phosphonium cation and phosphate anion ionic liquid (IL), and IL with phosphonium cation and dithiophosphate anion were mixed with the functionalized nanoparticles. Tribological studies were carried out for seven separate formulations including base oil, oils with only additives, and oils with additives and functionalized PTFE particles. Results indicate strong synergistic interactions of ZDDP and ILs with functionalized nanoparticles providing enhanced friction and wear performance. Chemical analysis of the tribofilms using X-ray photoelectron spectroscopy and X-ray absorption near edge structure spectroscopy indicates functionalized PTFE nanoparticles interact synergistically with ZDDP and ILs to form silicon- and fluorine-doped tribofilms resulting in superior tribological performance.     

Tribological properties of P‐ and N‐containing organic compounds as potential extreme‐pressure and antiwear additives

An amine salt of an alkoxylphosphate (a P‐ and N‐containing organic compound, PN) was synthesised. Its extreme‐pressure, antiwear, and friction‐reducing properties were evaluated as an additive in liquid paraffin and a mineral oil. Tests were performed on a four‐ball friction and wear tester with an AISI 52100 steel ball self‐mated pair and the results were compared with those of sulphurised olefin (SO), zinc di‐n‐butyldithio‐phosphate (ZDDP), and dibutylphosphite (DBP). The morphologies of the worn steel surfaces were observed using a scanning electron microscope, while the binding energies of some typical elements on the worn surfaces were determined using X‐ray photoelectron spectroscopy. The additives were found to increase the load‐carrying capacity and to reduce wear and friction coefficient considerably. PN as an additive exhibits better load‐carrying, antiwear, and friction‐reducing properties than SO, ZDDP, and DBP under the same test conditions.     

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.     

Tribological characteristics of greases with and without metallo-organic friction-modifiers

ABSTRACT

An important focus of grease development is to minimize friction and wear while improving load bearing capacity. ASTM D2266 test method is commonly used to evaluate performance of grease at 75°C, 40?kg and 1200?rpm for 1 hour. However, actual applications may require bearings to be subjected to cyclic loading and variable frequency conditions wherein rotations per minute (rpm), load and duration of test are variables. Five different blends of greases were formulated using ZDDP (3?wt.%), PTFE (2?wt.%), MoDTC (2?wt.%), combination of ZDDP/PTFE in a weight ratio of 3:2 and a combination of ZDDP/PTFE/MoDTC in 3:2:2 weight ratios. They were tested under ASTM D2266 test method as well as under cyclic loading and variable frequency conditions where loads, frequency and duration of the tests were treated as variables. It was found that the combination of ZDDP/PTFE/MoDTC results in significant improvement in the wear and friction under cyclic loading as well as ASTM D2266 test conditions. It was also demonstrated that MoDTC accelerated the tribochemical degradation of ZDDP that resulted in the formation of a protective tribofilm layer on the interacting surfaces. The analysis of the tribofilm formed indicated that when MoDTC was used together with ZDDP and PTFE, a combination of MoS₂, phosphates and sulfates of Zn and Fe are formed whereas when only ZDDP and PTFE was used the tribofilms were largely composed of phosphates and sulfates of Zn and Fe.     

Tribological studies of poly(ether ether ketone) blends

A review of friction and wear studies of poly(ether ether ketone) (PEEK) blended with other polymers is presented. PEEK is a high performance thermoplastic now commonly employed in many engineering applications, but its tribological properties deteriorate in high temperature environments. One approach to improving the friction and wear properties of PEEK is to blend this plastic with appropriate polymers. In recent years, a number of investigations into the tribology of PEEK blended with poly(ether imide) (PEI), polytetrafluoroethylene (PTFE) and liquid crystalline polymers (LCPs) have been reported and these studies are discussed.     

Tribology of polymers

Tribological studies were performed on the friction and wear behaviour of polymers under conditions of dry sliding. The investigations were carried out with thermoplastics suitable for practical applications, eg HDPE, PP, PTFE, PA 6, PA 66, POM, PETP, PBTP, PI, as well as with some filled and reinforced polymers and composite materials. For polymer-polymer sliding pairs, the experimentally determined friction values could be related to the surface energies of the material pairings. In the case of polymer-metal sliding pairs, a relationship between the combined interfacial stresses and the rupture strength of the polymers was found. In addition to the review of correlations between the tribological behaviour of thermoplastics and material properties, the dependency of wear and friction on surface roughness, sliding velocity and contact pressure for various filled polymers is described.