Comparison of the Wear Behavior of UHMWPE Lubricated by Human Plasma and Brine

The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-directional sliding motions. The worn surface and wear particles produced in these two lubricants were analyzed. Sliding motion pattern affected the friction coefficients lubricated with plasma, while seldom affected that lubricated with brine. UHMWPE lubricated with plasma showed about half of the wear rate of that lubricated with brine. The two rates were 0.75 pg/m and 2.19 pg/m for the two motion patterns, respectively. However, wear particles generated in plasma included a greater amount of small particles, compared to that in brine. In uni-directional reciprocation, the main wear mechanism is ploughing both in plasma and in brine. In bi-directional sliding modes, the significant characteristic is ripples on the worn surface in plasma, while there are oriented fibers on the worn surface in brine.     

纳米填料增强UHMWPE–橡胶水润滑摩擦学性能

为了研究水润滑条件下试验载荷和速度对纳米填料（Nano-SiC）改性超高分子量聚乙烯（UHMWPE）/橡胶复合材料摩擦学性能的影响,通过高温混炼、热压成型制备Nano-SiC辅以聚四氟乙烯（PTFE）填充改性UHMWPE/橡胶复合材料。采用MRH-3型环-块摩擦实验机探究四种不同载荷条件下改性复合材料的摩擦磨损性能,采用光学显微镜（OM）、扫描电子显微镜（SEM）和非接触光学三维轮廓仪对试样微观磨损表面形貌分析,从微观层面探究改性复合材料的摩擦机理。试验结果表明：在定载变速条件下,速度由0.02m/s升到3.59m/s时,改性复合材料的动摩擦系数波动幅度与静摩擦系数均呈现大幅下降趋势,粘-滑现象（Stick-Slip Phenomenon）减弱,摩擦系数波动归于平稳;试验载荷和纳米粒子含量的变化与试样摩擦磨损程度呈负相关,在水润滑条件下,随着纳米粒子含量增加,摩擦系数与磨损率均出现明显降低,填充比例为5%的复合材料摩擦学性能最佳,摩擦系数整体较UHMWPE/橡胶材料降低35%,磨损率降低46.6%,磨损表面形貌也随之发生改变;随着载荷的增加,复合材料的磨损率从1.25×10-6mm3/(Nm)降至0.4×10-6mm3/(Nm)。Nano-SiC的含量与工况载荷压力对摩擦磨损均存在一定影响,即填充适量Nano-SiC的UHMWPE/橡胶复合材料与一定工况压力下的对偶钢环组成的摩擦配副能改善摩擦环境,减轻粘-滑现象,有利于减小材料的磨损。     

Biotribological behavior of ultra high molecular weight polyethylene composites containing bovine bone hydroxyapatite

Wear particles of ultrahigh molecular weight polyethylene (UHMWPE) are the main cause of long-term failure of total joint replacements. Therefore, increasing its wear resistance or bioactivity will be very useful in order to obtain high quality artificial joints. In our study, UHMWPE composites filled with the bovine bone hydroxyapatite (BHA) were prepared by the method of compression moulding. A ball-on-disc wear test was carried out with a Universal Micro-Tribometer to investigate the friction and wear behavior of a Si3N4 ceramic ball, cross-sliding against the UHMWPE/BHA composites with human plasma lubrication. At the same time, the profiles of the worn grooves on the UHMWPE/BHA surface were scanned. The experimental results indicate that the addition of BHA to UHMWPE had a significant effect on the biotribological behavior of UHMWPE cross-sliding against the Si3N4 ceramic ball. The addition of BHA powder enhanced the hardness and modulus of elasticity of these composites and decreased the friction coefficients and wear rates under conditions of human plasma lubrication. When the added amount of BHA powders was up to 20%～30%, UHMWPE/BHA composites demonstrated the designed performance of the mechanical properties and biotribological behavior.     

Friction and Wear Behavior of GCr15 Under Multiple Movement Condition

1 IntroductionThe friction and wear behavior of metals underuni-directional sliding has been widely studied eitherby ball-on-disc or by block-on-ring test machines[1].In practical applications, however, we will usuallymeet cross-sliding condition. For example, compositefretting wear of a ball on disc includes the tangentialfretting and the radial fretting [2] .Zhu et al[3-4] stud-ied the composite fretting wear behaviors of GCr15bearing steel and 7075 aluminum alloys. In slidingbearing, the …     

Tribological properties of SiC/Cu composite at high temperature

SiC/Cu composites were prepared by hot pressing. The high temperature tribological properties of the composites were investigated. XRD, SEM techniques were carried out to characterize the samples. It is found that the friction coefficient of SiC/Cu composites increases with the increasing SiC content. The SiC reinforcement particles are worn down other than removed by pulling out during the wear test. Oxidation of Cu debris leads to the smooth contacting surface. Ring crack is formed under the cyclic wear test. The crack propagates through the damaged matrix and along the brittle interface between SiC particles and Cu matrix.     

Comparison of Biotribology of Swine Compact Bone Against UHMWPE

A pin-on-disk tribometer was used, in a comparative test to observe the tribological behavior of the swine femoral bone against UHMWPE with dry friction, physiological water and human plasma lubrication. The wear mechanisms of swine bones and UHMWPE were investigated by SEM. The experimental results of these wear tests demonstrated that both the friction coefficient and wear rate of UHMWPE were the lowest when human plasma lubrication was used. The wear mechanism of the compact bone was mainly fatigue wear with dry friction, corrosive wear under physiological water lubrication and abrasive wear with human plasma lubrication. For UHMWPE, the wear mechanism was adhesive wear and plastic deformation with dry friction, serious ploughing and fatigue fracture wear under physiological water lubrication, fine ploughing and plastic deformation with human plasma lubrication. An analysis of nitrogen elements on the wear surface of UHMWPE indicated that the content of nitrogen in worn areas was 16 times higher than that in unworn areas, which proved that serum protein deposition occurred on worn areas.     

添加微细铬铁粉对烧结钢摩擦磨损性能的影响

研究了加入不同含量的微细铬铁粉对烧结钢干摩擦磨损性能的影响,并借助于扫描电镜观察分析其磨损形貌,探讨摩擦磨损机制。研究结果表明:添加微细铬铁粉可改善烧结钢的强度、硬度和摩擦磨损性能,铬的质量分数为1.5%时,耐磨性最佳。磨损造成一定厚度的塑性变形,硬度较高的材料塑性变形层较薄。磨损早期,磨粒磨损是主导机制,磨损后期,由于塑性变形导致亚表层产生裂纹,进而发生的剥层磨损是主导磨损机制。     

Preparation of tungsten disulfide motor oil and its tribological characteristics

Through using mineral oil and synthetic oil to deploy the semisynthesis base oil, modifying the surfaces of ultrafine tungsten disulfide grains by surface chemical embellishment and adsorption embellishment to make them suspended steadily in the base oil as solid lubricating additive, and adding some function additives, the tungsten disulfide motor oil was prepared. The tribological characteristics of this kind motor oil and the well-known motor oils in our country and overseas were studied. The results show that the oil film strength of this kind of motor oil is respectively 1.06 and 1.38 times of that of shell helix ultra motor oil and great wall motor oil, and its sintering load is 1.75 and 2.33 times of that of them, and when tested under 392 N, 1 450 r/min and 30 min, the friction coefficients of friction pairs lubricated by the tungsten disulfide motor oil decrease with the increase of time, meanwhile, the diameter of worn spot is small, and the surface of worn spot is smooth, and no obvious furrows appear. The experiments indicate that the tungsten disulfide motor oil has the better antiwear, antifriction and extreme pressure properties than the well-known motor oils.     

High temperature tribological behaviors of nano-diamond as oil additive

The tribological behaviors of the nano-diamond particles including the nano-diamond and the nano-diamond modified were studied at high temperature using SRV multifunctional test system. The worn steel surfaces were analyzed by means of X-ray photoelectron spectroscopy (XPS). The results show that nano-diamond particles can obviously improve the antiwear and friction reducing properties of the base oil at high temperature and the high load. The friction coefficient of the nano-diamond is very low at 200 °C when the test load is not more than 20 N. This tribological behaviors should attributed to the similarly to “ball bearing” lubrication action of the nano-diamond particles, so the movement between tribological pairs become sliding/rolling. The nano-diamond modified by dimer ester possesses excellent antiwear and friction reducing performance at 500 °C and load 500 N. The tribochemical reaction film between the nano-diamond particles and the renascent wear surface plays dominating lubrication role and the presence of the dimer ester on the rubbing surface can be propitious to form lubrication film containing nano-diamond on the worn surface at high temperature and high load. Foundation item: Project (51489020605JS9105) supported by National Key Laboratory for Remanufacturing     

硼酸盐添加剂的抗磨机理研究

通过在环块式磨损试验机和点接触摩擦磨损试验机上对加入硼酸盐添加刘的润滑油进行了边界润滑下摩擦学参数的测量和分析,并用俄歇电子能谱(AES)对磨痕表面进行了元素成分及其相对原子浓度比的分析,证实了硼酸盐添加剂具有较小的减摩作用和良好的抗磨性能;发现磨痕表面元素的相对原子浓度比随着摩擦条件的变化而变化。研究认为,硼酸盐添加剂的抗磨性能主要是由于硼酸盐粒子吸附和/或沉积在金属表面上的微球润滑层和易在表面生成化学反应膜所引起。     

Design of wear-out-failure in-situ repair parts by environment-friendly nanocopper additive

Oleic acid surface-modified Cu nanoparticles with an average size of 20 nm were prepared by liquid phase reducing reaction. The tribological performance and mechanism of nanocopper as additive were studied by means of tribotester, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation instrument. The results indicate that the modified nanocopper additive can significantly improve the wear resistance and reduce friction coefficient of base oil. A copper protective film is formed and contributes to the excellent tribological properties of nanocopper additive. On the basis of the film forming mechanism, a new in-situ repair method was designed and used to repair wear-out-failure injection pump plunger and barrel. Furthermore, the current research progress of nanoparticles as green energy-saving lubricating oil additives were presented.     

Effect of salt spray corrosion on tribological properties of HVOF sprayed NiCr-Cr<Subscript>3</Subscript>C<Subscript>2</Subscript> coating with intermediate layer

The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr₃C₂ coating with intermediate layer. Ni-Zn-Al₂O₃ coatings as interlayers were prepared by low pressure cold spray (LPCS) between NiCr-Cr₃C₂ cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.     

Synthesis of γ-AlOOH Nanoparticle and Its Tribological Properties as Additives in Liquid Paraffin

An experiment procedure was presented for the synthesis of γ-AlOOH nanoparticles by a dehydration process which employed the solution of H₂O₂ as dehydrator. The phase and morphology of the product were investigated by XRD and TEM. The tribological properties of γ-AlOOH nanoparticles with the average diameter of 15?nm as additives in liquid paraffin were investigated by a four-ball tester, and the worn surfaces were analyzed by SEM and EDS. Results show that the average size of synthesized γ-AlOOH nanoparticles increases with the increase of the pH value and temperature of the reactant. The γ-AlOOH nanoparticles as additives could exhibit good tribological properties due to their covering effect, which prevents the direct contact of asperities and reduces the adhesion. As the real area of contact decreases with the decrease of applied load, the optimum concentration varies from 0.4% to 0.1% when the applied load decreases from 294?N to 200?N.     

The Friction and Wear of Sleeve-ring Pair Lubricated by Active Lubricants in the Presence of Magnetic Field

1　IntroductionTribologicalphenomenoncanbeseenintheopera tionsofequipments ,instruments ,units ,andsoon .Theinvestigationonthemagnetictribologyattractsbroadinter estsoftribologicalworkers ,andthesignificantexplorationsonthetheoreticalandapplicationhavecarriedout .Thefrictionreductionandwearpreventioninthepresenceofmagneticfieldareconsideredtobetheincreaseofmicro hardnessontherubbingsurfaceandtheoxidationofoxy genonthewearsurfaceatthedryfrictionofatmosp here[1 4] .Theperformanceofboundarylubric…     

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。     

Tribological Properties of PVA-H Composites Reinforced by Nano-HA Particles

The friction and wear behaviors of tribological mechanical components were studied on a four-ball tester under dry conditions, and the wear mechanism was analyzed by observed worn surface using a scanning electron microscope （SEM）. It was found that the friction and wear properties were improved by the addition ofnano HA particles. The composite containing 1 wt% nano HA had the optimum friction coefficient. It is also found that the addition of nano HA increases the wear resistance of oure PVA-H and PVA-H composites.     

桥联环三磷嗪用作润滑油添加剂的摩擦学特性

合成了一种桥联环三磷嗪化合物,通过核磁共振磷谱（31P-NMR）和傅立叶变换红外光谱对其结构进行了表征.用Optimal SRV型摩擦磨损试验机考察了其作为季戊四醇酯（PET）添加剂对钢/钢的摩擦学性能.研究结果表明,作为高温润滑油添加剂,与[四（3-三氟甲基苯氧基）-二（4-氟苯氧基）]环三磷嗪（X-1P）相比,合成的桥联环三磷嗪（L-2P）具有更为优良的摩擦学性能.通过对钢球的磨损表面进行扫描电子显微镜和X-射线光电子能谱仪分析,发现桥联环三磷嗪在摩擦中与摩擦副表面发生了复杂的摩擦化学作用,形成了含FeF2等物质组成的边界润滑膜.     

PTFE和MoS_2填充尼龙复合材料摩擦行为研究

以注塑成型法制备了聚四氟乙烯(PTFE)和MoS2填充PA1010复合材料,采用M-2000磨损试验机考察了复合材料与45钢对摩时的摩擦磨损性能,并利用扫描电子显微镜(SEM)分析了PA复合材料磨损表面及其偶件表面转移膜形貌。研究结果表明:PTFE填充PA1010可显著改善尼龙复合材料的摩擦磨损性能。PTFE质量分数为25%时,复合材料的摩擦学综合性能最佳。PTFE和MoS2共同填充PA1010时,复合材料的摩擦因数和磨损率随着PTFE含量的减少、MoS2含量的增加,整体呈现增大趋势,其中PA+20%PTFE+5%MoS2复合材料的减摩抗磨性能较好。在正常工作条件下(0.21-0.42 m/s,100-300 N),PA+25%PTFE复合材料的抗磨性优于相同条件下PA+20%PTFE+5%MoS2复合材料,但PA+20%PTFE+5%MoS2复合材料具有更宽的速度适用范围。PA复合材料的摩擦磨损性能与其在偶件表面形成的转移膜的特性有重要关系,转移膜的厚度大小、分布均匀状况以及和偶件的结合强度都会对复合材料的减摩抗磨性能产生影响。     

Tribological properties of TiAl-Ti3SiC2 composites

The tribological properties of TiAl-Ti_3SiC_2 composites （TMC） against Si_3N_4 ceramic ball pair at room temperature were investigated through the determination of friction coefficients and wear rates, and the morphologies and compositions of wear debris, worn surfaces of TMC and Si_3N_4 ceramic ball were analyzed. The experimental results showed that TMC with 15wt% Ti_3SiC_2 exhibited relatively excellent tribological properties. The solid-phase self-lubricating tribo-layers formed on the worn surfaces of both TMC with 15wt% Ti, SiC, and Si,NA ceramic ball, which was beneficial to the lower friction coefficient and wear rate.     

Assessment model for tribological property of ceramic/stainless steel rubbing pairs in H2O2 solution

The tribological properties of ZrO2 ceramic and 1Cr18Ni9Ti stainless steel rubbing pairs were investigated using a special tribo-tester under different concentrations of hydrogen peroxide (H2O2) solution.The comparison analyses of the friction coefficients,worn volume rates,worn particles and surface roughness were conducted under the tested conditions.There were significant differences of the tribological properties of the rubbing pairs in the different concentrations H2O2 solution because of oxidation and corrosion.This research has revealed that the main wear mechanisms between the rubbing pairs are severe adhesive wear,abrasive wear and corrosive wear in the H2O2 solution with different concentrations.A model has been established to assess the most suitable concentration of the H2O2 solution for the tribological properties of the rubbing pairs.The result shows that 50% concentration of the H2O2 solution is the most suitable.The assessment result is consistent with the experimental result.It is believed that the knowledge gained in this study is useful for the optimization of the friction pairs in the extreme condition.