Tribological Properties of MoSi2 Against AISI10045 Steel Under Sliding Friction

MoSi2 samples were prepared by a self-propagating high-temperature synthesis （SHS） and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1） oil lubrication can obviously improve the tribological properties of MoSi2, 2） the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3） with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4） under oil lubrication the wear mechanism is mainly fatigue pitting.     

GF增强尼龙1010复合材料的磨擦学性能研究

制备了玻璃纤维（GF）增强尼龙1010复合材料,在环一块磨损试验机上研究了复合材料的摩擦学性能。结果表明：GF含量对复合材料的摩擦学性能有显著影响,GF质量分数为35％时增强效果较好;随着滑速的增加,GF增强尼龙1010复合材料的摩擦系数和磨损量持续上升。干摩擦下的复合材料磨损以疲劳断裂和粘着为主,且纤维出现磨损、断裂及从基体中剥落的现象。在油润滑下材料向对偶产生轻微的转移,与干摩擦相比复合材料的摩擦系数和磨损量大为降低;水润滑下的尼龙以化学腐蚀磨损和磨粒磨损为主,此时复合材料摩擦系数也有较大程度的降低,但磨损量较干摩擦增大。     

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.     

紧固件表面锰系磷化膜的制备及摩擦磨损性能

为了提高核主泵紧固件的摩擦磨损性能,采用三种磷化工艺在40Ni Cr Mo7钢表面制备了锰系磷化膜.采用多功能材料表面性能测试仪进行了往复摩擦磨损试验,并研究了在有无润滑条件下,不同工艺对磷化膜摩擦磨损性能的影响.采用扫描电子显微镜和能谱仪表征了磨损前后磷化膜表面的组织形貌和化学成分,并分析了其磨损失效机制.结果表明,通过工艺Ⅱ制备的磷化膜具有最优的摩擦磨损性能.磷化膜特有的孔隙结构具有储油能力,有利于改善其摩擦学性能.随着法向载荷的增加,磷化膜的塑性变形增大,抗剪切强度降低,且摩擦系数呈先缓慢下降后急剧上升的趋势.     

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     

Tribological behavior of MC Nylon6 composites filled with glass fiber and fly ash

To improve tribological property of MC Nylon6,the glass fiber and fly ash reinforced monomer casting nylon composites(GFFAPA)were prepared by anionic polymerization of ε-caprolactam.The friction and wear behaviors of composites under dry condition,water lubrication and oil lubrication were investigated through a ring-black wear tester.Worn surfaces were analyzed using a scanning electron microscope.The experimental results show that the tensile strength and hardness of nylon composites are obviously improved with reinforcement increasing.Compared to MC nylon,the lowest friction coefficient and wear rate of glass fiber reinforced nylon composites(GFPA)with GF30% respectively decrease by 33.1% and 65.3%,of fly ash reinforced nylon composites(FAPA)with FA20% decrease by 5.2% and 68.9% and of GFFAPA composites with GF30% and FA10% decrease by 57.8% and 89.9%.The main wear mechanisms of FAPA composites are adhesive and abrasive wear and of GFPA composites with high proportion are abrasive and fatigue wear.The worn surfaces of GFFAPA composites are much multiplex and the optional distributing glass fiber and fly ash have a synergetic effect on the wear resistance for GFFAPA composites.Compared with dry friction,the friction coefficient and wear rate under oil lubricated conditions decrease sharply while the latter reversely increase under water lubricated conditions.The wear mechanisms under water lubricated condition are principally chemical corrosion wear and abrasive wear and they become boundary friction under oil lubricated condition.     

基于乳化液的ZCuPb20Sn5和ZL108摩擦磨损特性研究

为了考察ZCuPb20Sn5和ZL108在乳化液润滑条件下的摩擦磨损性能,在MMW-1摩擦磨损试验机上对两种材料进行了销盘摩擦副和止推圈摩擦副的试验研究,得出了在不同载荷和转速下,两种材料的磨损量、磨损率、摩擦力及摩擦系数等实验结果,采用MATLAB三次样条拟合工具分别得出了摩擦系数和磨损率与载荷和速度之间的关系曲线,用扫描电子显微镜对摩擦面进行了观察分析。结果表明,ZCuPb20Sn5比ZL108更适合于乳化液润滑条件下使用。     

Tribological properties of nanostructured n-Al_2O_3/Ni coatings deposited by plasma spraying

1INTRODUCTION Nanostructuredmaterialsareofprimeinterestsincetheyshouldexhibitsuperiorpropertiesin comparisonwithconventionalmaterials(i.e.mi crostructured).Thermalsprayingisregardedasoneofthepossiblemethodstodepositnanostruc turedcoatings.Researchworkshav…     

Friction and wear performances of cathodic arc ion plated TiAlSiN coating under oil lubricated condition

TiAlSiN coating was deposited on H13 hot work mould steel using cathodic arc ion plating (CAIP). The surface-interface morphologies and phases of the obtained coating were analyzed using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), respectively, and the morphologies, distributions of chemical elements and profiles of worn tracks were also researched using scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and optical microscope (OM), respectively. The friction-wear performances of TiAlSiN coating under oil lubricated and dry fiction conditions were investigated, and the wear mechanisms of TiAlSiN coating were discussed. The experimental results show that the coating is primarily composed of (Ti, Al)N, AlTiN, and TiN hard phases, Si₃N₄ exists between the (Ti, Al)N crystal grains, increasing the coating microhardness to 3200HV. The TiAlSiN coating has excellent performances of reducing friction and wear resistance, the average coefficient of friction (COF) of TiAlSiN coating under oil lubricated condition is only 0.05, lowered than the average COF of 0.211 under dry friction condition, the wear rate decreases by about 81.2% compared with that under dry friction condition. The wear mechanism of TiAlSiN coating under oil lubricated and dry friction conditions is composed of abrasive wear, fatigue wear, and abrasive wear, respectively. The internal friction of oil lubrication is a main factor of decreasing fatigue wear.     

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。     

不同工况下丁腈橡胶的摩擦磨损机理

为了合理选择螺杆泵定子橡胶材料以提高螺杆泵的使用寿命,分析了不同工况下丁腈橡胶与金属配副的摩擦磨损机理.采用MPV-600环块式摩擦磨损试验机对不同炭黑质量分数的丁腈橡胶在变载荷情况下进行摩擦磨损试验,利用体视显微镜观察橡胶磨损后的表面形貌,使用红外光谱仪分析表面官能团变化.试验结果表明:干摩擦情况下,磨损量在一定炭黑质量分数范围内随其增加而减小,磨损机制为黏着磨损和磨粒磨损;水润滑情况下,由于水的润滑及冷却作用,炭黑质量分数适中的橡胶耐磨性最好,磨损机制为磨粒磨损;原油润滑低载荷情况下,磨损量几乎不受炭黑质量分数的影响,而高载荷情况下,炭黑质量分数越高,磨损量越小,其磨损机制以腐蚀磨损为主.     

负泊松比超构材料摩擦学性能研究

负泊松比超构材料因其优异的性能而被广泛应用于各工程领域。本文针对负泊松比超构材料的摩擦学性能,以丙烯腈-丁二烯-苯乙烯（ABS）材料为载体,基于典型内凹六边形负泊松比结构,利用熔融沉积成型3D打印技术制备了负泊松比（Negative Poisson''s Ratio, NPR）试样和实体试样,结合环-块摩擦磨损试验、扫描电子显微镜、白光共焦三维形貌仪以及有限元静力学应力应变分析等测试手段,对比研究了不同载荷（10、30、50 N）工况下NPR试样与实体试样摩擦学性能的差异性。研究结果表明：1）不同载荷下,NPR试样的应力与变形大于实体试样,且随着载荷增加,NPR试样内部单元的关节处出现应力,负泊松比效应更加明显;2）相同载荷下,NPR试样的摩擦系数较小,磨损量较大,且摩擦接触界面出现犁沟,基体产生磨粒磨损,随着载荷的增加,部分磨屑粘着在NPR试样摩擦表面,磨损机理转变为粘着磨损;3）在较大载荷（本滚动试验条件下为50 N）下,NPR试样负泊松比效应增强,发挥出更好的减振抗冲击性能和能量吸收与传递作用,相比于低载荷（30 N）,摩擦系数减小,磨损量降低,有利于提高试样的摩擦学性能。研究成果丰富和完善了负泊松比摩擦学材料的研究体系,在材料科学研究前沿进行探索性尝试,为负泊松比材料在摩擦学工程领域应用提供基础数据和技术支撑。     

固体润滑块及其减摩性能的研究

研究了钢轨和轮箍间的减摩材料--固体合成润滑块及其减摩性能.试验结果表明固体合成润滑块与32#轴油相比较,具有摩擦系数小、磨损率低、磨损量小、磨痕深度浅、粗糙度低、磨粒尺寸小等优点,而且强度高、极限负荷大,是延长钢轨和轮箍寿命,提高机械效率,节约能源的一种良好润滑材料.     

模拟活塞缸套摩擦副的仿生非光滑表面的摩擦学研究

根据仿生学原理,利用铝合金活塞和铸铁汽缸套的材料设计了普通结构和几种仿生结构的摩擦副,并在摩擦磨损试验机上进行了对比试验。结果表明,在干摩擦时,非光滑结构与普通结构的摩擦副的摩擦性能差异不大。在沾油润滑条件下,仿生非光滑结构的摩擦副的抗黏着磨损性能明显优于普通结构。其原因是在有润滑条件时,仿生非光滑结构具有较强的贮存润滑油及形成油膜的能力。     

TC4钛合金表面微织构干摩擦特性

为改善TC4钛合金表面摩擦学性能,采用皮秒紫外激光技术在TC4钛合金表面加工了3种形状的微织构。使用多功能摩擦磨损试验机研究了织构化TC4钛合金在多接触条件下的摩擦学特性,并采用显微硬度仪、扫描电镜、激光共聚焦显微镜对织构化TC4钛合金的表面硬度、表面粗糙度、磨痕三维轮廓和磨痕形貌等进行分析。结果表明,织构化TC4表面硬度提升约60%,其中三角形凹坑织构表面综合硬度最高;微织构能有效降低TC4表面接触过程的摩擦系数,其中圆形与矩形织构摩擦系数最低,较无织构表面减少约10%;微织构能捕获磨屑,减少磨粒磨损,提高耐磨性能,相同接触条件下,织构化试样磨损量减少了50%;当载荷一定时,速度增加可使织构化TC4表面摩擦系数降低;当摩擦速度一定时,载荷降低可导致织构化TC4表面摩擦系数降低。本研究可为提升钛合金表面摩擦学性能提供研究思路,减少钛合金因摩擦磨损造成的损失与事故。     

Tribological Behavior of Nano-ZrO_2 Reinforced PTFE-PPS Composites

Polytetrafluoroethylene(PTFE) is a commonly used seal material for oil-free engine that is well known for its excellent tribological properties. In this work, the nano-ZrO_2 particles were used as the friction modifiers to improve the friction and wear performance of PTFE-PPS composites. The friction and wear characteristics of PTFE/PPS-nano-ZrO_2 composites were investigated by a block-on-ring tester under dry friction sliding condition. The worn surfaces, counterpart transfer films and wear debris were studied by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the increase of nanoZrO_2 content could effectively reduce the coefficient of friction and enhance the anti-wear ability of PTFEPPS composites. Especially, the best tribological properties of the composites were obtained when the particle content of nano-ZrO_2 was 10 vol%, the anti-wear performance of composite is 195 times better than that of the unfilled PTFE-PPS composite. Under different conditions, the coefficient of friction of PTFE/PPS-nano-ZrO_2 composites was more affected by the applied load while the wear rate was more affected by the sliding velocity.     

Mechanical and Tribological Properties of CrN Coated Inconel X750

Three CrN coatings were deposited on the Inconel X750 through the metal vapor vacuum arc ion implantation and the magnetic filtered cathodic vacuum arc deposition system(MEVVA-FCVA) with the N_2 flow rates of 10, 50, and 100 sccm, respectively. The surface morphologies and cross-section morphologies of the CrN coatings were obtained through scanning electron microscopy(SEM) and an optical profilometer.The microstructures of the coatings were characterized through X-ray diffraction(XRD). The hardness and the elastic modulus of the coatings were tested by a nano-hardness tester. The adhesion strength and friction coefficients were investigated through scratch tests and ball-on-disk tests and the wear tracks were tested by the optical profilometer. The experimental results indicate that the CrN coating deposited on the Inconel X750 substrate displays a uniform thickness and a smooth surface. The mechanical properties behaves well as the N_2 flow rate varies. The CrN coating significantly reduces the friction coefficient fluctuation and improves the antiadhesion and anti-wear properties of the Inconel X750.     

锻造和铸造CoCrMo合金的摩擦学性能研究

选用医用锻造和铸造CoCrMo合金材料,利用UMT-II型摩擦磨损试验机,综合考察并比较了不同载荷条件下,25%小牛血清润滑时的摩擦磨损性能,分析了磨损机理.实验结果表明：锻造和铸造CoCrMo合金的物相主要由α-CoCr和ε-CoCr固溶体相组成.锻造合金含有较高的α-CoCr相,铸造合金则含有较高的ε-CoCr相,锻造合金的显微硬度略高于铸造合金.25%小牛血清润滑条件下,不同载荷条件下锻造和铸造CoCrMo合金的摩擦系数具有相同的变化规律.低载荷时,锻造CoCrMo合金的摩擦系数略高于铸造合金,高载荷时,二者的摩擦系数相当.锻造和铸造CoCrMo合金的磨损皆为混合磨损机制,即犁沟磨损为主,并伴有磨粒磨损和疲劳磨损.     

Tribological properties of nanostructured n -Al2O3/Ni coatings deposited by plasma spraying

Nanostructured n-Al₂O₃/Ni feedstock for thermal spraying was manufactured by the method of chemical wrapping and spray drying. The nanostructured coating was sprayed with this feedstock. Tribological properties of the coatings and steel 45# were tested. Within the testing range, the friction coefficient of coatings against GCr15 steel decreased and the mass loss of coatings increased at first then decreased with the increase of load. Under each load, the coatings’ fraction coefficients and wear losses were lower lower than that of steel 45#. Scanning electron microscopy and energy dispersive spectrometer analysis show that adhesion is the dominating wear mechanism, and fatigue exists at the same time. Material transferred from counter-part to the coating is the main factor which influences the coatings’ friction coefficient and wear losses.     

Effect of Salt Spray Corrosion on Tribological Properties of HVOF Sprayed NiCr-Cr_3C_2 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-Cr_3C_2 coating with intermediate layer. Ni-Zn-Al_2O_3 coatings as interlayers were prepared by low pressure cold spray(LPCS) between NiCr-Cr_3C_2 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.