火焰喷涂PA1010/n-SiO2复合涂层干摩擦磨损性能

利用火焰喷涂法制备PA1010/n-SiO2复合涂层,并采用均匀试验设计方法研究涂层在干摩擦条件下同GCr15 钢环配副时的摩擦学性能;利用SPSS 12.0统计软件对试验结果进行回归分析, 建立涂层摩擦系数和磨损质量损失同pv值 (摩擦载荷与摩擦速度的乘积)相关性的数学模型;利用示差扫描量热仪(Differential scanning calorimetry, DSC)和扫描电子显微镜(Scanning electron microscope, SEM)对复合涂层的热性能和磨损表面形貌进行分析。结果表明,n-SiO2的加入能明显提高涂层的结晶性能、耐磨性能。当n-SiO2含量为1.5%时,复合涂层摩擦磨损性能最佳,在试验条件下磨损质量损失降低近4倍,摩擦因数降低23％,跑合期缩短44％,复合涂层与GCr15钢环对磨时的磨损机理主要为疲劳磨损和轻微的粘附 磨损。     

润滑油缺失工况下不同活塞环涂层对缸套摩擦磨损对比研究

为研究润滑油缺失工况下不同活塞环涂层在不同温度下与缸套的摩擦学性能,选取5种商用活塞环涂层,利用扫描电子显微镜观察不同涂层的截面形貌,利用往复式摩擦磨损试验机,在润滑油缺失工况下,分别在常温、200 ℃和350 ℃条件下进行摩擦磨损试验,利用轮廓仪和光学显微镜分别观察摩擦试验后的磨损量和磨痕形貌。结果表明：CrN基涂层和CKS涂层主要为黏着磨损,对缸套磨损大,不同温度下摩擦学性能稳定;含DLC涂层主要为磨料磨损,常温摩擦因数小,高温下不同涂层有较大差异,其中CDC+DLC涂层综合性能最佳。     

粘结固体润滑涂层在油润滑条件下的摩擦学性能

为了探讨粘结MoS2基固体润滑涂层在油润滑条件下的抗磨减摩性能,采用MHK-500型摩擦磨损试验机对粘结MoS2基固体润滑涂层在4种常用油(液体石蜡、RP-3煤油、4050滑油和CD-40柴油)润滑下的摩擦磨损性能进行了研究,考察了速度和载荷对润滑涂层在4种不同的常用油润滑下的摩擦磨损性能。结果表明,在低载荷(320N)试验条件下,4种常用油润滑下涂层的耐磨性比干摩擦下得到显著的提高,摩擦因数从0.12降低到0.08左右;但在高载荷(1100N)下,油润滑对涂层的摩擦磨损性能没有明显的改善。只有在合适的载荷下,固/油复合润滑技术可明显改善摩擦副的润滑性能。     

MoS2/石墨溅射涂层在真空中不同载荷下的摩擦磨损行为研究

为改进纯MoS2涂层的耐磨损性能,采用溅射技术合成了添加石墨的MoS2涂层。在球-盘摩擦试验机上,考察了法向载荷对MoS2/石墨溅射涂层真空中的摩擦因数和磨损率的影响,并利用扫描电子显微镜对其磨损形貌进行了分析。结果表明:在真空条件下,涂层的摩擦因数随着法向载荷的增大而减小;磨损率随载荷的增加而增加。涂层在真空中较低载荷下的磨损机制为疲劳磨损;在较高载荷下的磨损主要由塑性变形引起的小板片磨损控制。     

WC-10Co-4Cr涂层高温微动磨损特性

为研究WC-10Co-4Cr涂层的高温微动磨损性能和微动磨损机制,采用超音速火焰喷涂技术在Inconel690合金表面制备WC-10Co-4Cr涂层。使用PLINT电液伺服高温微动试验机,在室温25℃至高温300℃大气气氛条件下,选择法向载荷100 N、位移幅值200μm、频率2 Hz、循环次数3×10~4次,进行微动磨损特性试验,通过扫描电子显微镜、双模式轮廓仪和三维共聚焦显微镜等仪器对磨痕进行分析研究。结果表明:涂层组织呈层状叠加的两相分布,致密、孔隙率低,涂层与基体结合紧密,显微硬度为HV810.82,是基体的3.3倍;在法向载荷和位移幅值一定时,随着试验温度的升高WC-10Co-4Cr涂层的摩擦因数增大,且磨损加剧;温度高于250℃条件下,WC-10Co-4Cr涂层发生严重磨损;WC-10Co-4Cr涂层的高温微动磨损机制主要表现为黏着磨损、氧化和剥层的共同作用。     

镀银铜材料在大电流条件下的载流微动磨损特性

利用化学电镀方法在T2紫铜管表面镀银制备镀银铜试样,采用自主研制的切向微动磨损试验设备在圆柱/圆柱的正交点接触模式下进行室温载流切向微动磨损试验,探究了镀银铜试样在5 A电流以及不同法向载荷(5,10,15 N)和位移幅值(30,50,70,100μm)下的载流微动磨损行为及其磨损机制。结果表明：随着位移幅值的增加,镀银铜试样的载流微动磨损程度加剧,随着循环次数的增加,不同位移幅值下的摩擦因数整体呈先减小后增大最后趋于稳定的趋势,而接触电阻呈相反趋势,不同位移幅值下稳定阶段的摩擦因数相差不大;随着载荷的增加,载流微动磨损程度先变大后变小,当载荷为10 N时,磨损程度最大,此时有效接触面积较大,接触电阻较低;随着载荷的增加,稳定阶段的摩擦因数增大。镀银铜试样在磨损初期的磨损机制主要黏着磨损和氧化磨损,在磨损后期主要为磨粒磨损、氧化磨损和剥层,且随着循环次数的增加,氧化磨损程度加剧。     

稀土化合物改性复合材料在油润滑下的摩擦学性能

以竹纤维为增强相,通过稀土化合物改性制备一种树脂基复合材料;采用环块式摩擦磨损实验,研究稀土化合物改性复合材料在油润滑状态下载荷、转速对试样摩擦学性能的影响,以及稀土化合物改性对复合材料试样摩擦学性能的影响;比较干摩擦状态和油润滑状态下复合材料的摩擦学性能,观察和分析试样磨损表面形貌,探讨其磨损机制。实验结果表明:油润滑条件下,稀土化合物改性复合材料的摩擦因数和磨损率都随着载荷的增大而增加;较高载荷下摩擦因数随着转速的增大先增加后减小,而磨损率则呈现逐步增加的趋势;稀土化合物的改性使竹纤维和基体界面结合更为紧密,提高摩擦因数的同时降低了磨损率;在油润滑作用下,试样磨损由干摩擦时的磨粒磨损和疲劳磨损转变成为轻微的疲劳磨损;在油润滑状态下,复合材料处于边界润滑状态,故摩擦因数和磨损率均低于干摩擦。     

AZ91D镁合金微动磨损特性研究

采用液压高精度材料试验机考察了平面一球面接触的AZ91D镁合金摩擦副的微动磨损行为，分析了位移幅值、法向载荷和频率等参数对摩擦因数和磨损体积的影响，考察了不同实验条件下的磨斑形貌，并探讨了其磨损机理。结果表明：AZ91D镁合金的微动区域可分为部分滑移区、混合区和滑移区3个区域，粘着磨损、疲劳磨损和磨粒磨损分别是3个区域的主要磨损机制；磨损体积随着位移幅值和法向载荷的增加而增大，但却随着频率的增大而减小。在微动部分滑移区和混合区，摩擦因数随着位移增大迅速增加；在微动滑移区，摩擦因数随法向载荷的增大而减小，而位移幅值和频率对摩擦因数的影响较小。     

Ag膜在干摩擦、油和脂润滑下的摩擦学性能研究

精密运转部件表面沉积一层软金属银和银基固体薄膜可以有效地降低摩擦、减小磨损。通过钢球/镀Ag膜摩擦盘在干摩擦、4122油和L252脂润滑条件下的球-盘摩擦学试验,研究Ag膜在油和脂复合润滑下的摩擦学性能,分析润滑条件、载荷、速度对Ag膜摩擦因数的影响。试验结果表明:在4 N法向载荷和油、脂润滑下,与干摩擦相比,镀Ag膜摩擦副的最大静摩擦因数分别减小了10.7%和6.1%;在0～2 000 r/min转速范围内,Ag膜摩擦因数随转速增加而减小,与干摩擦相比,油润滑下Ag膜摩擦因数减小9%～48%,脂润滑下Ag膜摩擦因数减小17%～52%。Ag膜在干摩擦、4122润滑油和L252润滑脂复合润滑下,摩擦因数均随载荷增加而降低;Ag膜摩擦副/钢球在油、脂复合润滑下启动摩擦力矩小,摩擦副在宽转速范围内摩擦因数变化小,运转平稳。     

永磁场条件下45钢与GCr15钢摩擦磨损性能试验研究

基于HSR-2M高速往复摩擦磨损试验机,研究在永磁体磁场条件下滑动速度、载荷等参数对45#钢/GCr15钢摩擦副摩擦学性能的影响,通过磨痕形貌分析其磨损机制,并与无磁场条件下的试验结果进行对比。试验结果表明:磁场的引入可以在一定程度上减小摩擦因数和降低磨损率,证明磁场能够改善45#钢/GCr15钢摩擦副的摩擦学性能;增大滑动速度将降低摩擦因数和磨损率,增大载荷将降低摩擦因数,增加磨损率。无磁场时,摩擦副的摩擦磨损为典型的磨粒磨损,磨损系统的磨损率和摩擦因数较大;有磁场时,磨损形式主要为黏着磨损,摩擦因数和磨损率较小。     

粘结MoS2固体润滑涂层的转动微动磨损特性

采用粘结法在LZ50钢表面制备MoS2固体润滑涂层,研究MoS2涂层及LZ50钢基体在干态不同角位移幅值下的转动微动磨损行为。在分析转动微动动力学特性的同时,结合光学显微镜、扫描电子显微镜、电子能谱仪以及轮廓仪对磨痕形貌进行微观分析。结果表明:涂层和基体的转动微动运行区域仅呈现部分滑移区(Partial slip regime,PSR)和滑移区(Slip regime,SR),未观察到混合区。涂层改变基体的微动运行区域,使得PSR缩小,SR运行区域向小角位移幅值方向移动。由于MoS2涂层的固体润滑作用,涂层的摩擦因数在整个试验过程都明显低于基体。在PSR,涂层损伤轻微;在SR,涂层的转动微动磨损机制主要表现为剥层和摩擦氧化。研究表明粘结MoS2固体润滑涂层具有明显的防护作用,显著降低LZ50钢的转动微动磨损。     

Reciprocating Sliding Wear Performance of Hard Coating on Modified Titanium Alloy Surfaces

The high strength, low weight, and outstanding corrosion resistance properties possessed by titanium alloys have led to a wide range of successful applications in aerospace, automotive, and chemical industries and in power generation. Titanium alloys are characterized by poor wear resistance properties and their utilization has been excessive in nontribological applications. Surface texturing is a well-known and effective means of surface modification to improve the tribological properties of sliding surfaces. In the present work, modification of titanium alloy surfaces (Ti6Al4V) was done by lapping and laser surface texturing. The wear-resistant coating, AlCrN, was applied over the modified titanium alloy surfaces, with and without a chromium interlayer. Linear reciprocating sliding wear tests were performed with ball-on-flat contact geometry to evaluate the tribological performance of the coated alloy. The tests were performed under different normal loads for a period of 105 cycles at a frequency of 5 Hz. The friction force between the contact pair and displacement of the ball were simultaneously observed using a force transducer and laser displacement sensor. Optical microscopy was used to quantify the wear volume by measuring the wear scar diameter on both the specimen and the counterbody. Scanning electron microscopy (SEM) was employed to study the morphology of the wear scar. The characteristic behavior of the AlCrN coating such as bonding strength, wear volume, wear rate, and coefficient of friction with the chromium interlayer was evaluated and compared with the coating directly applied over the substrate. The coating on the textured surface, with the chromium interlayer showed better tribological performance.     

Tribological Behavior of Composites Based on ZA-27 Alloy Reinforced with Graphite Particles

The objective of this investigation is to assess the influence of graphite reinforcement on tribological behavior of ZA-27 alloy. The composite with 2 wt% of graphite particles was produced by the compocasting procedure. Tribological properties of unreinforced alloy and composite were studied, using block-on-disk tribometer, under dry and lubricated sliding conditions at different specific loads and sliding speeds. The worn surfaces of the samples were examined by the scanning electron microscopy (SEM). The obtained results revealed that ZA-27/graphite composite specimens exhibited significantly lower wear rate and coefficient of friction than the matrix alloy specimens in all the combinations of applied loads (F _n ) and sliding speeds (v) in dry and lubricated tests. The positive tribological effects of graphite reinforcement of ZA-27 in dry sliding tests were provided by the tribo-induced graphite film on the contact surface of composite. In test conditions, characterized by the small graphite content and modest sliding speeds and applied loads, nonuniform tribo-induced graphite films were formed leading to the increase of the friction coefficient and wear rate, with increase of the sliding speed and applied load. In conditions of lubricated sliding, the very fine graphite particles formed in the contact interface mix with the lubricating oil forming the emulsion with improved tribological characteristics. Smeared graphite decreased the negative influence of F _n on tribological response of composites, what is manifested by the mild regime of the boundary lubrication, as well as by realization of the mixed lubrication at lower values of the v/F _n ratio, with respect to the matrix alloy.     

甘油润滑下CrCN涂层的超低摩擦特性

为开发与CrCN涂层具有良好配伍润滑性能的绿色润滑剂,使用磁控溅射技术在304不锈钢表面沉积CrCN涂层,利用场发射扫描电子显微镜、原子力显微镜、纳米压痕仪、维氏硬度计、X射线衍射仪、X射线光电子能谱仪分别对其表面形貌、涂层厚度、力学性能、物相组成以及元素化学价态进行分析,并借助多功能摩擦磨损试验机评价在甘油润滑下CrCN涂层的摩擦学性能,并与PAO6润滑下结果进行比较。利用磁控溅射技术在不锈钢表面构筑的CrCN涂层表面光滑致密,粗糙度仅为1.01 nm,硬度可达14.39 GPa。对比钢-钢和钢-CrCN体系的摩擦学性能发现,钢-CrCN体系在甘油润滑下展现出优异的润滑性能;当负载为0.5 N时,钢-CrCN体系在甘油润滑下的摩擦因数可低至0.01,大大低于PAO6润滑下的摩擦因数。对磨痕的XPS分析表明,在摩擦过程中,甘油发生摩擦化学反应,在CrCN涂层的接触表面生成一层FeOOH层,甘油分子及其降解产物可能进一步吸附在FeOOH层,形成流体润滑层,有效降低了摩擦和磨损。     

The Effect of Different Temperatures on Friction and Wear Properties of CFRPEEK against AISI 431 Steel under Water Lubrication

The tribological behavior of 30 vol% carbon fiber–reinforced polyetheretherketone (CFRPEEK) against AISI 431 steel under different temperatures of water lubrication was investigated. Friction and wear tests were carried out on a disc-on-disc contact test apparatus under different operating conditions. The results reveal that the lubricant temperature has a significant effect on the friction and wear properties of CFRPEEK sliding against AISI 431 steel. The average friction coefficient and wear rate of CFRPEEK increase with increasing lubricant temperature. However, the wear rate of AISI 431 steel did not have a positive correlation with the wear rate of CFRPEEK under different temperatures of water lubrication. Moreover, the original and worn surfaces of CFRPEEK and AISI 431 steel were imaged by environmental scanning electron microscopy and optical microscopy, respectively. The main tribological mechanisms of CFRPEEK sliding against AISI 431 steel were adhesive wear, and increasing the temperature of the lubricant could accelerate wear.     

Lubrication Effect of the Paraffin Oil Filled with Functionalized Multiwalled Carbon Nanotubes for Bismaleimide Resin

Multiwalled carbon nanotubes (MWCNTs) were functionalized and were used as additives in paraffin oil to improve its lubrication effect for bismaleimide resin. The tribological behavior of bismaleimide resin lubricated by the paraffin oil filled with the functionalized carbon nanotubes was investigated by friction and wear tester. The wear surface of the resin with steel ball as tribopair was analyzed by means of scanning electron microscopy (SEM). It was found that the addition of this kind of functionalized MWCNTs effectively reduced the friction coefficient. An optimal additive concentration existed in the system and was found to be 0.025 wt%. A lubrication model for the resin and steel ball system was postulated and it was the isolating effect and bearing structure of f-MWCNTs that played a key role in friction and wear reduction.     

SLM成形表面织构对TC4钛合金干摩擦磨损性能的影响

基于一步法思路,采用金属3D打印机基于激光选区熔化（SLM）技术制备表面带有凹坑织构的TC4钛合金试样,采用光学相机、超景深显微镜和扫描电镜观察织构成形情况,利用激光共聚焦位移测试仪和显微维氏硬度计分别测试表面粗糙度和表面硬度,在干摩擦条件下采用摩擦磨损试验仪考察不同载荷下织构密度对TC4钛合金试样摩擦学性能的影响,并使用扫描电镜对摩擦实验前后的表面形貌进行分析。研究结果表明：一步法SLM成形能够在TC4钛合金表面获得成形良好的直径500 μm的织构;随着织构密度的提高,钛合金试样表面粗糙度增大,表面硬度有所降低;干摩擦条件下,提高TC4钛合金试样织构密度有利于磨屑的收集从而减少试样的三体磨损,提高载荷有利于改善摩擦副接触状态;5 N载荷下40%织构密度试样的平均摩擦因数和磨痕宽度均最小,与无织构试样相比,平均摩擦因数和磨痕宽度分别降低12%和16%;40%织构密度下,载荷提高会引起摩擦因数的降低和磨损量增大,磨损表面犁沟和片状剥落增多。在干摩擦条件下,3D打印一步法制备的表面织构可以显著改善TC4钛合金的磨粒磨损和黏着磨损。     

用UMT摩擦试验机评价可转位涂层刀片的摩擦学性能

涂层刀具的摩擦学性能评价对于优化涂层技术、确定产品质量、合理编制加工工艺等,都具有重要意义。提出用UMT摩擦试验机来评价刀片涂层的摩擦学性能。以广泛使用的可转位涂层刀片为对象,采用UMT摩擦试验机,结合白光共焦三维表面分析和扫描电子显微镜分析,评价多种涂层刀片的摩擦因数变化规律和磨损性能。结果表明,采用UMT-2磨损试验机,选择适当的试验参数,能有效地评价硬质合金刀具涂层的摩擦学性能。     

聚四氟乙烯基粘结固体润滑涂层微动磨损性能研究

在不同位移幅值与载荷条件下研究了酚醛环氧粘结聚四氟乙烯(PTFE)基固体润滑涂层的微动磨损特性，并利用扫描电子显微镜、表面轮廓仪和傅里叶表面红外仪等对涂层磨斑进行分析。结果表明，粘结PTFE基涂层具有良好的抗微动损伤性能，随循环次数的变化只存在部分滑移区和滑移区，部分滑移区的损伤轻微，滑移区的损伤强烈依赖于栽荷，其损伤与PTFE分子链在往复交变载荷作用下的疲劳断裂相关。