活塞环表面织构化镀层的摩擦性能研究

目的以缸套/活塞环为试验对象,研究激光织构化与固体润滑镀层的协同减摩作用。方法采用脉冲激光在活塞环表面进行微孔化处理,利用电脉冲沉积法在微孔内制备具有不同MoS_2微粒浓度的Ni-MoS_2复合镀层,通过往复式摩擦试验研究织构化表面沉积固体润滑剂对活塞环-缸套的影响机制。结果镀液中MoS_2微粒浓度对镀层的硬度和摩擦学性能影响较大,相同电流密度下,电镀液中MoS_2微粒的质量浓度为5g/L时的镀层硬度最高,该浓度下Ni-MoS_2复合镀层在干摩擦下具有最佳的摩擦系数和最低的磨损率。织构化复合镀层可以显著改善接触面间的摩擦性能,相比未织构化摩擦配副,摩擦系数降低约0.2,磨损率下降50%。结论干摩擦条件下,表面织构可以有效地储存摩擦副之间的固体润滑剂和磨粒,在接触表面形成连续润滑膜,减少磨粒磨损。     

微坑分布位置对复合润滑结构缸套摩擦磨损性能的影响规律

采用电火花加工方法在FeNi合金镀铁缸套试样表面的止点、中点、全程位置刻蚀微坑织构,采用球磨法对微坑填充固体润滑剂MoS_2以制备复合润滑结构缸套。采用对置往复式摩擦磨损试验机,研究微坑分布位置对复合润滑结构缸套摩擦磨损性能的影响规律。采用SEM和EDS研究配副的磨损形貌。结果表明:复合润滑结构缸套能提高承载性能、降低摩擦因数,但不一定都能提高缸套的磨损性能和抗拉缸性能。唯有微坑分布在止点的复合润滑结构缸套相比未处理缸套,表现出良好的减摩耐磨和抗拉缸性能,摩擦因数降低了4.97%~6.26%,对磨环磨损量减少了58.3%,拉缸时间延长了10倍。随着往复运动的进行,微坑中的MoS_2逐渐向缸套表面转移,改善了止点区域的润滑性能,良好保护了摩擦界面。     

Sliding wear characteristics of solid lubricant coating on titanium alloy surface modified by laser texturing and ternary hard coatings

Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because of its severe adhesive wear tendency. The surface modifications through texturing and surface coating were used to enhance the surface properties of the titanium alloy substrate. Hard and wear resistant coatings such as TiAlN and AlCrN were applied over textured titanium alloy surfaces with chromium as interlayer. To improve the friction and wear resisting performance of hard coatings further, solid lubricant, molybdenum disulphide (MoS2), was deposited on dimples made over hard coatings. Unidirectional sliding wear tests were performed with pin on disc contact geometry, to evaluate the tribological performance of coated substrates. The tests were performed under three different normal loads for a period of 40 min at sliding velocity of 2 m/s. The tribological behaviours of multi-layer coatings such as coating structure, friction coefficient and specific wear rate were investigated and analyzed. The lower friction coefficient of approximately 0.1 was found at the early sliding stage, which reduces the material transfer and increases the wear life. Although, the friction coefficient increased to high values after MoS₂ coating was partially removed, substrate was still protected against wear by underlying hard composite layer.     

A comparative study of Cr−X−N (X=Zr, Si) coatings for the improvement of the low-speed torque efficiency of a hydraulic piston pump

The internal parts of hydraulic pumps operating at variable speed should be protected from insufficient lubrication. The axial piston type pumps employ a steel-base cylinder barrel rotating on a soft bronze valves plate with a slide contact, where the insufficient lubrication of these components can cause rapid wear of the valve plate and increase the friction loss. In this study, the cylinder barrel surface was deposited with CrZrN coatings, which were expected to improve the tribological contact with a valve plate under low-speed mixed lubrication conditions. Its effect on the improvement of the low-speed torque efficiency of a hydraulic piston pump was investigated and compared with that from the CrSiN coating. The coated cylinder barrels showed much lower friction coefficients and wear rates of the valve plates than the uncoated plasma-nitride one. In particular, the CrZrN coatings revealed better performance than the CrSiN coatings. By representing the improvement in the torque efficiency of the whole pump based upon the degree of the friction coefficient reduction, the CrZrN coatings exhibited approximately a 0.35% higher improvement at 300 bar and 100 rpm than CrSiN coatings. The possible failure modes of the coatings coated on the barrel were sugested and the microstructures of the coatings seemed to have a strong effect on the film failure mode.     

超音速等离子喷涂Mo涂层的载流摩擦磨损性能

采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备Mo涂层，利用场发射扫描显微镜（SEM）、X射线能谱分析仪（EDS）观测涂层显微形貌与组织成分，分析了载流摩擦中的电接触模型及电弧成因，利用滑动式摩擦试验机研究了电流强度对涂层粗糙度、表面温升及摩擦磨损性能的影响。结果表明：制备的Mo涂层组织致密、氧化程度低，与基体结合方式为“机械铆合”；随电流增加，摩擦副间电弧能量急剧升高，起弧率与表面粗糙度先降低，后上升。其中收缩电阻和微电容产生的自感电动势促进了电弧形成；摩擦副表面的温升由摩擦热、焦耳热、电弧热共同决定，与电流强度呈正相关；摩擦因数受表面粗糙度、材料剪切强度、表面膜等因素共同影响，随电流增加呈下降趋势。此外，载流条件下会出现黏着磨损、氧化磨损、电弧烧蚀等磨损，加剧了涂层剥落与磨粒磨损，但形成的摩擦膜可以有效保护涂层，降低磨损率。     

缸套-活塞环织构化耦合机理及减摩性能研究

目的在工况恶劣的船舶柴油机中,运用表面织构技术提高缸套-活塞环的表面摩擦性能。方法选用实船上的两种缸套-活塞环材料M与W,加工成销盘样式,利用激光打标机在活塞环销上加工圆形凹坑织构,在缸套盘上加工沟槽织构。将未织构化缸套和活塞环与织构化缸套和活塞环互相配对,在RTEC多功能摩擦磨损试验机上进行摩擦磨损试验。从摩擦系数、磨损量、磨损形貌、能谱等方面,进行光滑、单一织构与耦合织构减摩性能的对比分析。结果相比于未织构与单一织构化表面,两种材料的耦合织构均拥有最低的摩擦系数,其中M材料的减摩性能最高增强21.52%,W材料最高增强27.29%。耦合织构还拥有最低的磨损量,使M、W材料的抗磨损能力分别提高81.10%、36.14%。耦合织构能显著降低M、W材料磨损后的表面粗糙度,并提升其润滑油滞留能力。织构内部与接触面的Fe、C分布呈现区域性,在缸套表面磨痕处发现少量Cu元素。结论沟槽与凹坑织构的耦合作用能有效增强油膜的形成与稳定能力,沟槽与凹坑织构可储存磨屑,提升磨屑捕集效率,防止磨屑持续划伤表面。缸套材料中的Cu与耦合织构协同作用,吸附在表面磨痕处,形成软膜,提高承载能力,降低磨损与粗糙度。     

等离子喷涂NiCrAlY-Cu涂层中Cu在宽温域环境下的扩散及摩擦耗散机制

含软金属自适应涂层在摩擦过程因软金属独特的性能而具备良好的摩擦学性能,然而在不断摩擦过程中软金属会发生一定的耗散导致涂层失效。为了研究软金属润滑剂在宽温域摩擦过程中的耗散机制,利用等离子喷涂技术制备NiCrAlY-Cu涂层;通过分析热处理及宽温域摩擦前后涂层的组分与形貌演变,揭示NiCrAlY-Cu涂层中Cu的高温扩散及宽温域摩擦耗散机制。结果表明：Cu以片层状分布在NiCrAlY基础相中,软金属Cu在温度单因素影响下垂直向涂层表面扩散,随着温度的升高扩散加剧。在1000℃环境下Cu在涂层内部发生平行扩散,并最终呈现弥散态分布。在中低温环境下随着温度的升高Cu的剪切强度降低进而使得涂层摩擦因数逐渐下降,但是由于Cu呈片层状分布,随着温度的升高涂层发生疲劳剥落导致磨损率升高。随着温度的进一步升高,Cu扩散加剧,片层状Cu减少,同时发生氧化,使得摩擦因数升高,磨损率降低。在宽温域摩擦过程中由于温度和载荷的共同影响,Cu在涂层中的摩擦耗散机制为Cu垂直向涂层表面扩散,由磨痕区域内向磨痕外平行扩散。同时,磨痕内聚集的Cu以磨屑形式逐渐损耗。提出在不同温域摩擦过程中受力-热耦合影响的软金属耗散机...     

缸套内表面网纹对活塞环润滑性能影响研究

以流体润滑为基础,结合Reynolds方程和微凸体模型在考虑润滑油变黏度等因素条件下,建立活塞环-气缸套三维瞬态流体动压润滑模型。采用有限差分法结合MATLAB语言环境编制瞬态流体动压润滑程序并进行仿真计算,研究缸套内表面网纹对活塞环-缸套润滑摩擦性能的影响。结果表明：采用较大综合粗糙度或者交叉型网纹的缸套时,最小油膜厚度值增大、流体摩擦力和摩擦热流量减小,这对于提高润滑性能、减小活塞环与缸套间的摩擦损失有着重要的作用     

硬质薄膜与自润滑织物衬垫对磨的摩擦磨损性能研究

目的 提高钛合金与自润滑织物衬垫对磨的耐磨性.方法 采用多弧离子镀在TC4钛合金表面制备TiN和CrAlN硬质薄膜,利用扫描电镜、X射线衍射仪、纳米压痕仪、销-盘摩擦磨损试验机、白光干涉扫描轮廓仪测试分析薄膜的形貌、结构、硬度、弹性模量、摩擦磨损性能和磨痕形貌.结果 在相同的测试条件下,TC4钛合金与自润滑织物衬垫对磨时,能更快地进入稳定摩擦阶段,且平均摩擦系数最低,仅为0.12;TiN薄膜进入稳定摩擦阶段所用时间和摩擦系数较TC4钛合金稍有增加;而CrAlN薄膜进入稳定摩擦阶段的用时最长且平均摩擦系数最大.测量摩擦磨损后自润滑织物衬垫磨痕的二维轮廓发现,当与CrAlN薄膜对磨时,自润滑织物衬垫的磨痕深度最大,但磨损率最低,这主要是软质织物衬垫的不均匀磨损引起的.进一步分析发现,所有的试验销表面均形成了转移膜,但CrAlN薄膜表面形成的转移膜最薄,从而导致其摩擦系数最大,磨损率最低.深入分析自润滑织物衬垫磨痕形貌发现,与TC4钛合金对磨的自润滑织物衬垫的磨痕表现为磨粒磨损和纤维束的破损;与TiN薄膜对磨的自润滑织物衬垫的磨痕表现为区域损失和表面不规则的凹痕;与CrAlN薄膜对磨的自润滑织物衬垫的磨痕中纤维束破损严重.结论 与自润滑织物衬垫对磨后,钛合金以及硬质薄膜表面均形成转移膜,CrAlN薄膜表面转移膜最薄,与之对磨的自润滑织物衬垫的磨损率最低.     

Feasibility Study of Using DLC Coating in Conjunction with Laser Ablation process to Improve the Tribological Performance of an Engineering Surface

Increasing demands such as low friction,low wear rate,and long life-time have reached the limits of single DLC coatings.In order to meet the requirements,we propose to use an integrated approach to improve the wear property of an engineering surface.Firstly,dimples are introduced perpendicular to an engineering surface by a Nd:YAG laser emitting at 1064 nm.Subsequently,solid lubricant DLC is prepared on the patterned surface by magnetron sputtering technique.The effect of dimple densities from 7%to 45 %on tribological properties of the coating surface was revealed.The wear performance of the textured DLC surfaces was studied by a pin-on-disk reciprocating sliding wear tester under boundary lubrication and dry conditions.The results showed that the DLC coatings with appropriate dimple densities have an obvious improvement on wear performance in term of friction coefficient,wear rate and wear life,as compared to un-textured DLC coatings.In boundary lubrication conditions,the improved wear performance can be explained by the promotion of reservoirs to enhance lubricant retention during sliding.In dry condition,the dimples trap wear particles and leave a free interface between pin and sliding contact surface,and avoid the surface worn by abrasive manner,thereby improving the wear performance of the DLC coating.     

Bio-mimetic surface structuring of coating for tribological applications

A novel multilayered coating was developed for applications associated with friction reduction and wear resistance improvement. The nano-engineered coating integrates a soft lubricating layer, consisting of MoS₂-PTFE, onto hard load-supporting layers, with controlled surface morphology (roughness and patterning) of cBN-TiN. The coating was synthesized by sequential procedures including electrostatic spray deposition of cBN particles with different average particle sizes, chemical vapor deposition of TiN, deposition of nano- and micro-sized MoS₂ dispersed in PTFE, and curing. The effect of cBN particle size (with different combinations of particle size) and deposition parameters (specifically electrical voltage) on the cBN-TiN surface morphology were studied experimentally and optimized. SEM characterization of the as-synthesized cBN-TiN coating shows surface features similar to that of colocasia esculenta, with alternating nano- and micro-sized domes and “pockets”; the MoS₂-PTFE top layer has MoS₂ particles retained in the pockets by a basket structure formed during PTFE curing. Tribological and scratch tests were carried out for the as-prepared cBN-TiN and cBN-TiN/MoS₂-PTFE multilayered coatings. Sliding test results demonstrate significantly lower friction coefficient for the multilayered coating, showing that the unique integration of soft lubricating layer and biomimetically structured hard layer can effectively improve tribological performance. It is suggested that lubrication at the frictional contacts was realized by continuous release of the lubricants, MoS₂ and PTFE, from the pockets.     

大变形纯钛微弧氧化膜层的生物摩擦学性能研究

采用微弧氧化法在纯钛及大变形纯钛表面制备多孔氧化膜层,研究微弧氧化膜层在干摩擦、模拟体液和小牛血清不同润滑介质条件下的生物摩擦学性能,探讨钛基材组织细化对其膜层表面摩擦磨损性能的影响。结果表明：与纯钛微弧氧化膜层相比,大变形纯钛微弧氧化膜层耐磨性能更优的原因在于钛基材晶粒的细化使得晶体缺陷增多,为微弧氧化膜层的形核提供了更多的能量,反应生成的TiO2膜层硬度更强,膜层表面更致密均匀光滑,提高了其摩擦磨损性能所致。大变形纯钛微弧氧化膜层在小牛血清润滑时的摩擦系数和磨损程度都优于干摩擦和模拟体液润滑条件下的摩擦系数与磨损情况。这归因于小牛血清于摩擦表面形成的化学反应膜及物理吸附膜,起到了更有效的润滑、冷却与承载作用。     

激光表面织构微坑形貌及面积占有率对氮化气缸套摩擦学性能的影响

针对氮化气缸套由于自身存在表面应力高、易变形等使其难以满足高强化内燃机气缸套要求的问题,以氮化气缸套-PVD活塞环为研究对象,采用Nd-YAG脉冲激光器在氮化气缸套表面进行织构化处理,研究脉冲激光参数对气缸套表面微织构微坑形貌及面积占有率对摩擦副摩擦磨损性能的影响,并分析其影响机制。发现织构微坑直径随激光能量密度、脉冲次数、离焦量增加而增大,而微坑深度随能量密度、脉冲个数、离焦量的增加呈先增大后减小的趋势。不同面积占有率织构对气缸套-活塞环摩擦副均具有减摩耐磨作用,与无织构缸套摩擦副相比,微织构气缸套的摩擦因数降低10.07%～1.58%;磨损量降低26.71%～46.19%;微织构气缸套对应的活塞环试样磨损量降低10.12%～50.19%;微织构气缸套的拉缸时间提高了2.1～2.8倍。最低摩擦因数和磨损量及最佳抗拉缸性能均在面积占有率为10%的织构摩擦副获得。微织构改善气缸套摩擦副摩擦磨损性能的机制为贮存润滑油,减少摩擦副接触面积以及捕捉磨屑,减小磨粒磨损。获得了高强化条件下氮化气缸套织构化对其摩擦学性能的影响规律,可为开发高强度内燃机提供试验支持。     

活塞-缸套表面纹理摩擦磨损特性研究进展

减少摩擦损失是高性能发动机效率的一个重要方面。活塞作为发动机组成的一个重要部件,在机械损失上损耗了发动机产生的总能量的40%,近乎于占据了发动机摩擦损失能量的一半,因此在发动机活塞-缸套上制备表面织构以改善活塞摩擦副的摩擦学性能,保持发动机在实际运行中拥有良好的性能是现在发动机发展不可或缺的。表面纹理已广泛应用于改善滑动表面的摩擦性能,减少磨损、减低摩擦等是表面纹理化应用在减摩抗磨方面最直接的效果体现。主要围绕近些年发表关于表面织构几何参数对活塞-缸套的影响,从有限元模拟分析以及实验室试验研究等两个方面综述织构应用在活塞-缸套上的研究进展,再从织构形状、织构面密度、织构排列方式及其他参数方面等方面对活塞/缸套的摩擦磨损影响进行对比分析,以帮助后续研究者在该方向的研究提供参考。依据机械部件之间的磨损量以及摩擦因数体现出表面织构运用之后的摩擦学性能。最后对表面织构在活塞-缸套上的发展趋势进行展望。     

等离子喷涂制备WC-Co-Cu-BaF2/CaF2自润滑耐磨涂层及其高温摩擦性能

通过大气等离子喷涂方法,使用自制的含有WC-Co、Cu和BaF2/CaF2共晶体的复合喷涂粉末,制备出WC-Co-Cu-BaF2/CaF2自润滑耐磨涂层。在200℃、400℃和600℃下进行WC-Co-Cu-BaF2/CaF2涂层和WC-Co涂层的高温摩擦试验,用扫描电镜观察涂层磨损表面微观形貌。结果表明:200℃时,由于WC-Co-Cu-BaF2/CaF2涂层摩擦产物层中含有的WC硬质颗粒引起磨粒磨损,该涂层摩擦因数和磨损率相对较高。而400℃和600℃时,WC-Co-Cu-BaF2/CaF2涂层的摩擦产物层中均无WC颗粒存在,且由于涂层中Cu和BaF2/CaF2等固体润滑剂的作用,生成的摩擦产物层光滑且致密,涂层的摩擦因数和磨损率均较低,在400～600℃下表现出比WC-Co涂层优异的耐磨性能。     

温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响

采用超音速火焰喷涂(HVOF)制备了WC-WB-CoCr涂层,研究了温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响。通过SEM、XRD和显微硬度仪对涂层的微观组织、相结构和力学性能进行表征。通过摩擦磨损试验机和拉曼光谱仪研究了WC-WB-CoCr涂层的高温摩擦学性能和氧化产物,采用台阶仪扫描磨痕形貌并计算WC-WB-CoCr涂层的磨损率。结果表明：WC-WB-Co-Cr涂层主要由WC和CoW₂B₂组成,涂层结构致密,与基体结合紧密;随着磨损试验温度升高,涂层的摩擦系数从0.66降低到0.57,涂层的磨损率随着温度的升高而升高,但是其磨损率增长程度随着温度的升高而降低。在高温磨损过程中,磨痕表面的氧化膜主要由WO₃和CoWO₄组成,且CoWO₄比WO₃表现出更好的耐高温磨损性能。涂层的主要磨损机制为氧化磨损、疲劳磨损和粘着磨损。     

润滑条件下WC-CoCr涂层的磨损行为

研究了在润滑条件下,WC-CoCr涂层与SiC摩擦副对磨时的摩擦和磨损性能,分析了加载载荷和润滑条件(干摩擦、润滑脂、金刚石研磨膏)对WC-CoCr涂层摩擦系数和磨损量的影响规律,对涂层的磨损机理进行了探讨。实验结果表明:脂润滑时,WC-CoCr涂层与SiC摩擦副对磨时的摩擦系数和磨损率降为最小,其中摩擦系数基本在0.1左右波动;金刚石研磨膏润滑时,磨损率高达1.521 24×10-6 g/m,为干摩擦条件下的2.68倍,抗磨减摩效果不理想;干摩擦时,涂层表面存在硬挤压痕,主要磨损机制为微切削并伴随着塑性变形,而在金刚石研磨膏润滑条件下,三体磨粒磨损起主导作用。     

多弧离子镀制备TiSiN-Cu涂层的结构和摩擦学性能

目的通过在TiSiN涂层中掺杂软金属Cu,提高TiSiN涂层的摩擦性能。方法采用多弧离子镀技术,在316L不锈钢基体上沉积TiSiN-Cu涂层。用扫描电子显微镜(SEM)观察涂层的表面形貌,用X射线光电子能谱仪(XPS)和X射线衍射仪(XRD)来分析涂层的元素组成和相组成,通过纳米压痕硬度测试和摩擦磨损实验,表征不同Cu含量TiSiN-Cu涂层的力学性能和摩擦学性能。结果 Cu含量对TiSiN涂层的结构、硬度和摩擦性能有明显影响。Cu在涂层中主要以单质形式存在,由于与空气接触,涂层表面有少量的CuO。随着Cu含量的增加,TiN的晶粒尺寸先减小后增加,硬度先升高后降低。在Cu原子数分数为6.28%时,硬度达到最大值29.26 GPa。在干摩擦条件下,TiSiN-Cu涂层的磨损率在Cu原子数分数为12.93%时达到最低,为6.65×10-7 mm~3/(N·m)。在海水环境下,涂层的磨损率较大。结论软金属Cu作为固体润滑颗粒可以明显改善Ti Si N涂层的干摩擦性能,在海水条件下,摩擦与腐蚀的交互作用加速了涂层材料的损耗。     

等离子喷涂典型耐磨涂层材料体系与性能现状研究

等离子喷涂作为重要的热喷涂技术之一,在零件表面强化处理与再制造损伤修复领域具有广泛的应用.由于不同机械零部件工作环境(温度、转速、腐蚀环境、润滑状况等)、基体材质及运动形式等因素存在较大的差异,因而通常需根据其具体服役工况选择最优的表面强化涂层,以满足零件表面摩擦学性能需求,提升机械装备的综合服役性能.基于此,对国内外...     

低黏度0W-16汽油机油减摩性能研究

目的 研究低黏度0W-16机油的减摩性能。方法 选取3种减摩剂MoDTC、GMO和油酸酰胺,分别按一定比例加入到0W-16基础油中,获得单剂油样,并选取2种0W-16全配方机油（A-1油和A-2油）,利用SRV-IV试验机测试润滑油样的减摩性能和极压性能,利用傅立叶红外光谱仪和油料元素光谱分析仪分析机油油样结构,并利用3D光学表面轮廓仪表征缸套块磨痕形貌。结果 对于单剂油样,0W-16基础油分别加入MoDTC、GMO和油酸酰胺后,平均摩擦系数由0.198分别减小到0.088~0.116、0.167~0.178和0.179~0.194,缸套块磨痕平均深度由3.59 mm分别减小到0.44~0.52 mm、2.11~2.24 mm和3.19~3.44 mm。对于0W-16全配方机油,在摩擦润滑试验低温区,A-1油比A-2油摩擦系数低,随着温度升高,A-1油和A-2油的摩擦系数进一步减小;摩擦润滑试验后,A-1油和A-2油的缸套块磨痕平均深度分别为0.13 mm和0.18 mm。在极压试验中,A-1油和A-2油的极压值分别为1500 N和900 N。结论 在0W-16基础油中分别加入3种减摩剂后,MoDTC的减摩和抗磨作用最好,油酸酰胺的减摩和抗磨作用最差。对于0W-16全配方机油,在摩擦润滑试验低温区,A-1油中的无灰减摩剂和MoDTC产生协同作用,表现出更低的摩擦系数;随着温度升高,A-1油和A-2油中的ZDDP与MoDTC产生协同作用,进一步降低摩擦系数。在极压试验中,A-1油中的ZDDP与其他添加剂产生协同作用,表现出更大的极压值。添加剂之间的协同作用对油品节能性能产生重要影响。