钛合金表面Ni-P-PTFE自润滑复合镀层的制备及其摩擦磨损性能

为提高钛合金零部件的使用寿命,以传统的化学镀Ni-P合金工艺为基础,通过添加PTFE粒子使其均匀分布在Ni-P合金镀层中,在钛合金基体上制备了具有耐磨、减摩性能的自润滑复合镀层;分析了PTFE乳液浓度、表面活性剂浓度等参数对复合镀层中PTFE微粒子含量的影响规律;采用SEM、EDS和XRD等手段对复合镀层的微观形貌、相结构和成分进行了分析;研究了不同PTFE含量复合镀层及钛合金基体在相同载荷下的摩擦磨损性能。结果表明:Ni-P-PTFE复合镀层具有良好的减摩耐磨性能,当膜层中PTFE微粒子的含量为20.4%(体积分数)时,钛合金表面的摩擦系数降至0.2左右,而磨损量也显著减小。     

纳米SiO2对聚丙烯酸酯复合涂层在水润滑下摩擦学性能的影响

考察了纳米SiO₂对聚丙烯酸酯复合涂层在水润滑下摩擦磨损性能的影响。利用FTIR分析纳米SiO₂与聚丙烯酸酯的界面结合;利用SEM观察复合涂层磨损表面,并结合FTIR和摩擦磨损实验分析其磨损机理。结果表明:水润滑时,聚丙烯酸酯在摩擦过程中会发生摩擦化学反应,引起涂层摩擦腐蚀磨损;而纳米SiO₂能与聚丙烯酸酯以化学键的形式结合,它的加入有助于摩擦界面在水介质中形成具有较好减摩作用的表面膜和水分子膜,提高聚丙烯酸酯复合涂层的耐磨性。在水润滑下,当纳米SiO₂的含量较低时,涂层表面的磨损形式为摩擦腐蚀磨损和磨粒磨损;当纳米SiO₂的含量达到5wt% 时,涂层表面形成完整的表面膜和水分子膜,此时涂层具有良好的摩擦学性能。      

Diamond-like carbon coatings for orthopaedic applications: an evaluation of tribological performance

A detailed investigation of the tribological behaviour of vacuum arc diamond-like carbon coated Ti–6Al–4V against a medical grade ultra-high molecular weight polyethylene is conducted in this work in order to investigate the potential use of diamond-like carbon coatings for orthopaedic appplications. Lubricated and non-lubricated wear experiments are performed using a standard pin-on-disc wear tester. The coefficient of friction is monitored continuously during testing and wear rate calculations are performed using surface profilometry measurements of worn disc surfaces. Sliding wear tests show the existence of two distinct friction and wear regimes distinguished by physically different mechanisms. In the first stages of wear, adhesion and abrasion are the dominant mechanisms of wear while fatigue processes are activated later in the tests. The effects of diamond-like carbon coating structure, surface roughness and lubrication on tribological behaviour are presented. Optimal process–structure–property design for vacuum arc plasma deposition is utilized in order to obtain strong adhesion to the titanium alloy substrate. Diamond-like carbon coatings significantly improve the friction and wear performance of the orthopaedic bearing pair and show exceptional promise for biomedical applications. © 1999 Kluwer Academic Publishers     

含硫镍基合金与YJ2硬质合金对偶的高温摩擦特征分析

本文研究了通过热压法制备得到的含硫镍基合金与YJ2硬质合金对偶的摩擦特征。结果表明：在高温摩擦过程中，材料中的硫化物共晶体是主要的润滑组元，摩擦面的温度对其润滑效果有较大的影响；材料与YJ2对偶时的摩擦系数随着温度变化有所不同，但是磨损率都随着温度升高而增大，其高温下磨损形式主要为磨粒磨损和氧化磨损；YJ2硬质合金表面生成的氧化物对材料减摩性能有很大影响。     

The Effect of Hard Coating Properties on Substrate Stresses Under Tribological Loads

A study has been carried out using finite element methods to investigate the influence of hard coatings on substrate stresses under tribological and thermal loads. The study was performed under a uniform distribution of traction (normal and tangential pressure) and temperature. The stresses have been calculated in terms of the ratio of the modulus of elasticity between coating and substrate and the ratio of the coating thickness to the loading strip length at different coefficients of friction and temperatures. The heat transfer problem was solved with regard to a variety of coating properties and the output temperature applied as a thermal load in the structure problem. It is shown that altering the coating modulus of elasticity and coefficient of friction in the presence of a temperature change affects the maximum equivalent stress in the substrate and changes its location. The simulations carried out are discussed in terms of the potential benefits of plasma-based surface coatings and treatments in improving tool performance and the requirements for coating design specifications which will allow design engineers to build surface treatments into new tool designs.     

氮离子注入浓度对弹条钢基体Cr/CrSiN复合涂层的摩擦学性能影响研究

在轨道用扣件弹条钢(60Si2Cr)上注入不同浓度的氮离子,用电弧离子镀技术沉积了Cr过渡层,并在其上制备了CrSiN/Cr复合涂层。在UMT-3多功能摩擦磨损机上对复合层进行了法向载荷为20N的摩擦磨损实验,探讨了经不同氮离子注入浓度后Cr/CrSiN复合涂层摩擦磨损行为和损伤机理,研究发现,经氮离子注入后,复合涂层表面硬度明显的增加,随着离子注入浓度的升高涂层的耐磨性逐渐提高,其磨损机制主要为剥落和磨粒磨损。     

Tribological property and drilling application of Ti-C:H and Cr-C:H coatings on high-speed steel substrates

This study investigates the tribological properties and cutting performance of Ti-DLC and Cr-DLC doped metal coatings. The tribological properties of the coatings are evaluated by testing coated disks against an AISI 1045 steel counterbody under dry conditions using an oscillating friction wear tester, and then measuring the subsequent wear depth on the coated disk, the wear width on the steel counterbody, and the friction coefficient. The cutting performance of the coatings is evaluated by using coated high-speed drills to machine stainless steel workpieces, and then measuring the resulting flank wear and hole surface roughness. The results of the wear tests show that the Ti-C:H and Ti-C:H/TiC/TiCN/TiN coatings possess excellent tribological properties, including low coefficients of friction, low wear depths, and low wear widths. Regarding the machining tests, the Ti-C:H/TiC/TiCN/TiN coating has the lowest flank wear and yields the highest hole surface quality under both dry and cutting fluid drilling conditions. The single Ti-C:H coating has excellent tribological properties, but demonstrates a relatively poorer performance in the drilling of stainless steel. Finally, the Cr-DLC coatings all exhibit a poor cutting performance under dry cutting conditions.     

Analysis of plastic deformation in diamond like carbon films-steel substrate system with tribological tests

The influence of plastic deformation of the substrate on the tribological properties of diamond like carbon (DLC) films was investigated in DLC films-steel substrate system. The tribological properties of DLC films deposited on different hardness steel were evaluated by a ball on disk rotating-type friction tester at room temperature under different environments. In dry nitrogen, DLC films on soft steel exhibited excellent tribological properties, especially obvious under high load (such as 20 N and 50 N). However, DLC films on hard steel were worn out quickly at load of 20 N. Plastic deformation was observed on soft steel after tribological tests. The width and depth of plastic deformation track increased with increase of the experimental load. Super low friction and no measurable wear were kept in good condition even large plastic deformation under high load conditions in DLC films-soft steel system. In open air, DLC films on soft steel exhibited high coefficient of friction and DLC films on ball were worn out quickly. Plastic deformation was not observed on soft steel because the contact area increased and the thick hardened layer on contact surface were formed by DLC films and debris particles together on the steel substrate. The wear track on steel became deep and wide with increase of loads and DLC films were worn out. The experimental results showed that super low friction and high wear resistance of DLC films on soft steel can be attributed to the good adhesion and plastic deformation. Plastic deformation played an active role in the tribological properties of DLC films on soft steel in the present work.     

Dry sliding wear behaviour at ambient and elevated temperatures of plasma transferred arc deposited aluminium composite coatings

Abstract

Plasma transferred arc (PTA) surfacing is a surface engineering process in which a coating is deposited on the substrate by the injection of metal powders and/or ceramic particles into the weld pool created by the formation of a plasma plume. The present work involved the tribological evaluation of metal matrix composite (MMC) coatings deposited onto an aluminium alloy using the PTA technique. Coatings were fabricated by the deposition of an Al–Ni powder containing either Al₂O₃ or SiC particles. Dry sliding wear behaviour of the coatings was evaluated at ambient and elevated temperatures. Under sliding conditions of low applied stress and ambient temperature, reinforcement properties such as interfacial structure and fracture toughness have a significant influence on wear resistance. The SiC particles, which exhibit high interfacial bonding and toughness, support the matrix by acting as load bearing elements, thereby delaying the transition in wear mechanism as applied stress increases. As applied stresses exceed the fracture strength of the SiC and Al₂O₃ particles, these particles suffer fragmentation and/or debonding and no longer support the matrix. At higher stresses and elevated temperature, matrix properties such as flow stress and the tribolayer formation play more important roles in determining wear resistance.     

TA15合金表面Ni-SiC复合镀层的摩擦磨损性能

采用共沉积法在TA15合金表面制备了Ni-SiC复合镀层, 分析了Ni-SiC复合镀层对基体合金硬度和磨擦磨损性能的影响, 并对其摩擦磨损机制进行了讨论。结果表明: 所制备的Ni-SiC复合镀层组织致密且与基体结合紧密, 硬度明显高于TA15合金基体。摩擦磨损实验结果表明, Ni-SiC复合镀层能为TA15合金提供良好的摩擦磨损抗力, 在相同的摩擦条件下, Ni-SiC复合镀层的磨损率明显低于TA15合金。TA15合金与GCr15球和Al₂O₃球对磨的磨损机制均主要为犁削磨损、粘着磨损, 同时伴随有氧化磨损和轻微的磨粒磨损; Ni-SiC复合镀层与GCr15磨球对磨的磨损机制主要为镀层组织的拔出及GCr15钢球在其表面上的涂抹, 与Al₂O₃磨球对磨时的磨损机制主要为疲劳磨损和削层磨损。     

Einfluss der Mikrostruktur auf das Verschleiß‐ verhalten der hartanodisierten Aluminium‐legierungen EN AW‐6082 und EN AW‐7075

Microstructural effect on the wear behaviour of the hard‐anodised aluminium alloys EN AW‐6082 and EN AW‐7075 The suitability of hard‐anodising of high‐strength Al alloys (EN AW‐7075‐T651) for the fabrication of protective coatings which are also applicable on screws was investigated. A medium‐strength AlSi1MgMn alloy (AA60682‐T6), generally rated as applicable for anodising, was used as reference material. After possible setting phenomena of a screw joint, the load‐bearing surface of the screw can be subjected to an oscillating relative movement. The damaging tribological load was simulated in an oscillation wear test. The resulting wear appearances have revealed that the untreated oxide coatings on the EN AW‐6082 substrate are not capable of providing protection against tribological load. Since hot‐water sealing increases the hardness of the coating but also contains the technology‐induced risk of softening the substrate material, other tribological protection methods have been looked for. The analysis of the tribological tests (characterisation of the structure and the resulting properties of the material, measurement of the wear amount and analysis of the wear appearance) have shown that the films sealed with wax emulsion on both substrate materials are the most promising candidates for the application of devices under oscillation wear. The obtained roughness, friction coefficients and hardness values confirm the positive behaviour of the anodically oxidised EN AW‐7075‐T651 alloy under the chosen tribological load.     

Tribological Properties of Mo-N Hard Coatings on Ti6Al4V by Double Glow Discharge Technique

Mo-N hard coatings on Ti6Al4V were formed using double glow discharge technique. The fundamental coating properties, such as the phase, hardness and elastic modulus were investigated. The tribological performances of the coatings in dry wear condition were studied by means of ball-on-disc wear machine. The experimental results showed that the thickness of the Mo-N hard coating was about 10 µm. The coating was single fcc γ-Mo2N phase with (200) preferred orientation. The hardness and the elastic modulus of the coating was 13.80 GPa and 261.65 GPa respectively. The surface treatment enhanced the hardness and elastic modulus of the surface of Ti6Al4V base greatly. With GCr15 slider ball, the friction coefficient of the Mo-N hard coating was in the range of 0.56~0.65 at the steady state. Though the coating did not show friction reducing effect, it improved the wear resistance of Ti6Al4V greatly.     

Nickel-based wear-resistant coatings by vacuum melting

In various coating processes nickel-based hard alloy powders are applied in either an atomized or a mechanically pulverized form. The coatings show good corrosion resistance, a high abrasion resistance and a relatively low melting point. Since boron is sparingly soluble in nickel, the boride Ni₃B forms a low melting eutectic at about 1000 °C with the nickel solid solution. Boron and silicon act simultaneously as deoxidizers and improve both the properties of the coating and the bonding to the substrate. Diffusion into the substrate occurs during the coating procedures.In this paper we discuss the behaviour of heterogeneous powder compounds with nickel hard alloys. For many applications mixtures with various carbides are used. During coating, reactions take place between the Ni-Cr matrix and the added carbides. These heterogeneous or quasi-alloys, which are used because of their abrasion resistance, are metastable.The abrasion resistance depends primarily on the phases as well as on their grain size, the grain size distribution and alterations to the matrix. When carbidic quasi-alloys are exposed to abrasion and corrosion at high temperatures, reactions of the existing phases during use cannot be completely excluded. Heat treatment causes changes in the structure and abrasion resistance of carbide-containing quasi-alloys.It is difficult to follow reactions which take place during coating either in the fused mass of quasi-alloys or in heterogeneous compounds. Because of their relatively low melting points nickel-based hard alloys can be coated by furnace melting. Hence carbide compounds with Ni-Cr-B-Si powder alloys are most suitable for research also. In these mechanical alloys segregation, of relevance to practical applications, can be studied as well as the formation of various phases during the coating or heat treatment processes.The behaviour of mixtures of Ni-Cr-B-Si powder alloy with different amounts of a number of carbides is reported. The structures of the resulting phases were studied and we tried to correlate these with the results of our abrasion tests.For tungsten carbide-nickel hard alloy mixtures the formation of the ? phase is influenced by the coating parameters and the matrix as well as by the diffusion of iron from the substrate into the coating.We also investigated mixtures of an Ni-Cr-B-Si matrix with TiC (Ti, W)C and NbC. The wear resistance against steel and SiC was measured. Various wear mechanisms and the properties of the carbide-matrix interface the wear results.     

Tribological properties of polymer nanohybrids containing gold nanoparticles obtained by laser ablation

We have studied polystyrene (PS)+Au particles nanohybrids. Approximately spherical gold nanoparticles with the average diameter of 15 nm were obtained by laser ablation in a liquid environment. Thus any chemical residue on the particles was eliminated. Focused ion beam (FIB) milling plus scanning electron microscopy (SEM) observation show that Au particles are fairly well dispersed inside the polymer matrix, better than when PS is simply dissolved in a nanoparticle solution. The Au particles concentration as low as 0.15 wt% results in dramatic changes in tribological properties, namely dynamic friction and pin-on-disk wear. Both wear and dynamic friction results are explained in terms of high brittleness of PS, abrasion of Au particles against a ceramic indenter, and also effects of density of filler particles in the matrix on tribological properties. Effects of varying normal load on friction are small.     

Ti6Al4V合金激光原位合成自润滑复合涂层高温摩擦学性能

为提高Ti6Al4V合金的高温摩擦学性能,采用激光熔覆技术在其表面原位合成多相混杂金属基高温自润滑耐磨复合涂层,熔覆粉末的成分为Ni60-16.8%TiC-23.2%WS_2(质量分数,下同),系统地研究复合涂层的显微组织、物相结构及其在20,300,600,800℃下的摩擦学性能和相关磨损机理。结果表明:复合涂层的显微硬度(701.88HV_0.5)约为基体(350 HV_0.5)的2倍;由于原位合成固体润滑相(Ti_2SC/TiS/NiS/TiO/TiO_2/NiCr_2O_4/Cr_2O_3)和硬质相(W,Ti)C_1-x/TiC/Cr_7C_3的协同作用,复合涂层的耐磨减摩性能明显优于基体。随着温度升高,涂层和基体的摩擦因数和磨损率均呈下降趋势,在800℃时复合涂层和基体的摩擦因数分别为0.32和0.43,磨损率分别为1.80×10^-4,2.92×10^-5mm/Nm。在800℃下塑性变形、分层和氧化磨损为基体主要磨损机理,复合涂层以氧化磨损和轻微的黏着磨损为主。     

CrNi3MoVA钢表面电火花沉积W-Ni-Fe-Co涂层的摩擦磨损性能

为进一步拓展火炮身管内膛强化手段,采用粉末冶金技术制备了W-Ni-Fe-Co合金,利用电火花表面沉积技术在CrNi3MoVA钢表面沉积了W-Ni-Fe-Co涂层,同时利用电镀技术在CrNi3MoVA钢表面制备了硬Cr涂层与之进行比较,用纳米压痕仪和摩擦磨损试验机研究了涂层的摩擦磨损性能,并利用XRD、SEM和EDS研究了沉积态和磨损后涂层的相结构、形貌及成分。结果表明电火花沉积W-Ni-Fe-Co涂层由α-W、γ-Fe和NiWO4组成,α-W在涂层中呈白亮带分布;W-Ni-Fe-Co涂层的硬度较电镀硬Cr涂层降低了18%,弹性模量较电镀硬Cr涂层提高了4%;W-Ni-Fe-Co涂层的磨损机制为轻微的粘着磨损,而电镀硬Cr涂层为严重的粘着磨损;CrNi3MoVA钢表面沉积W-Ni-Fe-Co涂层较电镀硬Cr涂层具有明显的减摩耐磨效果,随着摩擦速度的增加,W-Ni-Fe-Co涂层的摩擦系数降低,其原因是磨损表面氧化加剧,氧化物的自润滑作用加大。     

Preparation and high-temperature tribological properties of CrAlVYN-Ag nanocomposite coatings

CrAlVYN-Ag coatings were successfully deposited by introducing the elements of V and Ag into CrAlYN hard coatings. Their microstructure and mechanical property as a function of the annealing temperature were investigated from room temperature (RT) (～25°C) to 800°C. Besides, the worn surfaces were analyzed after combined effects of temperature and friction to figure out the wear mechanisms at different temperatures. The coatings exhibited special surface morphologies and Ag diffusion after annealing at different temperatures. In addition, the x-ray diffraction results showed that the coatings suffered obvious oxidation once the temperature exceeded 600°C; as a result of this, the coating hardness decreased sharply. The friction coefficients were relatively high during the tribological tests from RT to 400°C because the abrasive wear mechanisms played a dominant role. The lower friction coefficients obtained at 600 and 700°C were mainly due to the self-lubricating mechanisms. However, the coating exhibited higher friction coefficient at 800°C, which was mainly ascribed to the severe oxidation wear of the coating.     

2A12铝合金纳米复合微弧氧化陶瓷层摩擦学性能研究

研究2A12铝合金表面制备含纳米Si（）2颗粒复合微弧氧化陶瓷层,主要考察了不同尺度、不同类型纳米颗粒对陶瓷层摩擦学性能的影响规律。采用扫描电镜观察涂层表面形貌,CETR微米摩擦磨损试验机和白光干涉仪考察复合陶瓷涂层的耐磨性。结果表明,与未添加纳米颗粒的普通微弧氧化层相比,添加20nmSi02、80nmSi02、800nmSiO2后所形成的陶瓷涂层孔隙尺寸和数量均明显减小,并具有较高的耐磨性。     

Evaluation on tribological design coatings of Al2O3, Ni–P–PTFE and MoS2 on aluminium alloy 7075 under oil lubrication

The current work evaluated the friction and wear properties of tribological design surface coatings on aluminium alloy 7075 under various speed and nominal contact pressure. Hard-anodized Aluminium Oxide (Al₂O₃), burnished Refractory Metal Sulfide (MoS₂) and composite electroless nickel coatings with polytetrafluoroethylene (Ni–P–PTFE) particles were subjected to pin-on-disc sliding test against grey cast iron (GCI) under Mach 5 SL SAE 10 W-30 lubrication. The results indicated that Ni–P–PTFE composite coating possessed excellent friction–reduction capability but limited wear resistance due to low mechanical strength. Al₂O₃ coated sample showed outstanding wear resistance with high friction characteristic leading to high surface contact temperature. Furthermore, MoS₂ coating improved the wear resistance of the aluminium alloy.     

纳米颗粒大小对Ni-P合金镀层性能的影响及镀层制备工艺参数优化

为了提高农业刀具的使用寿命,在65Mn钢试件基体表面上,采用电沉积技术制备Ni-P-BN(h)纳米复合镀层,研究不同直径大小的BN(h)颗粒对镀层显微组织、硬度及摩擦磨损性能的影响;并通过正交试验,确定制备复合镀层的最优工艺参数。结果表明:随着BN(h)颗粒直径的增大,复合镀层有晶化的趋势;镀液中加入直径100 nm的BN(h)颗粒所制备的镀层表面胞体均匀致密、硬度最大、耐磨损性能最好;镀层形成过程中,纳米颗粒相互碰撞几率增大,导致晶核分布不均,影响表面质量并且减小耐磨损性能;制备Ni-P-BN(h)纳米复合镀层最优工艺参数为电流密度4.308 A/dm~2,BN(h)浓度15.00 g/L,施镀温度60℃,施镀时间3 h,所得硬度和磨损量分别为621.664 HV_(2N),2.665 8×10~(-3)mm~3,相较于65Mn基体硬度提升了1.2倍,磨损量降低86.5%。