含超细颗粒固液二相流对PSZ陶瓷与钢摩擦磨损特性的影响

在往复式摩擦磨损试验机上研究了含超细颗粒固液二相流对部分稳定二氧化锆（ＰＳＺ）陶瓷与ＧＣｒ１５钢滑劝副的摩擦磨损性能的影响。选择９０＾＃机械油和ＱＣ３０汽机油为基础油,分别加入五种超细固体颗粒,配制出不同浓度的２０种油样,分别在１６０１７０和１００℃温度下进行试验。结果表明：超细固体颗粒添加剂的用量、试验温度和基础油都影响陶与钢滑动副的摩擦磨损性能。对超细颗粒添加剂的润滑机理进行了初步探讨。     

Nano/Microtribological Properties of Ultrathin Functionalized Imidazolium Wear-Resistant Ionic Liquid Films on Single Crystal Silicon

Ionic liquids (ILs) are considered as a new kind of lubricant for micro/nanoelectromechanical system (M/NEMS) due to their excellent thermal and electrical conductivity. However, so far, only few reports have investigated the tribological behavior of molecular thin films of various ILs. Evaluating the nanoscale tribological performance of ILs when applied as a few nanometers-thick film on a substrate is a critical step for their application in MEMS/NEMS devices. To this end, four kinds of ionic liquid carrying methyl, hydroxyl, nitrile, and carboxyl group were synthesized and these molecular thin films were prepared on single crystal silicon wafer by dip-coating method. Film thickness was determined by ellipsometric method. The chemical composition and morphology were characterized by the means of multi-technique X-ray photoelectron spectrometric analysis, and atomic force microscopic (AFM) analysis, respectively. The nano- and microtribological properties of the ionic liquid films were investigated. The morphologies of wear tracks of IL films were examined using a 3D non-contact interferometric microscope. The influence of temperature on friction and adhesion behavior at nanoscale, and the effect of sliding frequency and load on friction coefficient, load bearing capacity, and anti-wear durability at microscale were studied. Corresponding tribological mechanisms of IL films were investigated by AFM and ball-on-plane microtribotester. Friction reduction, adhesion resistance, and durability of IL films were dependent on their cation chemical structures, wettability, and ambient environment.     

固体润滑剂在轴承上的应用研究

以水轮发电机轴承为应用研究实例，介绍了轴承镶嵌固体润滑剂的摩擦磨损机理，镶嵌轴承套的结构，固体润滑剂材料；并用摩擦学性能试验及台架模拟试验验证；在水轮发电机轴承上使用固体润滑剂可以提高润滑性能、降低摩擦系数，使摩擦副间能不断形成自补偿固体润滑转移膜，说明在重载，低速，摆动，间歇运动和泥水环境苛刻条件下工作的水轮发电机轴承使用固体润滑剂，比液体润滑具有更优越的性能。     

The Structural and Tribological Properties of MoS2-Ti Composite Solid Lubricants

MoS ₂ -Ti composite solid lubricant films were deposited on an AISI D2 tool steel and silicon wafer by CFUBMS (closed field unbalanced magnetron sputtering). The deposition process was performed for nine different test conditions at various levels of target current, working pressure, and substrate voltage using the Taguchi L ₉ (3 ⁴ ) experimental method. It was observed that the chemical composition of MoS ₂ -Ti composite films was significantly affected by sputtering parameters. It was determined that the microstructure of composite films is neither crystalline nor amorphous; in other words, it is quasi-amorphous, and (002) and (100) planes characteristic of MoS ₂ occurred. The friction coefficients of the films were determined over 1800 s and at a loading of 10 N by means of a pin-on-disk tribotester. The changes in friction coefficient were related to structural changes based on Ti addition and the different levels of deposition parameters.     

Ionic Liquid Lubricants: Basics and Applications

Interest in the tribological performance of ionic liquids (ILs) has increased significantly since they were first introduced as lubricants in 2001. The primary advantages of ILs over conventional lubricants lie in their better ability to form tribofilms, higher thermal stability, environmental friendliness, and adaptability to various applications. A remarkable reduction in friction and wear has been observed after the addition of ILs in oil- or water-based media and in grease, suggesting that ILs are promising candidate materials as neat lubricants as well as lubricant additives. Despite the relatively common utilization of ILs as lubricating media, their wider use is limited by their high cost and corrosive properties. This article provides a brief introduction to relevant IL structures and properties, focusing on recent applications of the materials in engineering tribology.     

Effect and mechanism of additives for ionic liquids as new lubricants

Ionic liquids are unique compounds, which exhibit low viscosity, non-flammability, low vapor pressure, and extremely high thermal stability. Therefore, they are expected as candidates for advanced lubricants. Several ionic liquids, derived from cations such as imidazolium, pridinium, ammonium, and anions such as , bis(trifluoromethylsulfonyl)imide (TFSI^-) were examined under boundary conditions. It was found that tribological properties of ionic liquids are better than those of conventional lubricants such as synthetic hydrocarbons, synthetic esters, and fluorinated ethers. Careful analysis of worn surface revealed that tribochemical reactions of ionic liquids take place under these conditions. For example, organic fluoride, iron fluoride, iron sulfate derived from anionic moiety of the ionic liquids were detected by the instrumental surface-analysis with TOF-SIMS and XPS. Tricresylphosphate (TCP) and dibenzyldisulfide (DBDS) were found to improve anti-wear properties of ionic liquids to some extent. Interestingly, both additive-derived compounds and anionic moiety derived ones were detected on the worn surface. Moreover, additive response of ionic liquids was found to be superior to those for conventional lubricants. It was speculated that the unique tribochemical reactions will lead us to design tailor-made lubricants. Lubrication mechanism of ionic liquids is discussed from the viewpoint of tribochemistry.     

Protic Ionic Liquids with Ammonium Salts as Lubricants for Magnetic Thin Film Media

The newly synthesized perfluoropolyether (PFPE) whose terminal group is an ammonium salt with a carboxylic acid has better frictional and anti-corrosion properties when compared to the conventional PFPEs. The friction is almost independent of the PFPE structure, but depends on the amine structures. This modified PFPE uniformly covers the magnetic surfaces; this is why it not only reduces the friction, but also has an effect on the corrosion resistance.     

柴油机磨损趋势预测

本文应用灰色系统理论的ＧＭ（１,１）预测模型,运用直读铁谱实验的数对柴油机磨损趋势进行了在线预测。重要的是,灰色系统理论－校正模型能够识别柴油机工况变化引起的直读铁数据的变化,正确判断其磨损趋势,实现对柴油机摩擦磨损趋势进行在线预测,其最大的特点是建模所需样本数据少,计算简单,预测准确。     

Tribological evaluation of α, -diimidazoliumalkylene hexafluorophosphate ionic liquid and benzotriazole as additive

Ionic liquids of α, -diimidazoliumalkylene hexafluorophosphate were synthesized. The tribological properties of the synthetic ionic liquid and the ionic liquid contained additive for contacts of steel/steel were investigated by Optimol SRV oscillating friction and wear tester under ambient conditions. The synthetic ionic liquid presented low friction coefficients and small wear volumes, especially under higher temperatures. The ionic liquid doped with benzotriazole (BTA) showed excellent anti-wear ability. The worn surfaces and chemical nature of the boundary films generated on the metal surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). SEM results showed slight abrasion on the worn surfaces and XPS results indicated the formation of FeF₂, FeF₃, Fe₃O₄, and FePO₄ by the tribochemical reactions of ionic liquid with iron during the sliding process.     

Tribological Testing and Thermal Analysis of an Alkyl Sulfate Series of Ionic Liquids for Use as Aerospace Lubricants

Due to their low vapor pressures, low melting points, high boiling points, high radiation resistance, and high thermal stability, room-temperature ionic liquids (ILs) appear to be suitable candidates as new aerospace lubricants for the upcoming return to the Moon and eventual Mars missions and for air and rotorcraft applications. In this study, three ILs with the same cation, 1-butyl-3-methylimidazolium, but different sulfate anions were tested using an ultra-high vacuum spiral orbit tribometer (SOT) and their thermal properties were determined by thermogravimetric analysis (TGA). Specifically, 1-butyl-3-methylimidazolium methyl sulfate, 1-butyl-3-methylimidazolium ethyl sulfate, and 1-butyl-3-methylimidazolium octyl sulfate were tested. The SOT experiments revealed that the lifetimes of the three ILs decreased with increasing alkyl substituent length on the sulfate anion. Infrared and Raman spectra were taken to detect unused ILs and graphitic degradation products, respectively, on worn parts. Post-run spectroscopic analysis indicated residual degraded, but still usable, ILs in all runs, coupled with varying amounts of amorphous graphitic material produced as the final degradation product of all ILs. SOT testing indicated that these ILs have lower friction coefficients and lifetimes greater than those of two commonly used perfluoropolyalkylether (PFPE) space lubricants. TGA showed that the methyl sulfate IL had the highest thermal stability in air and nitrogen. The vapor pressure of the methyl sulfate IL is as at least as low as Fomblin 815Z at 20°C.     

Tribological Characteristics of Imidazolium-based Room Temperature Ionic Liquids Under High Vacuum

Tribological characteristics of two imidazolium-based room temperature ionic liquids (RTILs), 1-hexyl-3-methylimidazolium tetrafluoroborate, and 1-hexyl-3-methylimidazolium hexafluorophosphate were investigated under high vacuum conditions. Viscosity–temperature characteristics and thermogravimetric characteristics of these compounds were also investigated. Imidazolium-based RTILs have relatively good viscosity–temperature characteristics that are comparable to those of multiply-alkylated cyclopentane (MAC). Thermogravimetric results showed that ionic liquids have high thermal stability and low vapor pressure. Ionic liquids showed low friction and low wear rate under high vacuum conditions, and high load-carrying capacity was observed.     

Friction and wear properties of duplex MAO/CrN coatings sliding against Si3N4 ceramic balls in air, water and oil

It is evident that the micro-arc oxidation (MAO) ceramic coatings often exhibit relatively high friction coefficients as sliding against many mating materials. To reduce the friction coefficient for the MAO coatings, the duplex MAO/CrN coatings were deposited on 2024Al alloy using combined micro-arc oxidation and reactive radio frequency magnetron sputtering. The microstructure and phase of the duplex coatings were observed and determined using scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The friction and wear behaviors of the duplex coatings sliding against Si₃N₄ balls in air, water and oil were investigated using a ball-on-disk tribometer. The wear rate of the duplex coating was determined by non-contact optical profilometer and the wear tracks on the duplex coatings were observed by SEM. The results showed the CrN coatings mainly consisted of Cr, CrN and Cr₂N phases. The duplex coatings/Si₃N₄ tribopair exhibited the highest friction coefficient in air, while displayed the lowest friction coefficient in oil. When the normal load and the sliding speed increased, the friction coefficient in air increased from 0.65 to 0.72, whereas decreased from 0.58 to 0.36 in water and 0.20 to 0.08 in oil. The specific wear rates for the duplex coatings in air were higher than those in oil. In comparison to the MAO coatings, the duplex MAO/CrN coatings displayed excellent tribological properties under the same conditions.     

A New Approach Using Palm Olein,Palm Kernel Oil,and Palm Fatty Acid Distillate as Alternative Biolubricants: Improving Tribology in Metal-on-Metal Contact

Metal-on-metal (MoM) hip replacements are commonly used hip implants. However, one of the issues under debate is the interference of friction and wear. The purpose of this feasibility study is to elucidate the performance of palm lubrication between the femoral head and the acetabular cup. In the tribology of hip implants, the use of palm olein, palm kernel oil, and palm fatty acid distillate as synthetic lubricants for human joints has shown tremendous potential. A modified pin-on-disc as hip screening has been used to evaluate the friction and wear on an acetabular cup with an inner diameter of 28 mm. The wear debris was then observed with microscopy image analysis. This study revealed that the physical and unique chemical properties in palm oil can optimize the rate of friction and wear on the metal acetabular cup and thus allow for a stable implant of MoM.     

柴油机曲轴的公理化设计

通过对公理化设计基本概念和设计过程的研究 ,提出了将公理化设计思想运用于柴油机曲轴设计的方法 ,建立了应用公理化设计进行曲轴设计的系统框架 ,开发了在UGII软件平台上进行公理化设计的软件系统。     

小波分析在柴油机监测信号处理中的应用

研究了小波分析在柴油机监测信号处理中的应用,提出了基于小波变换的特征提取方法。在简要讨论了小波变换及基本性质之后,探讨了利用小波分解序列的特征信息量确定信号特征频带的方法,并给出了分析实例。     

D150A柴油机气门正时的模拟计算

在一台单缸150柴油机性能方案计算优化的过程中,应用性能分析软件AVLBOOST建立了柴油机模型,在模型校准的基础上,针对该机排气门开启角较大这一状况,以满足功率、燃油消耗率等指标要求为目标,以气缸最高燃烧压力、排气温度为约束条件,对排气正时等进行了改进,为进一步提高柴油机的性能奠定了基础。     

系列磷酸酯水溶性离子液体在水中摩擦学行为研究

基于分子设计的理念,将辛醇、十二醇、十八醇分别与五氧化二磷反应得到不同链长的磷酸酯,再与二乙醇胺反应制备出3种水溶性离子液体润滑添加剂。采用红外光谱分析定性确认添加剂的结构,并应用热重分析3种添加剂的热稳定性。通过四球摩擦磨损试验机评价3种添加剂在水体系中的摩擦学性能。采用扫描电子显微镜(SEM)和X射线光电子能谱(XPS)对磨损表面进行表征分析,探讨其摩擦化学机制。结果表明:3种添加剂的热分解温度较高,分别为130、165、178℃;3种添加剂均能显著提高水体系的减摩抗磨和耐极压性能,且其抗磨和耐极压性能随着链长的增加而增强,这可能与添加剂的吸附能力和反应活性有关,烷基链较长的添加剂更容易吸附在金属表面,高载荷下能更快地与金属发生反应形成边界润滑膜;添加剂在表面形成的反应膜主要由铁氧化物,磷酸铁构成;边界润滑膜的存在提高了水体系的摩擦学性能,丰富了水作为润滑介质的使用场合。     

基于ANSYS的新型内摆线柴油机连杆部件有限元分析

以内摆线柴油机连杆为研究对象,考虑接触、装配预紧的影响,利用三维造型软件Pro/E建立连杆装配体的三维实体模型,导入有限元分析软件ANSYS中,建立一种更符合实际情况的有限元分析模型,并进行连杆组件强度的有限元计算,得出了连杆的变形、应力分布、强度情况。     

三元催化器在柴油机上的应用研究

机内净化技术是降低柴油机微粒与NOx排放的主要技术措施，但随着排放法规的日益严格，后处理成了一种必要。本文介绍了三元催化器的基本工作原理和特点，并根据发动机台架试验结果分析了三元催化器对内燃机动力性、经济性和排放的影响。     

A rig test to measure friction and wear of heavy duty diesel engine piston rings and cylinder liners using realistic lubricants

Laboratory tests to evaluate piston ring and cylinder liner materials for their friction and wear behavior in realistic engine oils are described to support the development of new standard test methods. A ring segment was tested against a flat specimen of gray cast iron typical of cylinder liners. A wide range of lubricants including Jet A aviation fuel, mineral oil, and a new and engine-aged, fully formulated 15W40 heavy duty oil were used to evaluate the sensitivity of the tests to lubricant condition. Test temperatures ranged from 25 to 100 °C. A stepped load procedure was used to evaluate friction behavior using a run-in ring segment. At 100 °C, all lubricants showed boundary lubrication behavior, however, differences among the lubricants could be detected. Wear tests were carried out at 240 N for 6 h at 100 °C with new ring segments. The extent of wear was measured by weight loss, wear volume and wear depth using a geometric model that takes into account compound curvatures before and after testing. Wear volume by weight loss compared well with profilometry. Laboratory test results are compared to engine wear rates.