Enhanced Anti-Wear Property of Low Viscosity Engine Oil for Sequence IVB Engine Test Meeting the GF-6 Specification

The purpose of this research is to determine the anti-wear capability of new advanced low viscosity engine oil to meet the Sequence IVB requirement of ILSAC GF-6 specification, which envisages that the first certification will be realized in 2020. The anti-wear performance of the aged candidate GF-6 engine oils was evaluated using the laboratory bench test rigs such as the Falex Pin & Vee Block test machine and the high frequency reciprocating rig (HFRR). The worn surfaces were analyzed by X-ray photoelectron spectroscopy (XPS). The remarkable anti-wear performance of the developed GF-6 engine oil was also confirmed in the Sequence IVB test. The results indicate that by appropriately selecting and balancing the calcium detergent additives the wear loss of cam and tappet determined in the Sequence IVB test at low temperature could be significantly reduced. The time for occurrence of the intersection of the base and acid values corresponds well with the increase of wear of cam tappet of the IVB engine test.

Tribological Testing of Hemispherical Titanium Pin Lubricated by Novel Palm Oil:Evaluating Anti-Wear and Anti-Friction Properties

In this study, the properties of hip implant material and lubricants were examined using a pin on disc apparatus, to compare the effect of metal-on-metal （MoM） contact with a bio-lubricant derived from palm oil. The behaviour of the lubricants was observed during the experiments, in which a hemispherical pin was loaded against a rotating disc with a groove. A titanium alloy was used to modify the hemispherical pin and disc. Before and after the experiments, the weight and surface roughness were analysed, to detect any degradation. The results were compared according to the different kinematic viscosities. The wear rates and level of friction with each lubricant were also examined. The lubricant with the highest vis- cosity had the lowest frictional value. Therefore, develop- ing suitable lubricants has the potential to prolong the lifespan of prostheses or implants used in biomedical applications. The experiments collectively show that lubricants derived from palm oil could be used as efficient bio-lubricants in the future.

Surface Modified TiO2 Nanoparticles-an Effective Anti-wear and Anti-friction Additive for Lubricating Grease

The surface modified TiO_2 nanoparticles were prepared by using 12-hydroxystearic acid chemically modified on the TiO_2 surface. The average size of the TiO_2 particles is about 30 nm. The optimum ratio of tetrabutyl titanate to 12-hydroxystearic acid was 1/0.5. The bonding form between 12-hydroxystearic acid and TiO_2 nucleus was investigated by FTIR, DSC, TGA and XRD techniques. The lubricating grease containing the surface modified TiO_2 nanoparticles possesses excellent anti-wear and anti-friction properties. Compared with the grease without TiO_2, the PB value can be increased by 52% as the best performance of the grease containing surface modified TiO_2 nanoparticles, while the friction coefficient can be reduced by 33% with the addition of a small amount of TiO_2 nanoparticles, and meanwhile the wear scar diameter decreases by 25%.

Friction-reducing,Anti-wear and Self-repairing Properties of Sulfonated Graphene

The friction reducing properties of sulfonated graphene as a lubricating additive were investigated using a four-ball machine tester with high carbon chromium bearing steels GCr15（SAE52100） friction pairs. The microscopic morphology, elemental composition, and self-repairing properties were observed and analyzed by using scanning electronic microscopy（SEM）, X-ray diffraction（XRD） and digital microscopy. The relationships among sulfonated graphene ethanol solution concentration, friction coefficient, and abrasion loss were revealed. It was found that the optimal concentration of ethanol solution with the addition of sulfonated graphene was 0.15g/m L and the coefficient of friction was only 0.105 under certain condition. Then the stable chemical properties and good anti-corrosion properties of the metal-graphene layer were further confirmed using salt spray corrosion test. In summary, sulfonated graphene can be used as a new kind of self repairing additive, and it has excellent wear-resistant and self-repairing performances.

The Lubricating Effectiveness of S-Mo Extreme Pressure Additive and Its Anti-wear Mechanism

A kind of novel compound containing S and Mo elements was synthesized. Its chemical structure was characterized by elemental analysis, IR and 3MR. hs anti-wear property and the load-carrying capacity, as an extreme pressure （EP） additive of lubricating oil, were investigated using a four-bull tester. The experimentul results show that the additive exhibits a superior anti-wear property and a high load-carrying capacity . The presence of other additives does not interfere with the anti-wear prnperty of the extreme pressure additive. The influences of load and temperature on the propert） of the additive were examined. The possible mechanism uas investigated by means of sufface analysis of the tested steel ball specimen , using XPS. The lubricatian films formed on the rubbing surface are mainly composed of MoS2, MoO3 and MoO2.

Study on Friction Reducing and Anti-wear of CaCO_(3) Nanoparticles as Additives in Lubricating Oils

This paper has insepected the size and the structure of the calcium carbonate (CaCO3) particles by adopting X-ray diffraction and transmission electron microscope (TEM). The suitable surfactants have been selected and put into lubricating oil with nanometer CaCO3 particles. By testing some parameters, such as the maximum non-seizure load, the shape and diameter of wear scar, the friction factor, the nanometer CaCO3 particles’ properties of extreme pressure, anti-wear and friction reduction have been tested and analyzed. The properties of the nanometer CaCO3 particles’ tribology chemistry have been analyzed through X-ray photoelectron spectrum (XPS) test. Also the nanometer CaCO3 particles’ mechanism of anti-wear and friction reduction has been studied systematically. The research results show that, the lubricating oil with nanometer CaCO3 particles have good tribological properties.

Ashless Anti-Wear Additives for Motor Oils

Ashless anti-wear(AW) additives containing phosphorus can be used as partial or complete replacement of zinc dithiodialkylphosphate(ZDDP).In oils with low sulfated ash content(< 1.0%),this approach will allow a significant reduction of ash content and/or provide the formulator with more flexibility to use additional metallic detergents.Over the past 70 years or so,ZDDP has proven to be a very effective engine oil additive by helping to reduct oxidation,wear,and corrosion in service.In this paper,we will compare ZDDP-based lubricants with lubricants base on ashless,P-containing additive systems;we will describe the ashless chemistry investigated and discuss its contribution to wear performance in modern,low-SAPS(sulfated ash,phosphorus & sulfur) engine oils in various bench,rig and engine tests;we will also report on some work done to evaluate AW additive compatibility with modern three-way exhaust gas catalysts(TWC).

In-situ formation of nitrogen doped microporous carbon nanospheres derived from polystyrene as lubricant additives for anti-wear and friction reduction

This study presents a nitrogen-doped microporous carbon nanospheres(N@MCNs)prepared by a facile polymerization–carbonization process using low-cost styrene.The N element in situ introduces polystyrene(PS)nanospheres via emulsion polymerization of styrene with cyanuric chloride as crosslinking agent,and then carbonization obtains N@MCNs.The as-prepared carbon nanospheres possess the complete spherical structure and adjustable nitrogen amount by controlling the relative proportion of tetrachloromethane and cyanuric chloride.The friction performance of N@MCNs as lubricating oil additives was surveyed utilizing the friction experiment of ball-disc structure.The results showed that N@MCNs exhibit superb reduction performance of friction and wear.When the addition of N@MCNs was 0.06 wt%,the friction coefficient of PAO-10 decreased from 0.188 to 0.105,and the wear volume reduced by 94.4%.The width and depth of wear marks of N@MCNs decreased by 49.2% and 94.5%,respectively.The carrying capacity of load was rocketed from 100 to 400 N concurrently.Through the analysis of the lubrication mechanism,the result manifested that the prepared N@MCNs enter clearance of the friction pair,transform the sliding friction into the mixed friction of sliding and rolling,and repair the contact surface through the repair effect.Furthermore,the tribochemical reaction between nanoparticles and friction pairs forms a protective film containing nitride and metal oxides,which can avert direct contact with the matrix and improve the tribological properties.This experiment showed that nitrogen-doped polystyrene-based carbon nanospheres prepared by in-situ doping are the promising materials for wear resistance and reducing friction.This preparing method can be ulteriorly expanded to multi-element co-permeable materials.Nitrogen and boron co-doped carbon nanospheres(B,N@MCNs)were prepared by mixed carbonization of N-enriched PS and boric acid,and exhibited high load carrying capacity and good tribological properties.

Bionic Coupling of Hardness Gradient to Surface Texture for Improved Anti-wear Properties

This work investigates the potential of combining hardness gradient with surface texture （an example of bionic coupling） to improve anti-wear properties. The bionic coupling of hardness gradient and Hexagonal Texture （HT） was achieved by laser heat treatment on steel specimens with pre-engraved hexagonal surface texture. The successful establishment of decreasing hardness from surface to internal bulk was verified by hardness measurements along the depth of cross-sectioned specimens and corre- lated with the observations from metallurgical microscopy. The tribological performance of bionic coupling specimens （HT-L） was examined under dry contact condition, together with respective control specimens of individual bionic features, e.g. HT-H （of similar surface hardness generated by conventional heat treatment but without hardness gradient） and SS-L （of smooth surface treated by the same laser processing as for HT-L）. It is found that HT-L not only exhibits lower friction coefficient and less friction fluctuation than HT-H and SS-L, but also demonstrates a 〉50% reduction of wear loss compared to HT-H and SS-L （0.0343 g for HT-L vs. 0.0723 g for HT-H, P〈0.001; 0.0343 g for HT-L vs. 0.0817 g for SS-L, P〈0.001）. Corroboratively, observations with scanning electron microscopy revealed a relatively smooth surface for worn HT-L specimen, contrasting with the rugged and grooved surfaces of worn HT-H and SS-L specimens. These results indicate that the bionic coupling of hardness gradient to hexagonal texture can indeed improve anti-wear properties, affording a new strategy to wear and friction manage- ment.

Anti-wear properties on 20CrMnTi steel surfaces with biomimetic non-smooth units

In order to gain a sufficient wear resistance for applications, the biomimetic non-smooth units in concave were fabricated on the surfaces of 20CrMnTi steel using a biomimetic laser remelting technology. The diameter and distribution of the concaves were optimized using orthogonal experiment. The microstructures of the biomimetic non-smooth units were examined. The anti-wear behaviors were investigated by the rolling wear test with lubricant. The results of wear tests indicated that the biomimetic surfaces exhibit a higher anti-wear ability than the smooth surfaces. The biomimetic surface with concaves of 250 μm in diameter and transverse distance of 270 μm and longitudinal distance of 400 μm exhibits the best anti-wear property. The enhancement of wear resistance can be mainly attributed to the action of biomimetic non-smooth units and the super fined microstructure and hardness in the biomimetic unit zones.

Isosteric design of friction-reduction and anti-wear lubricant additives with less sulfur content

To reduce harmful sulfur content in lubricant additives, making use of isosterism has been shown to be an effective strategy. When thiobenzothiazole compounds were used as templates, the exchange of sulfur atoms in the thiazole ring with oxygen atoms and NH groups produced twelve isosteres. Similarly, 2-benzothiazole- S-carboxylic acid esters were used as template molecules to produce six isosteres. About 30% of the isosteres exhibited a satisfactory deviation of ±5% relative to the template, ignoring the specific changes in the base oils, the differences in molecular structure, and the friction or wear properties. The template molecules and isosteres in triisodecyl trimellitate exhibited better tribological properties than in trimethylolpropane trioleate or bis(2- ethylhexyl) adipate. Comparative molecular field analysis(CoM FA)- and comparative molecular similarity index analysis(CoMSIA)-quantitative structure tribo-ability relationship(QSTR) models were employed to study the correlation of molecular structures between the base oils and additives. The models indicate that the higher the structural similarities of the base oils and additives are, the more synergetic the molecular force fields of the lubricating system are; the molecular force fields creating synergistic effects will improve tribological performance.

Anti-wear beam effects on gas-solid hydrodynamics in a circulating fluidized bed

Anti-wear beams installed on water walls of circulating fluidized bed （CFB） boilers are one of the most effective ways to protect against water-wall erosion. Beam effects from, for example, beam size and superficial gas velocity were investigated on gas-solid hydrodynamics in a CFB test rig using CFD simulations and experimental methods. The downward flow of the wall layer solids is observed to be disrupted by the beam but is then restored some distance further downstream. When falling solids from the wall layer hit the anti-wear beam, the velocity of the falling solids decreases rapidly. A fraction of the solids accumulates on the beam. Below the beams, the falling solids have reduced velocities but upward-moving solids were observed on the wall. The effect of the beam increases with width and superficial gas velocity. Wear occurs mainly above the beam and its variation with width is different above to below the beam. There is an optimum width that, when combined with beam height, results in less erosion.

New starch capsules with antistatic,anti-wear and superlubricity properties

Adsorption of drug powder is caused by triboelectrification on the surface of starch capsule during filling process.Furthermore,high wear rate and poor water lubricity also hinder the further practical applications of traditional starch capsule.To solve these problems,a glycerol-modified starch capsule with perfect anti-triboelec-trification and enhanced lubrication performance was fabricated.Hydrogen bond between glycerol and starch molecules could reduce the bound water content on the capsule surface and thus realizes anti-triboelectrification.By adding glycerol,a three-tier structure composed of starch-glycerol-water is formed through hydrogen bonding on the surface of the starch film,which has been proven to be favorable for lubrication performance.When 5% glycerol is added,the short-circuit current(I_(sc))of starch-based triboelectric nanogenerator(TENG)is reduced by 86%,and the wear volume of the starch film is reduced by 89%.Underwater lubrication condition,the lubrication performance of the starch-glycerol film can reach the super lubricated level with a friction coefficient of about 0.005.This work provides a new route to obtain modified starch capsules with improved anti-triboelectrification property,reduced wear rate and superlubricity property.

Restoration of enamel anti-wear properties via remineralization: Role of occlusal loading

In this in vitro study,the restoration of acid-eroded enamel surface morphology and anti-wear properties under two conditions,mono-remineralization(treated with remineralization alone)and impact-remineralization(treated with cyclic impact followed by remineralization),are characterized to determine the effect of occlusal loading on enamel remineralization.Compared with the mono-remineralized surface,the impact-remineralized surface demonstrates better anti-wear performance,as manifested by a higher hardness and elastic modulus,as well as a lower friction coefficient and wear volume.Loading on the eroded enamel surface induces the fragmentation of hydroxyapatite nanoparticles,which aids crystal deposition and fusion during subsequent remineralization.In summary,owing to the enamel microstructure,occlusal loading can promote the restoration of enamel anti-wear properties by enhancing remineralization.Remineralization enhancement through occlusalloading-induced nanoparticle fragmentation plays a significant role in preventing human teeth from excessive wear.

基于氢谱修饰指数的润滑油添加剂抗磨损性能的预测研究

润滑油添加剂对保障机械运行的稳定性和安全性、延长设备的使用寿命、节约能耗具有重要作用,由于通过实验获得数据费时费力,故用定量结构摩擦性能关系研究方法,来获取抗磨损性能数据成为一种简便而高效的方法.为研究酰肼类及磷酸类润滑油添加剂抗磨损性能与结构的关系,定义并建构了新的氢谱修饰指数^(0)H,并计算36个酰肼类及磷酸类分子的电性距离矢量,筛选了M_(2)、M_(3)、M_(21)和M_(59),将这5个结构描述符作为BP神经网络的输入变量,磨损体积量度V s作为神经网络输出变量,用5-3-1的神经网络结构,构建了神经网络法预测模型,模型相关系数0.944,磨损体积量度V s的预测值与文献实验值的平均相对误差为2.61%,优于文献方法结果.结果表明:酰肼类及磷酸类润滑油添加剂抗磨损性能与氢谱修饰指数有良好的非线性关系,影响抗磨损性能的主要因素是分子中原子特性、基团片段的—CH_(3)、—CH_(2)—、>CH—、—O、—N—和—P—等.该研究对指导合成新型抗磨损性能好的化合物分子有理论意义.

内燃机活塞环材料及表面处理技术研究现状与发展趋势

活塞环是内燃机中重要的零部件之一,该部件的摩擦损耗占内燃机总摩擦损失的26%。因此,活塞环材料的选用及其表面处理研究对于优化提升内燃机性能、延长服役寿命具有重要意义。简单介绍并总结了内燃机活塞环常用材料及其发展趋势,详细综述了激光表面织构技术、表面涂层技术以及表面复合技术在内燃机活塞环减摩抗磨方面的研究和应用现状。其中,激光表面织构技术(LST)可起到接纳磨屑、保持油膜等作用,从而降低活塞环表面摩擦和磨损,但由于织构形貌和几何参数特征对摩擦学性能的影响较为复杂,仍需结合实际工况进一步研究并优化。以镀铬、热喷涂、气相沉积及激光熔覆为代表的涂层技术也常用于活塞环的表面强化处理,但涂层材料种类繁多,难以形成统一的行业标准进而规模应用。此外,通过合理复合多种表面处理技术,比如微弧氧化与电泳沉积复合、超声滚压与离子渗氮技术复合、磁控溅射和低温离子渗硫复合等,可实现优势互补、发挥协同作用,有效改善接触表面的摩擦性能,为活塞环的减摩增寿研究开拓了新的思路。最后对未来活塞环材料开发应用及其减摩抗磨方面的研究发展进行了展望。

超低剂量CI-415W-40柴油机油的研制及应用

基于我国社会经济和汽车工业的发展现状,未来一段时间内,市场中高、中、低档柴油机油将保持并存的局面,CI-4柴油机油仍是市场的主体,占有30%以上的份额。因此,为提高CI-4柴油机油性价比,优选以性能优异的金属清净剂、无灰分散剂和抗氧抗腐、抗磨剂等研制的复合剂,以8.3%的加剂量应用于适宜的基础油中,所调制的CI-415W-40柴油机油通过了Mack T-8E、Cat.1K、Cat.1P、程序ⅢF、Mack T-12、RFWT、EOAT和Cummins ISM等发动机台架试验,产品质量满足API CI-415W-40柴油机油标准的要求,并可实现6万km换油。

Enhancing the Tribological Performance of Conductive Grease Through the Modification of Polypyrrole with Ionic Liquids

This study prepared four types of ionic liquid-modified polypyrrole(IL-modified PPy)as conductive additives and investigated their tribological performance and conductivity in polytetrafluoroethylene lubricating grease.The results indicated that IL-modified PPy effectively enhanced the anti-wear performance and conductivity of the base grease.Among the additives,1-octyl-3-methylimidazolium tetrafluoroborate([OMIm][BF4])modified PPy showed superior performance compared to the other three additives,with the best effect observed at a mass fraction of 0.5%.X-ray photoelectron spectroscopy analysis revealed that IL-modified PPy forms a stable friction chemical film during the friction process,effectively enhancing the lubrication performance and conductivity of the base grease.This indicates broad potential applications in the field of conductive lubrication.

电机轴承用全氟聚醚润滑脂的研制与性能

研制了一种电机轴承用全氟聚醚润滑脂。通过对基础油,稠化剂和添加剂的考察,确定了电机轴承用全氟聚醚润滑脂由全氟聚丙醚基础油,聚四氟乙烯稠化剂,3%白炭黑,3%有机含锌盐抗磨极压剂,3%硫化异丁烯抗磨极压剂,2%纳米碳酸钙和3%有机硼酸酯抗磨极压剂组成。研制的电机轴承用全氟聚醚润滑脂的磨斑直径为0.41mm,烧结负荷P_(D)值达到7846N,最大无卡咬负荷值达到1961N,制备的全氟聚醚润滑脂与橡胶的相容性良好,达到了研制目标。(图4表9参考文献10)

橡胶减摩抗磨改性研究进展

橡胶因具有优异的理化性质及独特的力学性能而广泛应用于国防、航空航天、医用、交通、建筑及机械电子等领域,起到减震、缓冲和密封等作用.摩擦学性能是橡胶材料的重要指标之一,然而橡胶自身具有较高的摩擦系数,在一些应用领域,如活塞杆、阀轴(杆)密封、轮胎和水润滑轴承等,因黏连、摩擦生热、机械磨损及磨粒磨损等原因导致性能下降甚至失效.本文中首先综述了橡胶摩擦及磨损理论,随后从橡胶基体改性、橡胶表面处理以及表面织构化3个方面介绍了橡胶减摩抗磨改性方法的研究进展,并对其发展前景进行了展望.