有机钼化合物与二烷基二硫代磷酸锌的抗磨协同效应

采用四球机评价了二烷基二硫代磷酸钼(MoDDP)、二烷基二硫代氨基甲酸钼(MoDTC)和非活性有机钼等3种有机钼化合物的抗磨性能,及其与二烷基硫代磷酸锌(ZnDDP)的抗磨协同效应.结果表明:这3种化合物都具有良好的抗磨性能,尤以MoDDP为最佳;3种有机钼化合物与ZnDDP在石蜡基基础油中都展现出良好的抗磨协同效应,尤其以MoD代和非活性有机钼为佳.     

含磷摩擦改进剂的抗磨协同性能研究

利用四球试验机评价了含磷摩擦改进剂TPO与两种二烷基二硫代磷酸锑(SbDDP1、SbDDP2)、二烷基二硫代氨基甲酸锑(SbDDC)、硫化二烷基二硫代磷酸氧钼(MoDDP)共4种添加剂的抗磨性能以及它们之间的抗磨协同作用.结果表明,TPO、SbDDP和MoDDP都具有较好的抗磨性能,其中MoDDP最佳.当TPO分别与上述4种添加剂复合后,均表现出了不同程度的抗磨协同效应,其中TPO与SbDDP2和SbDDC的协同效果较好,尤其是复配浓度达到最佳比例时,协同效果最佳.     

Effects of molybdenum dithiocarbamate and zinc dialkyl dithiophosphate additives on tribological behaviors of hydrogenated diamond-like carbon coatings

The tribological behaviors of hydrogenated diamond-like carbon (DLC) coatings under varied load conditions lubricated with polyalpha olefin (PAO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyl dithiophosphate (ZDDP) additives were investigated in this paper. Hydrogenated DLC coatings were synthesized through the decomposition of acetylene by the ion source. The tribological performances were measured on a SRV tribometer. The morphologies and chemical structures of the DLC coatings were investigated by the scanning electron microscope (SEM), Raman spectrometer (Raman) and X-ray photoelectron spectroscope (XPS). It was shown that the low friction and high wear were achieved on the hydrogenated DLC coating under MoDTC lubrication, while low wear was found on the hydrogenated DLC coating lubricated by ZDDP. The primary reason was attributed to different tribofilms formed on the contact area and the formation of graphitic layer. Both factors working together leaded to quite different tribological behaviors.     

二硫化钼填充聚酰亚胺复合材料的摩擦学性能

利用MM-200型摩擦磨损试验机,对不同体积含量MoS2填充聚酰亚胺（PI）复合材料在干摩擦条件下与GCr15轴承钢对摩时的摩擦磨损性能进行了研究,并利用扫描电子显微镜对PI复合材料及其偶件的磨损表面进行了分析。研究发现,添加MoS2可有效降低PI复合材料的摩擦系数,且PI复合材料的摩擦系数随MoS2含量的增大而减小。除PI＋10％MoS2外,其它含量MoS2填充PI复合材料的耐磨性能均明显优于纯PI材料,但当MoS2的含量超过30％后,PI复合材料的磨损率基本不随MoS2含量变化。在较高的载荷条件下,MoS2填充PI复合材料均呈现出良好的减摩耐磨性能。     

Tribological properties of dispersed carbon nanotubes in lubricant

This study examined the tribological properties of two lubricating oils, mobil gear 627 and paraffinic mineral oils, with multi-walled carbon nanotubes (MWCNTs) nanoparticles used as additives with various concentrations (0.1, 0.5, 1, and 2 wt.%). The friction and wear experiments were performed using a four ball tribotester. The samples were tested for their anti-wear, load carrying capacity, and friction coefficients according to ASTM D-2783, ASTM D-2596, and ASTM D-5183 standards. The experimental results show that the addition of MWCNTs to base oils exhibit good friction reduction and anti-wear properties. The wear test results show a decreased wear by 68% and 39% in the case of MWCNTs-based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. Furthermore, the friction reduction results show a decrease of friction about 57% and 49% in the case of MWCNTs-based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. The weld load of the base oil containing 1% MWCNTs was found to be 400 kgf and 125 kgf as compared with base mobil gear 627 and paraffinic mineral oils, respectively, which got welded at 200 kgf and 100 kgf. The morphologies and typical element distribution of the worn surfaces were characterized by scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). The SEM micrographs and EDX chemical analysis confirm the formation of a tribolayer composed of the elements from the nanoparticles.     

Nanodiamond-based nanolubricants for motor oils

Over the last few years, interest in applications of nanoparticles as lubricant additives has steadily grown due to the demonstrated reduction in friction and wear of nanoparticle-containing lubricant formulations (so-called nanolubricants). Particularly, studies of motor oils containing a “green” all-carbon additive, detonation nanodiamond (DND) particles, revealed their positive impact on the performance of lubricant compositions and fuel economy in engine tests. In the current review we discuss critical issues toward successful implementation of DND in nanolubricants: role of DND structural characteristics, stability of colloids of DND in oils, DND compatibility and synergism with other additives in commercial oils, mechanisms of DND impact on the properties of lubricants. Owing to the abrasive nature of diamond, DND-based nanolubricants must be carefully engineered in order to avoid increased wear of the friction surfaces and get full benefit from significantly reduced friction of well-polished surfaces.     

基于再生基础油的CF-4 10W/30柴油机油的研制

废机油在预处理后,采用分子蒸馏设备对其进行了蒸馏分离,得到的轻组分再进行加氢精制,生成再生润滑油。元素分析显示精制前后硫含量下降约66.3%。以再生润滑油与68#机械油调和成再生基础油,作为柴油机油的基础油。实验结果表明,再生基础油的抗磨性较好,这与再生基础油中残存的少量抗磨剂有关。再生基础油的抗氧化安定性不佳,是由于精制过程中脱除了油品中的抗氧化成分—含硫多环化合物,可通过添加苯三唑衍生物T551等金属减活型抗氧剂来改善。再生基础油的起泡性较大,需加大抗泡剂用量。研制的CF-4 10W/30柴油机油,其抗磨性、倾点等优于参比油,其它性能相当,完全可以作为商用柴油机油使用。     

铈掺杂白云母复合粉体的制备及其减摩抗磨机理

采用机械力固相化学反应法制备了稀土铈掺杂白云母(Muscovite,MC)的复合粉体(Ce-MC),表征了粉体的微观形貌、晶体结构、元素组成和粒径分布。利用四球摩擦磨损试验机考察比较了MC和Ce-MC作为润滑脂添加剂的摩擦学性能,对磨损表面进行了SEM、EDS和XPS分析,并探讨了Ce-MC的减摩抗磨机理。结果表明:CeMC复合粉体中铈化合物包覆在白云母粉体表面,主要物相为CeO_2;Ce-MC和MC作为添加剂均能提高锂基润滑脂的减摩抗磨性能,且Ce-MC复合粉体的摩擦学性能优于MC单体;Ce-MC优良的摩擦学性能与其磨损表面Ce-MC的物理吸附膜和主要成分为Fe_2O_3、SiO_2的化学反应膜有关。     

不同相态液晶添加剂的润滑性能及机理分析

为了研究液晶化合物作为润滑添加剂的摩擦学性能及其作用机理,考察了2种向列相液晶和2种胆笛相液晶在矿物基础油中的摩擦学性能,比较了不同结构添加剂抗磨减摩性能的差异并分析了原因,在此基础上简述了液晶化合物的不同相态对于润滑性能的作用机理。结果表明:加入1%的液晶添加剂均可明显改善基础油的润滑性能;向列相液晶添加剂由于分子结构刚性更强,利于增加油膜强度以避免干摩擦产生;而胆备相液晶添加剂分子呈片层、螺旋结构,柔性链易适应磨痕,在同等载荷下有着更好的抗磨效果。     

PA6/PP复合材料吸水性及摩擦磨损性能研究

尼龙6具有良好的耐磨性,由于自身的吸水性而限制了其应用.本工作采用多单体接枝增容聚合物共混新技术,利用烯烃类聚合物自身的润滑性、以及耐吸水性,通过与尼龙6复合来改善尼龙6的吸水性和摩擦磨损性能.将自制的PP-g-(MAH-co-St),PP-g-(GMA-co-St)和PP-g-(MMA-co-St)三种相容剂添加到PA6/PP共混物中,熔融挤出造粒,注塑成型,制得PA6/PP为80/20的不同相容剂增容的聚合物共混物.研究了不同相容剂对PA6/PP共混合金吸水性和摩擦磨损性能的影响.结果表明:自制的三种相容剂都能够在不同程度上改善PA6/PP共混材料的吸水性.其中,PP-g-(GMA-co-St))对PA6/PP共混体系增容、耐水性及耐磨性改善效果最好.     

Friction and wear of Cr-doped DLC films under different lubrication conditions

In this paper, Cr-doped DLC films with various Cr contents were deposited on stainless steel plates by an ion beam deposition/magnetron sputtering hybrid method and the tribological performance of the samples was evaluated using a ball-on-disk tribometer. It was found that the influence of the Cr content in the Cr-doped DLC films on the friction coefficient when lubricated by PAO, 150SN, PAO + T307, or 150SN + T307 is insignificant while the friction coefficient of the Cr-doped DLC films under PAO + MoDTC or 150SN + MoDTC lubrication can be significantly reduced through the introduction of Cr at an optimum level into DLC films. The wear resistance of the DLC films under PAO, 150SN, PAO + MoDTC, or 150SN + MoDTC lubrication can be improved by the introduction of Cr into DLC films; but Cr doping is unbeneficial to the wear resistance of DLC films lubricated by PAO + T307 or 150SN + T307.     

利用电化学技术制备白钨矿薄膜的生长动力学研究

采用恒电流电化学技术直接在金属钼(Mo)或钨(W)片上制备了白钨矿钼酸盐、钨酸盐AMO4(A=Ba、Sr、BaxSr1-x、BaxSryCa1-x-y;M=W、Mo)晶态薄膜,制备时间分别为从薄膜开始生长到薄膜生长结束的不同时间间隔.利用场发射扫描电镜(FESEM)和电子能谱仪(EDX)等测试手段,分别对这些薄膜的生长特性进行了测试,并对测试结果进行了对比分析.结果表明,利用电化学技术制备白钨矿薄膜时,金属基片在不断的溶解;由于负离子配位多面体的沉积、构架和阳离子的不断填充,完成晶核的形成和晶粒的长大;随着时间的增加,光滑饱满的晶粒布满整个基片表面从而完成了薄膜的成膜过程;由于阳离子Ba2+、Sr2+、Ca2+填充速率依次降低,使得在沉积二元和三元薄膜时出现富钡现象.     

Tribological properties of fluorinated graphene reinforced polyimide composite coatings under different lubricated conditions

The tribological properties of polyimide (PI) and PI/fluorinated graphene (FG) nanocomposites, as a new class of graphene reinforced polymer, are investigated using a ball-on-disk configuration under different lubricated conditions of dry sliding, water lubrication and oil lubrication. Experimental results reveal that single incorporation of FG can effectively improve the tribological performance of PI under all the three conditions. In addition, compared to the results under dry sliding, the phenomenon that the friction coefficient decreases while the wear rate increases under water lubrication condition is observed and researched in detail. The worst anti-wear performance under water-lubricated condition can be ascribed to the fact that the water can be adsorbed by the polar imide radicals of the PI and PI/FG nanocomposite, therefore leading to the property deterioration of the PI and PI/FG nanocomposite coatings.     

Applications of carbon quantum dots in lubricant additives: a review

Advances in lubricants are vital to the pursuit of energy efficiency and sustainable development. It is well known that the essence of lubricating oil is lubricant additives, especially the friction-reducing and anti-wear additives. Carbon quantum dots (CQDs), a novel zero-dimensional carbon-based nanomaterial, have attained growing expectations in material and chemical sciences because of their extraordinary properties such as low toxicity and environmentally friendly, high chemical and thermal stability, and good designability. Since their discovery, CQDs have shown great potential in many applications including sensors, medicine, photovoltaic devices, biology, and tribology. The latest application of CQDs as the high-performance friction-reducing and anti-wear additives has garnered increasing attention. With the in-depth study, CQDs have gradually exhibited their excellent tribological properties, especially acted as additives in lubricating base oils. This paper has reviewed the progress in the research and development of CQDs-based lubricant additives by introducing lots of successful applications of CQDs-based additives in the present work and then highlighted the friction-reducing and anti-wear property, superiority, as well as the lubrication mechanism of CQDs as an additive, along with some discussion on challenges and perspectives in this significant and promising field. Finally, we offered a series of suggestions for developing the next-generation high-performance CQDs-based lubricant additives.

Graphical abstract

This work presented the carbon quantum dots as the lubricant additives of lubricating base oils.

     

Friction and wear studies of polyimide composites filled with short carbon fibers and graphite and micro SiO2

Polyimide (PI) composites filled with short carbon fibers (SCFs), micro SiO₂, and graphite (Gr) particles were prepared by means of hot press molding technique. The friction and wear properties of the resulting composites sliding against GCr15 steel were investigated on a model ring-on-block test rig. Experimental results revealed that single incorporation of graphite and SCF significantly improve the tribological properties of the PI composites, but micro SiO₂ was harmful to the improvement of the friction and wear behavior of the PI composite. It is found that a combinative addition of Gr, SCF and micro SiO₂ was the most effective in improving the friction-reducing and anti-wear abilities of the PI composites. Research results also show that the filled PI composites exhibited better tribological properties under higher PV-product.     

两种硫化锑纳米材料在液体石蜡中摩擦学性能的对比研究

利用四球摩擦磨损试验机对硫化锑纳米棒束作为液体石蜡添加剂的摩擦学性能进行了研究. 结合硫化锑纳米颗粒的性能, 对比分析两者作为添加剂润滑下摩擦系数、磨斑直径、钢球磨损表面形貌的变化规律, 并得到以下结论: 两种材料均能在一定程度上改善基础油的减摩抗磨性能, 在低载荷时硫化锑纳米棒束的减摩抗磨性能明显优于纳米颗粒, 较高载荷时, 两者的减摩抗磨性能相当; 就承载能力而言, 纳米颗粒的性能明显优于纳米棒束; 低载时纳米棒束的“微滚珠”效应是其优异摩擦学性能的主要原因.     

磨损失效发动机再制造可行性分析

以上海大众联合发展有限公司动力总成分公司所生产的再制造发动机为例,分析了该产品的失效形式、材料性能与再制造之间的关系。结果表明：磨损导致的失效经过再制造切削加工后,配合新的尺寸零件,保证原有的公差配合,可以使磨损失效完全消除,但材料疲劳累积引起的损伤并没有得到修复,经过一次再制造的发动机与新发动机的疲劳寿命有明显差异。     

Determination of the total acid number (TAN) of used gas engine oils by IR and chemometrics applying a combined strategy for variable selection

The most common analyses carried out to assess gas engine oil quality include determination of viscosity, total base number (TBN), and total acid number (TAN). TAN has been considered to be an important indicator of oil quality, specifically in terms of defining oxidation and the extent of acidic contamination of used oils. TAN can be determined by potentiometric titration, and typical values for used oils can reach up to 4 mg KOH/g. A more convenient approach for the determination of TAN is based on infrared (IR) spectral data and multivariate regression models.We developed partial least-squares (PLS) models for the determination of TAN using IR data measured from monograde mineral gas engine oils (SAE 40, medium ash) that have been used in sewer and wood gas engines run with gaseous fuels from a sewage plant and a wood gasification plant, respectively. The final model performance was 0.07 mg KOH/g for the standard error of prediction (SEP). Essential for the development of powerful empirical models was an appropriate variable selection by combining expert knowledge, biPLS or dyn-biPLS, and a genetic algorithm. The optimum complexities of the models (the number of PLS components) and their prediction performances have been estimated by repeated double cross validation (rdCV).     

钼掺杂铜硅钙石的制备及其抗菌性能和细胞相容性研究

含铜生物材料在高浓度铜离子释放时对细菌有优异的抑制作用, 但同时具有细胞毒性; 而在低浓度铜离子释放时虽然具有良好的细胞相容性, 但其抗菌性能低。因此, 开发一种含铜生物材料, 使其能够在高浓度铜离子释放情况下同时具有优异抗菌性能和良好细胞相容性, 具有重要意义。本研究利用钼和铜之间的拮抗作用原理, 采用溶胶-凝胶法制备了钼掺杂铜硅钙石, 并通过细菌平板实验和细胞活力实验评价了材料的抗菌性能和细胞相容性。实验结果显示, 钼掺杂铜硅钙石释放的高浓度铜离子(高于8.87 μg∙mL ^-1)对金黄色葡萄球菌有良好的抑制性能。同时, 由于铜钼离子的拮抗作用能降低高浓度铜离子对细胞的毒性, 钼掺杂铜硅钙石释放的铜离子在9.65 μg∙mL ^-1的高浓度下依然能保证人脐静脉内皮细胞存活率高达90%。因此, 钼掺杂可以作为含铜生物材料降低其细胞毒性的一种有效途径, 为开发低细胞毒性含铜抗菌生物材料提供了新的路径。     

Tribological and Repairing Properties of Combined Nanoparticle SiO2/ZnO

A type of additive-SiO2/ZnO combined nanoparticle were obtained by chemical method. The tribologica land repairing properties as lube additives have been studied by four-ball tester and ring-on-block tribotesters. The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The results show that the additive possesses excellent extreme-pressure( EP), anti-wear(AW) , friction reducion and self-repairing properties. The lubrication and repairing mechanism is inferred that SiO2/ZnO combined nanoparticle is sedimented on the surface of steel, the lower surface film is formed under the high temperature and high pressure. The film possess excellent anti-wear , friction-reducing and repairing properties.