不同极性基团表面修饰剂对纳米氟化镧摩擦学性能的影响

以不同极性基团的十八酸二乙醇胺、双β羟乙基十八胺及二辛基二硫代磷酸二乙醇胺为表面修饰剂,在醇-水体系中制备了3种纳米氟化镧粒子,通过透射电镜（TEM）及热重仪（TG）研究了纳米氟化镧粒子的形貌及表面修饰情况,采用离心沉降法考察了纳米粒子在基础油中的分散稳定性,用四球机考察了它们的摩擦学性能,最后采用扫描电子显微镜（SEM）和俄歇电子能谱仪（AES）分析了磨痕表面。结果表明：二烷基二硫代磷酸胺盐修饰的纳米粒子粒径更小,更均匀。表面修饰剂极性基团同无机纳米核强的化学作用且极性基团具有多长侧链更有利于纳米粒子在基础油中分散稳定。含牺牲性润滑元素硫和磷的表面修饰剂纳米粒子因极压膜的生成而有更好的极压抗磨性能。表面修饰剂的亲油链越长越有利于发挥纳米粒子的减摩作用。     

油酸修饰纳米氟化镧的摩擦学性能

以油酸为修饰剂制备表面改性的氟化镧纳米粒子,在环块式摩擦磨损试验机上考察氟化镧纳米粒子在150N基础油中的摩擦学性能,借助透射电镜(TEM)、金相显微镜及X射线衍射仪(XRD),分别对磨损试样的表面形貌和元素成分进行观察和分析,探讨表面修饰氟化镧纳米添加剂的抗磨减摩机制.结果表明:油酸修饰的氟化镧纳米粒子在150N基础油中减摩抗磨效果明显,与纯基础油润滑相比,在250 N压力和450 r/min转速条件下,质量分数2％的氟化镧纳米粒子在稳定磨损阶段可使45#钢试样摩擦因数降低40％,总失重降低43.75％.EDX分析表明,氟化镧纳米粒子在摩擦过程中在磨损表面生成了自修复膜.     

油溶性氟化镧纳米棒的制备及其摩擦学性能研究

利用超声波辅助处理,在乙醇-水体系中,以二辛基二硫代磷酸双(β-)羟乙基十八胺盐为表面修饰剂制备了表面修饰氟化镧纳米棒,通过相转移法制得油溶性纳米氟化镧添加剂.通过X射线衍射仪(XRD)、透射电镜(TEM)及热重仪(TG)表征了表面修饰氟化镧纳米棒的结构及形貌,利用离心沉降法和升温法结合研究了添加剂中纳米氟化镧在500SN基础油中的分散稳定性和高温稳定性,利用四球机考察了纳米氟化镧的摩擦学性能,并通过SEM和AES分析了钢球磨斑表面.结果表明:氟化镧纳米棒直径在4～7 nm之间,长度为20～30 nm;氟化镧纳米棒在500SN基础油中具有良好的分散稳定性,并可使基础油的最大无卡咬负荷值增加了109.61%,磨斑直径降低39.13%;AES结果表明,氟化镧沉积在磨斑表面形成一层复合膜,并且渗透入磨斑的亚表面,共同提高基础油的摩擦学性能.     

油溶性钙掺杂氟化镧纳米粒子的制备及其摩擦性能研究

在乙醇-水体系中,以二辛基二硫代磷酸双(β-)羟乙基十八胺盐为表面修饰剂,以氯化钙和氯化镧为原料,制备了油溶性钙掺杂氟化镧纳米粒子和氟化镧与氟化钙混合体纳米粒子.通过X射线衍射仪(XRD)、透射电镜(TEM)、热重仪(TG)及傅立叶红外(FTIR)表征了表面修饰纳米粒子的结构及形貌,利用离心沉降法和升温法结合研究了添加剂中纳米粒子在500SN基础油中的分散稳定性和高温稳定性,利用四球机考察了纳米粒子的摩擦学性能,并通过SEM分析了钢球磨斑表面.结果表明:La、Ca摩尔比为1∶1时,纳米粒子为氟化镧晶体和氟化钙晶体的混合物;La、Ca摩尔比为1∶2时,其结构为掺杂体;2种纳米粒子形貌和粒径一样,平均粒径在10 nm左右;在500SN基础油中具有良好的分散稳定性;掺杂体纳米粒子的摩擦学性能高于混合体纳米粒子,含掺杂体纳米粒子油样的最大无卡咬负荷值比基础油提高了1.15倍,磨斑直径比基础油降低了42.6%.     

油酸修饰纳米粒子的摩擦学性能比较

利用化学法合成了表面为油酸所修饰的PbS、PbO和ZnS纳米粒子,由于无机纳米粒子表面有一层由油酸组成的长链有机化合物,使得所修饰的PbS、PbO和ZnS纳米粒子在基础油中有良好的分散性,能够作为润滑油添加剂。用四球摩擦磨损试验机分别考察了它们作为润滑油添加剂的摩擦学行为,结果表明,无机纳米核的化学组成、大小,以及摩擦过程中所形成边界润滑膜的成膜机制对油酸修饰纳米粒子作为润滑油添加剂的摩擦学性能影响不大,所合成的油酸修饰PbS、PbO和ZnS纳米粒子作为润滑油添加剂都能够明显提高基础油的减摩抗磨性能。     

修饰剂对PbO纳米粒子摩擦学性能的影响

用化学方法分别合成了表面为二-十六烷基二硫代磷酸（DDP）单分子层修饰的PbO纳米粒子和油酸（OA）单分子层修饰的PbO纳米粒子,用透射电子显微镜（TEM）表征了它们的形貌,并用四球摩擦磨损试验机比较了它们作为润滑油添加剂的摩擦学行为.结果表明,两种PbO纳米粒子的平均粒径都约为5 nm,且都能起到良好的抗磨效果,由于修饰剂的影响,油酸修饰PbO纳米粒子作为润滑油添加剂能够明显降低摩擦因数,而DDP修饰PbO纳米粒子却不能降低基础油的摩擦因数.     

油溶性纳米TiO2粒子的制备及其结构表征

利用液相沉积法制备十二烷基三甲氧基硅烷(DTMS)修饰的油溶性纳米TiO2粒子,研究修饰温度、修饰时间和修饰剂用量对TiO2油溶性以及在基础油中分散稳定性的影响,采用红外光谱仪(FT-IR)、透射电子显微镜(TEM)进行了结构表征.结果表明:修饰温度为40℃、修饰时间为12 h、修饰剂与TiO2比例为2∶1(摩尔比)时,所得粒子具有最佳亲油化度和分散稳定性;纳米TiO2粒子表面的DTMS修饰膜,可有效控制粒径的过度增长,避免粒子间的团聚,增强了纳米TiO2在基础油中的分散稳定性.     

W/O微乳液法制备表面修饰纳米氟化镧润滑油添加剂

采用聚异丁烯丁二酰亚胺T152/S-80复合表面活性剂(w(Span80)∶w(Tween20)=2∶3(质量比))/异丁醇/500SN基础油/氟化铵水溶液W/O微乳液体系构建微反应器,通过原位表面修饰制备了含纳米LaF3粒子的液体润滑油添加剂,同时,采用洗涤法制备了干粉纳米LaF3。采用X-射线衍射仪(XRD)和透射电镜(TEM)分析了纳米LaF3粒子的结构和形貌。分别将液体添加剂和干粉加入基础油中,采用离心沉降法考察了不同后续分离方法得到的纳米粒子在基础油中的分散稳定性,用四球机考察了它们的摩擦学性能,最后采用扫描电子显微镜(SEM)观察了磨斑表面形貌。结果表明:所构建的微反应器制备的颗粒状纳米LaF3平均粒径在10~15 nm之间;纳米粒子在基础油中的分散稳定性对其摩擦学性能影响很大,液体添加剂中的纳米粒子在基础油中的分散稳定性和摩擦学性能大大高于干粉粒子;液体添加剂中的表面活性剂不仅有利于纳米粒子在基础油中的稳定分散而且有减摩作用。     

油酸修饰PbS纳米粒子的摩擦学性能剖析

合成了基础油中分散性良好的油酸（OA）修饰PbS纳米粒子，并用四球摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学行为，结果表明，OA修饰PbS纳米粒子在较低的添加浓度下就具有良好的减摩和抗磨效果，未修饰PbS纳米粒子作为润滑油添加剂时有一定的减磨作用，而修饰剂油酸则具有一定的抗磨性能。     

纳米ZnS粒子作为润滑油添加剂摩擦学性能研究

采用均匀沉淀法制备了硬脂酸修饰的纳米ZnS粒子,用四球摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学性能,并用扫描电子显微镜和X射线光电子能谱仪对磨斑进行了表面分析.结果表明:在一定添加量范围内,硬脂酸修饰的纳米ZnS粒子可明显改善基础油的摩擦学性能;在摩擦过程中,纳米ZnS粒子在摩擦表面的沉积和通过摩擦化学反应生成的化学反应膜,显著提高了基础油的抗磨减摩性能.     

Adsorption characteristics and lubricating performance of coolant components in cold rolling of aluminum

In the cold rolling of aluminum foil, coolants made with nonaromatic base oils provide poor lubricity compared with coolants made with conventional base oils. But there is no clear difference in lubricity between nonaromatic and conventional base oils in the case of the rolling of aluminum sheet. In evaluations of the adsorption activity of model base oil components, alkylbenzene with a longer alkyl chain shows the potential to enhance the adsorption activity of alcohol onto the nascent aluminum surface. In experimental rolling, furthermore, the lubrication performance of coolants using nonaromatic base oils can be improved with the addition of dodecylbenzene. The addition of 10 mass% of dodecylbenzene into a nonaromatic coolant is sufficient for practical lubrication performance in the cold rolling of aluminum.     

Concept of molecular design towards additive technology for advanced lubricants

A simple model to develop novel friction modifiers and anti‐wear agents for synthetic oils was studied. Our attention was focused on the construction of additive molecules to meet the requirement for synthetic oils, which possess a different polarity and solvency from mineral oils. The relation between the molecular structure of additives and their tribological properties were elucidated prior to the preparation of the substance and estimation of its tribological properties. Computer‐assisted chemistry was partly applied to predict the properties of the designed molecules. The adsorptive activity of the conventional fatty acids is insufficient to reduce friction when they were dissolved in polar synthetic oils such as polyethers. Introduction of another carboxyl group into the fatty acid, especially at the carbon atom next to the original carboxyl group, makes the molecule polar; resulting in friction modifiers for polyethers. Conversion of the carboxyl groups into trimethylsilyl esters provides soluble friction modifiers for poly(dimethylsilicone)‐type synthetic oils. A unique lubrication mechanism based on in situ regeneration of the original molecule was proposed for synthetic oils with poor solvency. Importance of adsorptive activity of additive molecule was also pointed out in phosphate‐type anti‐wear additives for polar synthetic oils. We found that both the polarity of additives and that of base oils have to be taken into account in lubricant design. Too much adsorption activity of the molecule caused corrosive wear. Hydrolytic stable compounds reduces corrosive wear to a considerable extent. Introduction of a hydroxyl group into the alkyl moiety of the phosphate ester provides polar molecule with low acidity. The additives reduce wear in synthetic esters even at low concentrations of phosphorus. The lubrication mechanism was also discussed; the novel additives provide a thick boundary film composed of iron phosphate on rubbing surfaces. Moreover, an acceleration of the kinetics of the film formation by the hydroxyl group was observed. Copyright © 2007 John Wiley & Sons, Ltd.     

几种羟基脂肪酸在菜籽油中的润滑行为研究

利用四球摩擦磨损试验机,考察了实验室合成的几种羟基脂肪酸在菜籽油中的减摩抗磨和极压性能。试验结果表明：这些含氧添加剂具有一定的减摩抗磨能力,但对菜籽油的极压性能的没有影响。双羟基脂肪酸比单羟基脂肪酸的减摩抗磨效果更为明显;烷基链较长的羟基甘二酸比羟基十八酸的减摩抗磨性能略好。     

Phosphate esters with a complex alkyl‐aryl structure considered as tribological fluids

This paper presents results of reserch carried out to produce synthetic ester oils with adequate tribological properties, which could also act as antiwear additives. By varying the molar relationship between aliphatic alcohols of variable chain length and a special alcohol with complex alkyl‐aryl structure, namely 2‐[(o‐sec‐butyl)phenoxy]ethanol, two series of new phosphate esters have been synthesised. The influence of the aryl content and the effect of the length of the aliphatic chain on the characteristics of these esters as base oils, and on their qualities as antiwear additives, have been investigated.     

表面修饰氟化镧纳米粒子的制备及摩擦学性能研究

采用化学沉淀法以氟化物(NaF)和稀土氯化盐(LaCl3)为原料制备LaF3纳米粒子;采用透射显微镜(TEM)和X射线衍射仪(XRD)对纳米粒子的结构和形貌进行表征及分析;用硅烷偶联剂KH550对其表面改性,在高速高温摩擦磨损试验机上研究改性后的LaF3纳米粒子添加到纯基础油中的摩擦学性能,分析其抗磨减摩机制。结果表明,LaF3纳米粒子添加到润滑油中能提高其摩擦学性能,起到减摩耐磨效果;摩擦过程中LaF3纳米粒子渗透到试件中,起到修复作用。     

The behaviour of friction modifiers under boundary and mixed EHD conditions

The behaviour of a range of model and commercial friction modifiers (FMs) has been evaluated under elastohydrodynamic (EHD) and boundary lubrication conditions. Using a series of long‐chain carboxylic acids, it has been shown that measured boundary friction coefficients (BFCs) decrease with increasing chain length, unsaturation level, temperature, and concentration. Base oil polarity was found to have no effect under these conditions. Commercial oleate esters in synthetic base fluids gave lower BFCs than nitrogen‐containing compounds under the same conditions. This difference was observed over a range of concentrations and temperatures. The friction performance of formulated oils under mixed and full‐film EHD conditions was found to be dependent on FM, base oil, and detergent type. Under boundary conditions, friction was found to vary with FM type, but the effect of changing the base oil and the detergent system was negligible.     

添加油酸修饰的纳米Fe3 O4粒子润滑油的摩擦学性能研究

利用化学共沉淀法制备了平均粒径为10nm、油酸表面修饰的Fe3O4粒子，并对其作为润滑油添加剂的摩擦学性能进行了研究。试验结果表明，添加油酸修饰的纳米Fe3O4粒子的润滑油表现出了较好的抗磨减摩性能，但是，纳米粒子的添加量有一最佳值。与基础油相比，添加纳米Fe3O4粒子润滑油的摩擦因数最大降低了26％，磨损量降低了28％。在摩擦磨损过程中，添加纳米Fe3O4粒子润滑油的摩擦力矩的变化表现出了时间效应。添加纳米Fe3O4粒子润滑油摩擦磨损后的磨痕表面比基础油摩擦磨损后的磨痕表面光滑，可以推测，纳米Fe3O4粒子对摩擦表面的抛光作用提高了润滑油的摩擦学性能。     

Test procedure for rapid assessment of frictional properties of engine oils at elevated temperatures

A fifteen-minute test sequence has been developed for screening and ranking base oils and friction modifiers. The tests are run on a high-frequency friction machine developed at the authors' company and based on the Mills-Cameron design. The procedure can distinguish clearly and repeatably between the behaviour of different friction modifiers and with a degree of discrimination which is better than has been achieved in engine mechanical loss tests     

纳米二硫化钼作为润滑油添加剂的摩擦学性能研究

研究纳米二硫化钼作为润滑油添加剂的摩擦学性能。以不同的表面活性剂和不同的超声波分散时间制备纳米二硫化钼润滑油,考察表面活性剂和超声波分散时间对纳米二硫化钼分散稳定性的影响。采用四球机和描电镜考察纳米二硫化钼在润滑油中的摩擦学性能。结果表明,2%油酸表面活性剂和超声波分散30 min可有效提高纳米二硫化钼在润滑油中的分散稳定性,纳米二硫化钼在润滑油中具有良好的抗磨性能、减摩性能,特别是0.01%二硫化钼在润滑油中的抗磨性能和高负荷下的减磨性能更为突出。