润滑脂中极压抗磨添加剂的研究进展

综述近年来多种类型的极压抗磨添加剂在润滑脂中的研究成果,包括:层片状、球粒状添加剂、微纳尺度的软、硬质点添加剂、微纳尺度的氧化物及其他化合物添加剂、环保型添加剂。总结其抗磨减摩的作用机制,并针对目前研究存在的问题,提出了润滑脂用极压抗磨添加剂研究的方向。     

氯化石蜡基支载型离子液体在极压抗磨剂中的应用

通过分子结构设计,将甲基咪唑引入氯化石蜡(CP)分子链中,合成氯化石蜡基支载型离子液体(CP-mimCl),并通过与基础油复配应用于极压抗磨领域。结果表明,热稳定性方面,最大分解温度CP-mimCl提高24℃,最大分解速率降低3.2%/min,并且表现出分解速率较低的特点;极压抗磨性能方面,不同载荷下CP-mimCl复合混合液的平均磨斑直径较CP复合混合液降低6.8%、7.7%、7.3%,摩擦系数降低36.2%,平均p_B值增大15.7%;SEM结果表明,CP-mimCl复合混合液的磨斑形貌较CP复合混合液更为致密和细腻。     

含硫极压抗磨添加剂在菜籽油中的摩擦学性能研究

利用四球磨损试验机考察了以硫化异丁烯和硫化棉籽油作为菜籽油极压抗磨添加剂时的摩擦学性能,通过测定2种添加剂在不同含量下的最大无卡咬负荷(pB)和不同条件下的磨斑直径(WSD),分析和研究了载荷、摩擦时间、添加剂含量对菜籽油摩擦学性能的影响。试验结果表明:硫化异丁烯可以明显提高菜籽油的承载能力和抗磨性能,硫化棉籽油对提高菜籽油的承载能力和抗磨性能效果不明显,硫化异丁烯在菜籽油中的承载能力和抗磨性能明显优于硫化棉籽油。试验还表明添加剂的含量并非越高越好,否则WSD值将增大。     

Antiwear Action of Mineral Lubricants Modified by Conventional and Uncoventional Additives

The authors of this paper investigated the influence of esters of rapeseed oil fatty acids on the lubricating properties of mineral lubricants containing chosen AW/EP additives. Methyl esters, ethylene glycol esters, and glycerol esters as well as some commercial AW/EP packages based on zinc dialkyldithiophosphate, S–P organic compounds, and sulphurized esters of fatty acids were tested. The tribological tests were carried out with the use of a four-ball machine. Antiwear (AW) properties of tested compositions were determined using their limiting load of wear (G_oz(40)). It appears that the AW action of esters of rapeseed oil fatty acids depends on their structure. The best AW action is shown by compositions of mineral oil lubricants containing AW/EP additives and methyl esters of rapeseed oil fatty acids. The SEM/EDS analysis of the scar surface layer indicated that the presence of these esters in lubricants causes a change in the interaction between AW/EP additives and the metal surface. These observations were confirmed by the XPS surface analysis.     

s极压抗磨添加剂对润滑脂胶体性能的影响

利用离心分油试验机和滚筒试验机分别考察了3种不同的极压抗磨添加剂（T321，TCP和T202）以及其不同添加量、不同的实验温度或时间对锂．钙基润滑脂胶体性能的影响。研究发现，T202对润滑脂的分油影响较大；T321对润滑脂滚筒工作后的滴点有不同程度的提高；TCP对润滑脂的滴点和分油率的影响较小。对上述现象的机制分析可知，3种添加剂分子中的负电性双键、支链及润滑脂皂纤维分子问氢键不同程度影响皂纤维凝胶结构。     

极压抗磨添加剂对润滑脂胶体性能的影响

利用离心分油试验机和滚筒试验机分别考察了3种不同的极压抗磨添加剂(T321,TCP和T202)以及其不同添加量、不同的实验温度或时间对锂-钙基润滑脂胶体性能的影响。研究发现,T202对润滑脂的分油影响较大;T321对润滑脂滚筒工作后的滴点有不同程度的提高;TCP对润滑脂的滴点和分油率的影响较小。对上述现象的机制分析可知,3种添加剂分子中的负电性双键、支链及润滑脂皂纤维分子间氢键不同程度影响皂纤维凝胶结构。     

Antiwear and Extreme Pressure Properties of Nanofluids for Industrial Applications

This study investigates the effect of CuO, TiO₂, Al₂O₃, and multiwalled nanotube (MWNT) nanoparticles at various treat rates on the tribological properties, namely, wear, coefficient of friction (COF), and pressure of seizure (p_oz), of metalworking fluids during lubricating processes in diverse industrial applications. Results are reported based on two methods: wear scar diameter (WSD) and COF by ASTM D5183 and p_oz by the Institute for Sustainable Technologies–National Research Institute (ITEePib) Polish method for testing lubricants under scuffing conditions. Results showed significant improvements with small filler concentrations of nanoparticles. CuO nanofluids showed a diminishment of 86% for WSD at 0.01 wt%, whereas TiO₂ resulted in an increase in p_oz of up to ～250% at 0.05 wt% compared to pure conventional fluid.     

Antiwear Additives for Ester Oils

Esters for lubrication can be classified into two major groups. One is the neopentyl type or the so‐called hindered type. The other is the triglyceride type, which includes vegetable oils. The improvement of the antiwear properties of carboxylic esters by additive technology under boundary lubrication conditions is studied in this paper. Two strategies are considered, based on the structure of the esters. Triglyceride‐type esters are mainly used as rapidly biodegradable fluids. They have carbon‐carbon unsaturated bonds in their molecules, which are susceptible to auto‐oxidation, and this auto‐oxidation has deleterious effects on the antiwear properties. A synergistic effect of antioxidants and antiwear additives on wear reduction was observed. The mechanism is discussed and practical solutions proposed. Neopentyl‐type esters have thermal and oxidative stability. For these oils, the antiwear properties depend on the polarity of the additive and base oil. The effect of molecular structure on the antiwear properties is discussed. Computer simulation is used to understand the mechanism of action. Examples of molecular design of antiwear additives for neopentyl‐type esters are also proposed.     

Molecular Design of Environmentally Adapted Lubricants: Antiwear Additives Derived from Natural Amino Acids

Novel environmentally adapted lubricant additives were synthesized from cystine (Cys ₂ ), an essential amino acid obtained from natural sources. The structural feature of cystine is a dimeric amino acid with a central disulfide bond. The carboxyl groups in Cys ₂ were converted to corresponding esters by reaction with long-chain alcohols. The resultant diesters were soluble in poly-alpha-olefin (PAO) and ester-type synthetic oils. The structural features of the new additives include multifunctional groups on the same molecule, such as disulfide as a tribologically active moiety and polar functional groups as anchors to friction surfaces. The additives consist of hydrogen, carbon, nitrogen, oxygen, and sulfur; they are free of phosphorus, chlorine, and metals. The tribological properties of the additives in a solution of synthetic oil were evaluated by performing laboratory tribotests under boundary conditions. The Cys ₂ -derived additives exhibited comparable antiwear properties to the conventional additive zinc dialkyldithiophosphate (ZnDTP). The additives showed good antiwear properties even at low concentrations of sulfur (160 ppm) in synthetic hydrocarbons such as PAOs. A high concentration of sulfur (640 ppm) was required to obtain an optimized antiwear performance of the synthetic esters as a base oil. The new additives reduced the friction coefficient of PAOs and synthetic esters. A saturated ester of Cys ₂ reduced the friction of PAOs and synthetic esters up to oil temperatures of 150°C. The lubrication mechanism was discussed with respect to the role of functional groups in the additive molecule. The use of amino acids as versatile building blocks for the synthesis of environmentally adapted additives was also pointed out.     

二烷基二硫代氨基甲酸钼的极压抗磨性能

采用四球机考察了二烷基二硫代氨基甲酸钼（MoDTC）在150SN基础油中的极压抗磨性能,及其与二烷基二硫代磷酸锌（ZnDDP）、亚甲基双二丁基二硫代氨基甲酸酯（双DTC）添加剂的抗磨协同效应,并对MoDTC抗磨作用机制进行了分析研究。结果表明,MoDTC在基础油具有良好的极压抗磨性能,与ZnDDP、双DTC表现出了良好的抗磨协同效应,特别是与ZnDDP表现出了非常好的抗磨协同效应,这可能是ZnDDP有助于MoDTC在摩擦表面形成更多的MoS2。     

二烷基二硫代磷酸盐的制备及抗磨性能

本文制备了四种新型的水溶性二烷基二硫代磷酸盐极压抗磨剂,并测定了其抗磨性能。结果表明,带支链及环状结构的添加剂极压抗磨性能最好。由斯本－６０所制得的二烷基二硫代磷酸盐极压抗磨剂的１％水溶液的ＰＢ值达７４４Ｎ,Ｄ１５＾３９２为０．３４ｍｍ。     

二烷基二硫代磷酸钕作为锂基脂添加剂的极压抗磨作用机理

合成了二正十六烷基二硫代磷酸阴离子与稀土离子（Ｎｄ＾３＋）的中性络合物，考察了具有类似配体结构的稀土和过渡金属（Ｚｎ）络合物对锂基脂摩擦学性能的影响，通过Ｘ光光电子能谱对添加剂的作用机理进行了研究。     

Deposit-Forming Tendencies of High-Temperature Lubricants

A laboratory unit is described with a method for determining the deposit-forming tendencies and oxidation stabilities of lubricants in thin films. The test oil is passed over a spinning aluminum disk heated to temperatures of 500–650 F, which provides a dynamic oil film of about 0.0003 inch thickness. Oxidation stability is determined by measurement of the oxygen consumed. The deposits on the disk are estimated visually. The test can be used for comparative evaluation of base fluids and inhibited fluids.

Test results on a series of high-temperature lubricants approximate deposition data obtained in jet engine tests and in CRC high-temperature bearing tests.     

Antiwear Additives in Neopentyl Ester Oils

A variety of organophosphorus and other selected compounds were studied as antiwear additives for neopentyl polyol ester lubricants on 440C stainless steel rubbing surfaces using a four-ball wear test machine. Their effectiveness as additives was compared with that of tricresyl phosphate. Although 440C steel is relatively unreactive, it was possible to improve strikingly its wear and friction characteristics with organophosphorus additives. Some of the best results were obtained with acid phosphates. Alkyl chain length also appeared to be a significant factor. It was demonstrated that small concentrations of extraneous acidic substances are responsible for the antiwear action of phosphites at high load and that larger amounts of such acidic materials are needed as the load increases. Experiments involving addition of amines to neutralize formulations containing an acid phosphate confirmed that free acids promote antiwear action at the higher loads. Vinyl stearate and selected compounds containing chlorine or sulfur proved ineffective as additives for 440C steel in the antiwear region.     

黄原酸酯类杂环化合物的极压抗磨性定量构效关系研究

以从头计算Hartree-Fock分子轨道法计算三类(2-烷基黄原酸酯基乙酰氨基吡啶、2-烷基黄原酸酯基乙酰氨基苯并噻唑、2-烷基黄原酸酯基乙酰氨基噻唑)黄原酸酯基杂环润滑油添加剂的量子化学结构参数,通过多元线性回归分析分别研究这些分子的磨斑直径、最大无卡咬负荷与量子化学结构参数之间的关系,建立具有良好拟合效果和预测能...     

环境友好润滑剂及其添加剂的摩擦学研究现状

综述了环境友好润滑剂及其添加剂的定义、分类及应用,介绍了生物降解润滑剂的定义及其试验方法与分类;简要介绍了生态毒性和基础的氧化稳定性试验方法;概述了国外环境友好润滑剂的发展状况,指出了国内开展相关研究工作的紧迫性。     

Fluoride Solid Lubricants for Extreme Temperatures and Corrosive Environments

Fluorides of the alkali metals and the alkaline earth metals have an interesting combination of properties that make them promising candidates as solid lubricant materials for use at high temperatures and in corrosive environments. They are chemically inert in strong oxidizing or reducing environments; they are relatively soft and nonabrasive; and some of them, such as CaF₂, have planes of perfect cleavage in their crystal structure suggesting low-shear strength and good friction properties. Thin, fused fluoride coatings (0.001 inch) were applied to nickel-chromium alloys by spraying water slurries of the fluorides on the bearing surface, drying it, then firing it in a hydrogen atmosphere. Coatings of CaF₂-LiF mixtures and of CaF₂-BaF₂ mixtures were effective as solid lubricants in hydrogen to 1500 F and in air to 1200 F. The CaF₂-BaF₂ coatings were effective solid lubricants in liquid sodium at 1000 F and a sliding velocity of 2000 ft/min.     

Antagonistic Interaction of Antiwear Additives and Carbon Black

It is well known that the presence of soot in engine oils can lead to an increase in wear of engine parts. This is a growing problem as soot levels in diesel engine oils are rising due to a combination of extended drain intervals and the various methods employed to reduce NO _x formation such as retarded ignition and exhaust gas recirculation. Several different mechanisms have been proposed by which soot might lead to an increase in wear in mixed lubrication conditions, of which the most widely favoured is abrasion by soot, either of the rubbing metallic parts in engines or of the antiwear additive films formed on rubbing metal surfaces. In this study it is shown that the combination of mixed alkyl ZDDP and carbon black (used as soot surrogate) is strongly antagonistic in terms of wear. In a lubricant containing carbon black, the presence of ZDDP leads to considerably more wear than if ZDDP is left out. A similar, though less severe antagonism is also seen with primary ZDDP and other antiwear and EP additives. By varying the lubricant film thickness it is shown that the effect of carbon black in ZDDP-containing oils is to promote wear up to quite thick hydrodynamic film conditions, approaching the secondary carbon black particle size. It is proposed that the antagonistic wear effect results from a corrosion-abrasive mechanism in which the reaction film formed by antiwear additive and rubbing metal surface is very rapidly and continually abraded by carbon black. At most carbon black concentrations, wear rate then becomes controlled by the rate of initial antiwear additive film formation, which for secondary ZDDP is very rapid, rather than by the kinetics of the abrasive process. From this understanding, strategies for reducing the impact of engine soot on wear can be deduced.     

Oil-Soluble Fluorinated Compounds as Antiwear and Antifriction Additives

Many studies have been published on the use of solid fluorinated compounds as lubricants and lubricant additives, but much less has been done with oil-soluble fluorinated additives.

This paper describes a study of fluorinated telomers, especially fatty acids and their amine salts, for boundary lubrication (antiwear conditions). The antiwear effectiveness of these fluorinated compounds is compared with a commercial additive, zinc di-n-butyl dithiophosphate (ZDTP).

Modern analytical tools are used to study surface layers (XPS, automatic wetting balance), and wear particles (IR) to determine their antiwear mechanism. Special attention is given to fluorinated reaction film formation.