Development of Metal Cladding Additives for Agricultural Machinery Friction Unit Parts

The choice of materials for the formulation of the metal cladding additive has been theoretically substantiated. A process has been developed and a copper-containing lubricant composition has been synthesized. It is shown that the use of a metal cladding additive having antifriction and antiwear properties reduces 2.9 times the part wear rate. The effect of the additive on the anticorrosion properties and thermal-oxidative stability of the base oil has been studied.

Investigation of tribological characteristics of lubricant grease based on Solidoil and urea resin thickener

The results of laboratory investigation of the tribological characteristics of a new grease based on Solidol, a polyurea thickener providing an increase in the dropping point to 118 °C, and a complex of additives are presented. It has been established that the proposed lubricant is efficient in a wider temperature range, provides higher antiwear properties for tribocoupling parts and considerably reduces friction losses during boundary lubrication in comparison with the original grease Solidol. The developed composition of the lubricant grease is supposed to be used when operating road construction machines in the tropical conditions of Vietnam.

Development of methods for evaluation of lubrication properties of hydraulic aviation oils

A method for evaluation of the lubricating and rheological properties of hydraulic oils in tribological contacts has been developed, which consists in online studying samples of commercial batches of oils on a software and hardware complex with visual evaluation of the kinetics of changes in the main tribological indicators of friction contact. Using a roller analogy, the operation of gears in the conditions of rolling with 30% sliding is simulated. Samples of AMG-10 oil from two producers are analyzed. It is established that with increasing temperature of lubricant for Sample 2 (“Kvalitet-Avia” AMG-10), a long-term restoration of protective boundary films of oil is observed and the period of their formation increases by 2.5 times, causing the implementation of a semidry mode of lubrication at start-up. The total thickness of the lubricating layer is 1.27 times less as compared with Sample 1 ("Bora B" AMG-10 oil), regardless of the lubricant temperature. Also, the rheological properties of the oils have been determined. Sample 1 exhibits low shear stresses at the level of 9.4 MPa and high effective viscosity, 4249 and 5039 Pa·s, at a volumetric oil temperature of 20 and 100 ºС, respectively. For Sample 2, with increasing oil temperature to 100 ºC shear stress increases by 1.15 times and the effective viscosity in contact decreases by 1.53 times. Additives present in Sample 1 are characterized by more effective antiwear properties and thus increase the wear resistance of contact surfaces in the conditions of rolling with sliding thanks to strengthening of the surface metal layers during operation, while Sample 2 undergoes strengthening-softening processes which reduce the wear resistance of friction pairs

An experimental study on the effect of concentration of green nanoadditives on the tribological properties of the biolubricants

The paper aims to introduce a sustainable solution in the field of lubrication science. A green nano additive, hexagonal boron nitride (h-BN) is mixed with two biofriendly natural oils (avocado oil and hazelnut oil) and the tribological properties of the nanolubricants are evaluated on a four-ball tribotester. The nanoparticles are less than 100 nm in diameter and are added in varying concentrations of 0-1 wt.%. The tribological properties are evaluated as per ASTM D4172 and the stability of the nanoparticles is measured for a period of 24 hours using a double beam spectrophotometer. The UV spectroscopy results indicate the nanoparticles are stable after the sonication process and sediment very less after 24 hours. The antiwear properties of both natural oil improve with the increase in the concentration of h-BN nanoparticles. The maximum improvement in the wear properties is observed at 1 wt.% and is equal to 19.5% and 36.55% for avocado oil and hazelnut oil respectively. The improvement in the antiwear properties are ascribed to the different nanolubrication mechanisms: tribofilm formation, non-direct contact phenomenon, and entrapment of nanoparticles between wear agglomerates.

Moringa oil with pristine and fluorinated carbon nanofibers as additives for lubrication

This paper focuses on the influence of local moringa oil on the performances of lubricants formed from blend of dodecane and pristine or fluorinated carbon nanofibers at ambient temperature. The friction experiments have been evaluated using a reciprocating ball on plane tribometer. Moringa oil is designed to be used as a bio-additives in lubricant formulations. First, the addition of small amounts of moringa oil in dodecance allowed a reduction about 50% of the base oil friction performances. In a second part, a comparative study investigates the friction properties of their blends with pristine carbon nanofibers (CNFs) and fluorinated ones (CF0.85) which are intended to be used as solid lubricant additives. An adsorption effect of fatty acid molecules is showed with CNFs particles unlike CF0.85. Whatever was the percentage of moringa oil added, the more promising results were obtained with CF0.85. Physicochemical characterizations of the tribofilms evidence the good antiwear properties of the lubricants.

Moringa and Graphite as Additives to Conventional Petroleum-Based Lubricants

Many researches are focused on the tribological performances of pure vegetable oil in order to replace the conventional mineral engine oils. This work investigates the influence of local moringa oil (noted VO) on the performances of lubricants formed from a blend of dodecane and graphite particles at ambient temperature. In a first part, a reduction of about 50% of friction properties of dodecane is observed when adding small amounts of moringa oil (VO), which is intended to be used as a bio-base performance additive in lubricant formulations. The friction properties of their blends with graphite, generally employed as solid lubricant additive, showed an adsorption effect of fatty acid molecules. The more promising results were obtained for the blend containing 2 w% of VO. Physicochemical characterizations of the tribofilms evidence the good antiwear properties of the lubricant.

Development and research of metal-cladding additive to lubricants

The article indicates that one of the directions of increasing the wear resistance of rubbing parts of machines and equipment, reducing friction losses and temperatures in the friction zone is the use of special metal-plating additives to lubricants. The Engineering Center of the Timiryazev Academy has developed an experimental metal-cladding additive under the code name “MP-21” based on a mixture of fatty acids (oleic, stearic, linoleic) and plastic metal salts of the same fatty acids. The tribotechnical properties of lubricating compositions with various additives in recommended concentrations were investigated on a modernized Timken-mashine friction machine in a steady state using samples from real rolling bearing assemblies. It has been established that the developed metal-cladding additive “MP-21”, along with the additive Renom Engine, provides maximum antiwear properties and allows to reduce the wear of rubbing samples in comparison with other investigated additives from 30% to several.

Study of the reactions of interaction of alkylxanthogenates with chlorine derivatives of glycerin and study of lubricating properties of synthesized compounds

The reactions of 1-chloropropanediol and 1-chloro-3-alkylcarboxymethyl-propanol-2 with alkylxanthogenates have been studied; mixtures of acyclic, cyclic xanthates and tritiocarbonates are formed. The dependence of the direction of the reaction and, accordingly, the yields of the synthesized compounds on the ratio of reagents and conditions of the experiments was revealed. The evidence that both acyclic and cyclic compounds are formed in these reactions are spectral (IR) and physicochemical (n_D^20, d_4^20, MRD, elemental composition). The obtained compounds were investigated as extreme pressure additives to lubricating oils, their effectiveness as extreme pressure additives was revealed. The high extreme pressure properties of the synthesized compounds are explained by the fact that their molecules contain polar thiocarbonyl (C=S), 1 sulfide (CS) sulfur in xanthates and 2 sulfide sulfur in tritiocarbonates, which are easily adsorbed on the metal surface, forming at high temperatures, protective layer consisting of metal sulfides. Due to the fact that all the obtained compounds are high-sulfur, they do not have antiwear properties, that is, they cause corrosive wear, in order to improve the corrosive properties of oils, the authors have compiled compositions using the antiwear and antioxidant additives DF-11.

SILICONE MAGNETIC NANOFLUIDS ADAPTED FOR THE CONDITIONS OF BOUNDARY FRICTION

Известные в настоящее время магнитные смазочные наножидкости имеют недостаточно хорошие триботехнические характеристики при эксплуатации в режиме граничного трения. Предложен способ адаптации для граничного трения магнитных силоксановых наножидкостей, путем модификации их состава химически активными антифрикционными, противоизносными и противозадирными присадками. Создан ряд смазочных композиций магнитных наножидкости на основе полиэтилсилоксана ПЭС-5. Поведенные экспериментальные исследования показали, что наиболее значительное улучшение антифрикционных и противоизносных свойств наножидкостей достигается при введении в их структуру хлорсодержащих присадок Совол и 3Н2ТЭ. Добавление в наножидкость антиокислительной присадки ДФ-11, фторсодержащей присадки ЭО-1, металлоплакирующего соединения МКФ-18 не привело к значимому улучшению антифрикционных свойств. Установлено, что магнитные наножидкости с модифицирующими присадками, по трибосвойствам сопоставимы с традиционными немагнитными жидкими смазочными материалами и превосходят пластичные смазки на основе полиэтилсилоксана. Разработанные композиции на основе силоксановых наножидкостей, будут востребованы для смазывания подшипников качения и скольжения, зубчатых передач, контактных уплотнений, которые функционируют при низких и повышенных температурах в газовой среде или в условиях вакуума. Наиболее успешно они могут применяться в вакуумной и космической технике, для магнитных трибоузлов, где возможна только однократная заправка ограниченным объемом смазочного материала. Currently known magnetic lubricant nanofluids have insufficiently good tribological characteristics when operating in the boundary friction mode. An adaptation method is proposed for the boundary friction of magnetic siloxane nanofluids by modifying their composition with chemically active antifriction, antiwear and extreme pressure additives. A number of lubricating compositions of magnetic nanofluids based on polyethylsiloxane PES-5 have been created. Conducted experimental studies have shown that the most significant improvement in the antifriction and antiwear properties of nanofluids is achieved with the introduction of Sovol and 3N2TE chlorine additives into their structure. Adding to the nanofluid the antioxidant additive DF-11, the fluorine-containing additive EO-1, the metal-plating compound MKF-18 did not lead to a significant improvement in the antifriction properties. It has been established that magnetic nanofluids with modifying additives are comparable in tribological properties with traditional non-magnetic liquid lubricants and are superior to plastic lubricants based on polyethylsiloxane. The developed compositions based on siloxane nanofluids will be in demand for lubrication of rolling and sliding bearings, gears, contact seals, which operate at low and elevated temperatures in a gas environment or in a vacuum. Most successfully, they can be used in vacuum and space technology, for magnetic frictional units, where only one refueling with a limited amount of lubricant is possible.

Nanolubricant additives: A review

Using nanoadditives in lubricants is one of the most effective ways to control friction and wear, which is of great significance for energy conservation, emission reduction, and environmental protection. With the scientific and technological development, great advances have been made in nanolubricant additives in the scientific research and industrial applications. This review summarizes the categories of nanolubricant additives and illustrates the tribological properties of these additives. Based on the component elements of nanomaterials, nanolubricant additives can be divided into three types: nanometal-based, nanocarbon-based, and nanocomposite-based additives. The dispersion stabilities of additives in lubricants are also discussed in the review systematically. Various affecting factors and effective dispersion methods have been investigated in detail. Moreover, the review summarizes the lubrication mechanisms of nanolubricant additives including tribofilm formation, micro-bearing effect, self-repair performance, and synergistic effect. In addition, the challenges and prospects of nanolubricant additives are proposed, which guides the design and synthesis of novel additives with significant lubrication and antiwear properties in the future.