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The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO₂) at high temperature.

In this paper, CeO₂ was self-made and it was chemically modified. The dispersion stability of CeO₂ in lubricating oil was studied. And the wear test of lubricating oil blends added with modified CeO₂ was carried out at high temperature.

The results showed that CeO₂ was successfully modified by oleic acid and stearic acid. The dispersion stability of modified CeO₂ in lubricating oil was improved. Adding modified nano-CeO₂ with the concentration less than 50 ppm into the lubricating oil can improve the wear properties of friction pairs in different extent. With the increase of the amount of CeO₂, the wear properties increased first and then decreased. The lubricating oil blend added with 25 ppm CeO₂ has the best wear properties.

The raw material CeO₂ in this paper is self-made and its shape and size are well controlled. Research on the addition of nano-CeO₂ to the engine low viscosity finished lubricants is lacking. It is of great significance to study the dispersion stability and tribological properties of nano-lubricants under the new background of low viscosity of lubricating oil and close to the real engine working conditions. It has certain significance to promote the development of nano-lubricants for engines.

The purpose of this study is to improve the dispersion of nanoserpentine modified with OA, KH550 and KH550/oleic acid in lubricating oil. The main aims are to analyze the influence of the dispersion and stability of nanoserpentine modified by different modifiers on the friction properties of lubricating oil.

The nanoserpentine particles obtained by ball-milling were modified by silane coupling agent KH550, OA and KH550/OA, respectively. The dispersity and stability of nanoserpentine in base lubricating oil were characterized by the absorbance value method, centrifuge precipitation rate method and static observation method. The MMU-5G screen display friction and wear tester was used to evaluate the tribological properties of C45E4/C45E4 friction pairs in corresponding lubricating oils. The surface morphology of the friction pairs was observed by scanning electron microscopy and energy dispersive spectroscopy.

The results showed that the dispersity and stability of nanoserpentine particles in lubricating oil were best modified by OA, followed by the KH550/OA and finally, the KH550. Nanoserpentine particles modified with oleic acid showed optimum tribological properties as lubricant additives.

This study can improve the dispersion stability of nanoserpentine particles in lubricating oil, increasing the antiwear and antifriction performance of lubricating oil, which has great significance in economic and military aspects.

Improved fuel economy, lower emission and longer durability are the major developing trends of engine oils. Aims to describe further research on the friction coefficient of engine oils.

The lubricating durability D was defined based on definition of three characteristic points P_d, P_S, P_i and three key time lengths T_d, T_s, T_i. Two kinds of engine oils, respectively, belonging to GF‐2 and GF‐3 categories, were selected as samples to compare their lubricating durability.

Test results indicate the GF‐3 oil has much better lubricating durability than GF‐2 oil. With investigation of the topography and chemical composition changes of wear tracks along with the tribotests' time extending, the meanings of three characteristic points were discussed. Analysis indicates much better tribofilm, formed by the synergistic effect of Ca‐containing detergent with MoDTC/ZDTP in GF‐3 oil, is the major factor resulting in GF‐3 oil's longer lubricating durability.

Provides further research on lubricating durability, which is important for engine oil change and maintenance, as well as decreased cost and pollution to the environment, and improved energy conservation.

This study aims to prevent the sharp decline in the load-carrying capacity of lubricating oil film under harsh conditions of abrupt changes in friction interface temperature, which is a major challenge in lubrication technology.

In this paper, we synthesized a series of silver pyrazole methylpyridine complexes containing a high metal concentration and minimal supporting organic ligands (complex 1 [Ag(LMe)]₂(BF₄)₂, complex 2 [Ag(Li-Pr)n](BF4)n and complex 3 [Ag(LMe)(NO₃)]₂). The thermal decompose behavior of as-prepared silver complex was investigated by thermogravimetric analysis and X-ray photoelectron spectrometry (XPS). Four-ball friction testers were used to evaluate the friction and wear properties of lubricating oil in the temperature ranges associated with the operation of modern heavy machinery.

The complex decomposed silver particles at high-temperature, which could fill the pits on the friction surface, change the wear form of the friction pair and reduce the roughness of the friction surface. Reduction in both friction coefficients and wear scar diameters was obtained by adding silver complexes in oil. The lubricating oil, with the additive content of 1.5 Wt.%, has the best tribological performance, moreover, the lubricating performance of the silver complexes in oil were correlated with their concentration and thermal decomposed temperatures, respectively.

As a result, a series of silver pyrazole methylpyridine complexes as oil additives can support friction and wear reduction under abrupt high-temperature conditions are intended to be a controllable backup lubricant additive.

Previous work has suggested that the adhesion between oil and metallic surfaces of an engine could be an important factor in determining crankcase cleanliness. It can be shown that it is only necessary to measure the spreading pressure of an oil on metal in order to get a direct measure of the work of adhesion, Surface tensions of lubrictaing oils vary very little and it can be assumed that the critical film pressure (C.F.P.) obtained with a given apparatus is an acceptable measure of the work of adhesion as well as of the spreading pressure. Oils of similar properties may vary tenfold in their C.F.P's. The addition of additives influences the spreading pressure, the largest increments in C.F.P. being given by dispersant and detergent additives.

This paper aims to study the tribological behavior of the WS2/oil-impregnated porous polyimide (PPI) solid/liquid composite system, in which both PFPE (perfluoropolyether) and SiCH (silahydrocarbons) oils with different hydrocarbon chains were used, respectively. Lubricating mechanism of the composite system was also explored.

The tribological behaviors of the WS2 films against the PPI cylindrical pins before and after immersing oil were evaluated under different loads by a reciprocating-type ball-on-disc tribometer.

The composite system exhibited the low and stable friction coefficient after the running-in stage, and the lubricant oil played a positive effect. It was found that the WS2/PFPE composite system exhibited more excellent lubricating property, although sole SiCH far exceeds PFPE in lubrication. The abnormal phenomenon mainly resulted from the influence of the oil amount. XRD results on the wear track surfaces indicated that PFPE and SiCH oils with different hydrocarbon chains were likely to preferentially adsorb to the edge plane and basal plane of the WS2 crystals, respectively.

In previous studies, liquid lubricants were directly dripped or spin-coated on the solid lubricant surface. Based on its potential advantage in application, the tribological behavior and mechanism of the solid lubricating film/oil-impregnated PPI composite system were investigated in this study.

Today's worries and doubts related to the use of mineral oils increased because of the worldwide interest in environmental issues. This issue has increased the use of vegetable oils as an alternative lubricating oil candidate, environment‐friendly lubricant and their additives. In this study, rapeseed oil (RSO) in different concentrations, 1, 2, 3, 5, 10, 20, 30, 40, 50 (by volume percent), was added to base oil to obtain a lubricating oil candidate. Turkish originated RSO was studied as an additive candidate in this paper. The study of the effect of additives in mineral oils was carried out using a specially designed experimental system to compare lubricating oil candidates and high temperatures using engine journal bearings under statically loaded.

This study aims to evaluate and compare by 100 hours engine bench tests the tribological performances of two types of lubrication oils, which were sulfur-based, boron succinimide-containing antiwear package (NP-3) oil and conventional zinc dialkyldithiophosphate (ZDDP)-containing (R-1) oil.

The tribological performances of the oils were evaluated in three main contexts, including engine tests, physical/chemical changes and surface analysis.

Results showed that NP-3 lubrication oil, which was environment- and catalyst-friendly, can be an alternative lubrication oil with its tribological performance due to similar antiwear characteristics with the ZDDP.

Attempts to develop catalysis- and environment-friendly antiwear additive packages have not presented popular or commonly used ZDDP-free products for the vehicle industry. This study presents tribological characterization of a newly developed ZDDP-free lubricating oil by engine bench tests.

The main role of the gears is to ensure smoothness and noiseless service, required power transmission, precision of processing, necessary degree of efficiency and so on. Lubrication is of significant importance to the protection of gears from tribological processes which cause failure of gears. The aim of this study is to investigate the influence of lubricating oils on the reliability of gears. The experimental investigation of the influence of some industrial oils on the tribological behaviour of gears of machine tools has been carried out at a metalworking factory. The paper presents the following: the classification of industrial oils for gears; the flow‐chart of the choice of the industrial oil for gears; the analysis of the symptoms and the causes of failure to gears; the reliability curves of gears in the function of tribological properties of lubricating oils under the operating conditions of investigation here presented. The reliability of gears was found to be affected by both the type of lubricating oil and the viscosity grade.

This paper aims to overcome the defect that the traditional clustering method is excessively dependent on initial clustering radius and also provide new technical measures for detecting the component content of lubricating oil based on the fuzzy neural system model.

According to the layers model of the fuzzy neural system model for the given sample data pair, the new clustering method can be implemented, and through the fuzzy system model, the detection method for the selected oil samples is given. By applying this method, the composition contents of 30 kinds of oil samples in lubricating oil are checked, and the actual composition contents of oil samples are compared.

Through the detection of 21 mineral elements in 30 oil samples, it can be known that the four mineral elements such as Zn, P, Ca and Mg have largest contribution rate to the lubricating oil, and they can be regarded as the main factors for classification of lubricating oil. The results show that the fuzzy system to be established based on sample data clustering has better performance in detection lubricant component content.

In spite of lots of methods for detecting the component of lubricating oil at the present, there is still no detection of the component of lubricating oil through clustering method based on sample data pair. The new nearest clustering method is proposed in this paper, and it can be more effectively used to detect the content of lubricating oil.