Anti-wear additive

Abstract

FIELD: petrochemistry.SUBSTANCE: invention can be used for lubricating oils to improve their tribotechnical properties when used in marine equipment. An anti-wear additive is proposed, comprising micelles based on molecules of a solid plastic lubricant of iron oxide Fe3O4 doped with cobalt Co (II), with surrounding molecules of oleic acid. The anti-wear additive additionally contains fullerene nanomodifiers in the form of polyhedral carbon clusters C60 and C70 and a powdered metal filler in the form of a copper nanopowder.EFFECT: improvement of tribotechnical characteristics of lubricating oils.1 cl, 1 dwg, 1 tbl

Description

[0001] The invention relates to mechanical engineering, in particular to anti-wear additives for lubricating oils to improve their tribotechnical properties when used in marine equipment, for example, in bearing assemblies and internal combustion engines.

[0002] An anti-wear additive to diesel fuel is known, consisting of diesel fuel with micelles in it based on molecules of solid plastic lubricant iron oxide Fe3O4 with surrounding molecules of oleic acid C 18 N 34 O2 at the following ratio of components, mass %: Fe3O4 - 0.00001, C 18 N 34 O2 - 0.0001, diesel fuel - up to 100 (see Russian patent No. 2276681, 2006).

[0003] This additive has a disadvantage: its operating temperature range is limited (from +5 to +80°C) and is insufficient for use in high-temperature friction units of machines and mechanisms. Furthermore, the additive has insufficient tribotechnical properties for use in heavily loaded friction pairs operating at high pressures, temperatures, and speeds.

[0004] The closest in terms of the set of features to the claimed invention (prototype) is an anti-wear additive with micelles in it based on molecules of solid plastic lubricant iron oxide Fe3O4 with surrounding molecules of oleic acid C 18 N 34 O2, while the core of the Fe3O4 micelle is doped with Co (II) in the following ratio of components, mass %: Co (II) - 6, Fe3O4 - 94 (see Russian patent No. 2525404, 2014).

[0005] The additive has a disadvantage of insufficient tribotechnical properties when used in heavily loaded friction pairs operating at high pressures, temperatures and speeds.

[0006] Technical result - improvement of tribotechnical characteristics of the additive.

[0007] It is achieved by the fact that a well-known anti-wear additive, including micelles based on molecules of solid plastic lubricant iron oxide Fe3O4, doped with cobalt Co (II), with surrounding molecules of oleic acid C 18 N 34 O2, additionally contains fullerene nanomodifiers in the form of polyhedral carbon clusters C 60 and C 70 and a powdered metal filler in the form of copper nanopowder Cu in the following ratio of components, mass %:

[0008] With (II) 0,5 Fe3O4 12 S60 8 S70 8 With 16 С18Н34О2 55,5

[0009] The proposed additive is a liquid from the main product - oleic acid C 18 H 34 O2, with the introduction of iron oxide Fe3O4, doped with cobalt Co (I), fullerene nanomodifiers in the form of polyhedral carbon clusters C 60 and C 70 and a powdered metal filler in the form of copper nanopowder Cu.

[0010] Iron oxide Fe3O4 is a micelle core with low shear resistance, surrounded by surfactant molecules - oleic acid C 18 H 34 O2. Oleic acid molecules C 18 N 34O2 is absorbed on the surface of iron oxide Fe3O4 particles as a result of chemisorption. Increasing the concentration of iron oxide Fe3O4 above 12 wt.% becomes economically unprofitable due to the scarcity and high cost of the powder (see Perekrestov A.P., Braiko A.A. Anti-wear additives in diesel fuel and their development / / Vestnik ASTU. - 2008. - No. 2 (43). - P. 218-221).

[0011] The additive particle core, consisting of cobalt-doped iron oxide CoFe2O4, exhibits relatively high magnetic and tribological properties and chemical stability. Compared to a core made of iron oxide Fe3O4, this core exhibits higher magnetic properties—coercive force H с , saturation magnetization σ s and the hysteresis loop squareness coefficient λ п(see Subbotin K.A., Mikhailenko A.I., Nedikova N.V. Effect of synthesis conditions on the magnetic properties of magnetite / / Journal of Applied Chemistry. - 2000. - Vol. 73. - Issue 10. - Pp. 1591-1595; Gaiduk Yu.S., Korobko E.V., Kotikov D.A., Svito I.A., Usenko A.E., Pankov V.V. Production and characterization of cobalt and cobalt-zinc ferrites for magnetorheological materials / / Condensed media and interphase boundaries. - 2022. - No. 24 (1). - Pp. 19-28).

[0012] The concentration of Co (I) is 0.5 wt. % in order to ensure an efficient process of doping Fe2O4 iron oxide using various methods - single-stage, multi-stage or heterophase, which can result in obtaining plate-shaped particles of cobalt-dated iron oxide CoFe2O4 with a size of up to 200 nm (see Subbotin K.A. Development of magnetite modification technology: abstract of a PhD thesis: 05.17.01 / Subbotin Konstantin Alekseevich; D.I. Mendeleyev University of Chemical Technology of Russia. - M., 2000. - 18 p; Nikishina E.E. Heterophase synthesis of cobalt ferrite / / Fine chemical technologies. - 2021. - No. 16 (6). - P. 502-511).

[0013] Particles of cobalt-annealed iron oxide CoFe2O4 in the additive composition promote plating of the friction surfaces of moving tribounits, which significantly improves the tribological characteristics of modified lubricants. Analysis of the results of tribological studies of the friction pair "gray cast iron SChKhN - gray cast iron SChKhNMD" (GOST 1412-85), using a 2070 SMT-1 friction machine, showed that the addition of additives containing CoFe2O4 to MS-20 oil reduces the wear of the test samples by 1.4-1.8 times, and the friction coefficient by 1.2-1.5 times. The presented data indicate that the use of cobalt-annealed iron oxide CoFe2O4 in the additive composition helps to reduce the wear of friction units of machines and mechanisms and increase their service life and reliability (see Barabanov K.N.Modern lubricants used in marine engineering / / 73rd International Student Scientific and Technical Conference, Astrakhan, April 17-22, 2023: materials / Astrakhan State Technical University. - Astrakhan: Publishing house of Astrakhan State Technical University, 2023. - P.1213-1214; Chanchikov V.A., Guzhvenko I.N., Kozlov A.A., Pryamukhina N.V. Development of equipment for evaluating the tribological properties of modified lubricants / / Mechatronics, automation and robotics. Materials of the VIII International scientific and practical conference. - St. Petersburg: NITs MS, 2024. - No. 13. - P.206-215).

[0014] Introduction of fullerene nanomodifiers in the form of polyhedral carbon clusters C into the additive composition 60 and C 70 helps reduce the friction coefficient f тp and linear wear Δh by 1.4 times; increases scuffing resistance (by test time to scuffing under constant load) by an average of 3.6 times, and by critical contact pressure P kpscuff resistance increases by 1.26 times (see Russian patent No. 2268291, 2006).

[0015] Analysis of the test results of the friction pair St.45 (n.) - hardened alloy steel (55 HRC) showed that the addition of 1.0 wt. % fullerene soot to I-40A oil reduces the wear of the roller made of St.45 by 4.16 times, and the friction coefficient by 1.35 times; increases P кр , R схв and critical temperature T кр by 1.17, 2.3, and 1.37 times, respectively, compared to similar characteristics when lubricating a friction pair with pure oil without the addition of soot—a fullerene nanomodifier. The presented data indicate that fullerene soot slightly reduces the friction coefficient, which accordingly limits the expected more significant increase in P кр1 and T кр1 compared to the obtained 17% and 37%, respectively (see Russian patent No. 2146277, 2000).

[0016] Introduction of fullerene nanomodifiers in the form of polyhedral carbon clusters C into the additive composition 60 and C70 at a concentration of 8 wt.% it promotes the formation of a protective metal-fullerene film on friction surfaces, which improves the tribotechnical characteristics of friction units, in particular, it helps reduce the wear of structural materials.

[0017] The introduction of a powdered metal filler in the form of copper nanopowder Cu into the additive composition helps to reduce the friction coefficient by 1.1-1.3 times, and reduce linear wear by 1.2-1.7 times, which is confirmed by the results of comparative tribological tests of the “steel-to-steel” friction pair (50 HRC) according to the “shaft-to-pad” scheme in the environment of I-20 and A-8 lubricating oils. Analysis of the results of extreme pressure tests showed that the introduction of copper nanopowder Cu into base oils helps to increase the seizing load by 1.83 times (see http: / / www.nanosized-powders.com / fields of application / range-of-application / nanopowder doped lubricants.php: Lerner M.I. Electroexplosive nanopowders of inorganic materials: production technology, characteristics, areas of application: abstract of the dissertation of Doctor of Engineering Sciences: 01.04.07 / Lerner Marat Izrailevich; Tomsk Polytechnic University. - Tomsk, 2007. - 38 p).

[0018] The introduction of a powdered metal filler in the form of copper nanopowder Cu at a concentration of 16 wt.% into the additive composition promotes the formation of a protective metal-plating layer on the friction surfaces, caused by the mechanical processes of introducing nanoparticles into the surface layers, and improves the tribotechnical characteristics of the additive.

[0019] The additive was obtained by the following method. The production scheme is shown in the drawing (Fig. 1). The synthesis of Fe2O4 iron oxide doped with cobalt Co(II) was carried out by a one-stage coprecipitation of iron oxide and cobalt hydroxides under vigorous stirring. The resulting CoFe2O4 particles consisted of a base of Fe3O4 (96 wt.%) and Co (4 wt.%). This substance, together with fullerene nanomodifiers in the form of polyhedral carbon clusters C 60 and C 70at a concentration of 8 wt.% and a powdered metal filler in the form of copper nanopowder Cu at a concentration of 16 wt.% was placed in a dispersant bath with oleic acid C 18 H 34 O2, where the dispersion process took place at a temperature of 28-30°C, at a frequency of 43 kHz for 24 hours. Then a solution with micelles of cobalt-doped iron oxide CoFe2O4, particles of fullerene nanomodifiers in the form of polyhedral carbon clusters C 60 and C 70 and particles of powdered metal filler in the form of copper nanopowder Cu were sent to the sedimentation chamber, where they settled for 8 hours.

[0020] The resulting solution was drained and sent for analysis to determine the size of the resulting micelles. The optimal additive particle size range is 10 -7 -10 -8m. The sediment from the sedimentation chamber was sent for re-dispersion, and the solution was also sent there after the process of measuring the size of the additive particles, if they turned out to be larger than the optimum.

[0021] The solution with micelles of the required size was sent to the accumulator. From the accumulator, the solution entered the mixing chamber, where it was mixed with oil at a temperature of 25-30°C and a speed of 300 rpm to produce the final product—a lubricating composition with an additive concentration in the lubricating oil in the range of 0.005-0.02% by weight. This temperature and speed regime was selected to ensure intensive mixing of the components of the lubricating composition while preventing additive evaporation during mixing.

[0022] In order to confirm the improvement of the tribological characteristics of the anti-wear additive and achieve the specified technical result, comparative laboratory tribological tests of the prototype additive and the proposed additive were conducted using a friction machine according to Russian Patent No. 115917, 2012 (test report attached). The tests were carried out according to the "shaft-sleeve" scheme, on the MS-20 base oil (GOST 21743-76) for 10 hours, the pressure in the friction zone was 1.5 MPa. The sliding speed was 0.1 s -1 , which corresponds to the transient (boundary) lubrication regime in the friction pair. The friction pair materials are B83 babbitt (bushing) and grade 45 steel (shaft). The results of tribological testing of antiwear additives are shown in Table 1.

[0023] Tribological test results of antiwear additives

[0024]

[0025] From Table 1, it can be seen that the proposed additive showed higher efficiency, which confirmed its improved tribotechnical characteristics.

[0026] The advantage of the proposed additive over the prototype is its efficiency: reducing its concentration in lubricants does not degrade its quality or performance characteristics. At the same additive concentrations (0.005-0.02 wt.%), the proposed additive exhibits superior tribological properties: the friction coefficient is reduced by 2.1-2.61 times, and wear intensity is reduced by 1.83-2.13 times. This demonstrates the possibility and necessity of reducing the concentration of the proposed additive in lubricants by 25-30%.

[0027] Positive effect - the proposed additive allows, at a relatively low concentration, to significantly reduce the coefficient of friction and the wear rate of friction pairs and, thus, to increase the service life of tribo-units of machines and mechanisms in marine equipment.

Claims

An anti-wear additive comprising micelles based on molecules of solid plastic lubricant iron oxide Fe3O4, alloyed with cobalt Co (II), with surrounding molecules of oleic acid C 18 N 34 O2, characterized in that it additionally contains fullerene nanomodifiers in the form of polyhedral carbon clusters C 60 and C 70 and a powdered metal filler in the form of copper nanopowder Cu with the following ratio of components, mass %: With (II) 0,5 Fe3O4 12 S60 8 S70 8 With 16 С18Н34О2 55,5

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