Micro pitting corrosion repairing additive as well as preparation method and application thereof

Abstract

The invention relates to the technical field of micro-pitting repair, in particular to a micro-pitting repair additive as well as a preparation method and application thereof. The micro pitting corrosion repairing additive provided by the invention is layered silicate non-covalently modified by ionic liquid; the ionic liquid is one or more of phosphate ammonium salt, thiophosphate ammonium salt and phosphate phosphonium salt. The micro-pitting repair additive provided by the invention has a good repair effect on formed micro-pitting, can realize online repair, does not need to stop, and saves the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-pitting repair, in particular to a micro-pitting repair additive, a preparation method and application thereof. BACKGROUND

[0002] As a main form of rolling contact fatigue (RCF), micro-pitting widely exists in high-load mechanical components such as gears and bearings, and the micro-cracks (μm level) caused by micro-pitting significantly reduce the fatigue life of the components.

[0003] Although traditional additives (such as zinc dialkyldithiophosphate (ZDDP)) can improve the anti-wear performance, the high-activity sulfur and phosphorus components thereof accelerate the propagation of micro-cracks and aggravate micro-pitting. Although nanoparticles (such as CuO and CNTs) can delay micro-pitting, they have insufficient repair capacity for the damage that has been formed, and have poor dispersion stability in gear oil.

[0004] In the past, the phenomenon of micro-pitting on the metal surface is often restored by grinding, polishing, filling materials, electroplating and other methods to restore the surface cleanliness and flatness. However, these methods require shutdown operation and are costly. SUMMARY

[0005] Therefore, the present application aims to provide a micro-pitting repair additive, a preparation method and application thereof. The micro-pitting repair additive provided by the present application has good repair effect on the micro-pitting that has been formed, and can realize online repair without shutdown, thereby saving cost.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a micro-pitting repair additive, which comprises a layered silicate and an ionic liquid modified on the layered silicate; the ionic liquid is one or more of ammonium phosphate ester salt, ammonium thiophosphate ester salt and phosphonate salt.

[0008] Preferably, the layered silicate comprises one or more of magnesium hydroxyl silicate, kaolin, talc, bentonite and muscovite.

[0009] Preferably, the particle size of the layered silicate is 1-5 μm.

[0010] Preferably, the ionic liquid is composed of anions and cations.

[0011] When the ionic liquid is ammonium phosphate ester salt, the anion comprises di(2-ethylhexyl) phosphate ester anion, and the cation comprises n-octylamine cation, trioctylamine cation, dodecylamine cation, dodecenyl succinyl diethylene triamine cation or oleylamine cation.

[0012] When the ionic liquid is an ammonium thiophosphate salt, the anion comprises a diisobutyl dithiophosphate anion or a diisobutyl dithiophosphoryl acrylate anion, and the cation comprises a n-octylamine cation, a trioctylamine cation, a dodecylamine cation or an oleylamine cation;

[0013] When the ionic liquid is a phosphonium phosphate salt, the anion comprises a di(2-ethylhexyl) phosphate anion, a dihexyl phosphate anion or a diisodecyl phosphate anion, and the cation comprises a tetrabutylphosphonium cation or a trihexyldecylphosphonium cation.

[0014] Preferably, the mass ratio of the layered silicate to the ionic liquid is 7-10:1.

[0015] The present application provides a preparation method of the micro-pitting repair additive described in the above scheme, comprising the following steps: mixing the ionic liquid, the layered silicate and the organic solvent to perform ultrasonic treatment, and then performing solid-liquid separation to obtain the micro-pitting repair additive.

[0016] Preferably, the mass ratio of the ionic liquid to the layered silicate is 2-5:1, and the mass ratio of the layered silicate to the solvent is 1:20-50.

[0017] Preferably, the ultrasonic treatment is performed for 6-24h at a temperature of 50-80℃ and a power of 90-150W.

[0018] The present application provides a gear oil composition comprising the micro-pitting repair additive and gear oil; the mass of the micro-pitting repair additive is 0.2-2% of the mass of the gear oil; the micro-pitting repair additive is the micro-pitting repair additive described in the above scheme or the micro-pitting repair additive prepared by the preparation method described in the above scheme.

[0019] The present application provides a method for repairing gear micro-pitting, which comprises adding the gear oil composition described in the above scheme to the surface of the gear to perform online repair.

[0020] The application provides a micropitting repair additive, comprising a layered silicate and an ionic liquid modified on the layered silicate; the ionic liquid is one or more of ammonium phosphate ester, ammonium thiophosphate ester and phosphine phosphate.

[0021] The micropitting repair additive provided by the application is added into gear oil to form a gear oil composition, which can realize dynamic repair of micropitting in the operation of equipment, without shutdown and cost saving. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The micropitting repair effect diagram and the friction coefficient change diagram of each application example and application comparative example;

[0023] Figure 2 The nuclear magnetic resonance hydrogen spectrum (a) of diisobutyl dithiophosphate tricapryl ammonium salt ionic liquid, the XRD diagram (b) of artificially synthesized magnesium hydroxyl silicate, and the infrared spectrum (c) of the micropitting repair additive prepared in Example 1. DETAILED DESCRIPTION

[0024] The application provides a micropitting repair additive, comprising a layered silicate and an ionic liquid modified on the layered silicate; the ionic liquid is one or more of ammonium phosphate ester, ammonium thiophosphate ester and phosphine phosphate.

[0025] In the application, the layered silicate preferably comprises one or more of magnesium hydroxyl silicate, kaolin, talcum powder, bentonite and mica. Among them, the main component of talcum powder is hydrous magnesium silicate, which belongs to layered silicate (phyllosilicate); bentonite is a hydrous silicate mineral mainly composed of montmorillonite. In the application, the particle size of the layered silicate is preferably 1-5 μm, which can be 1 μm, 2 μm, 3 μm, 4 μm or 5 μm in specific embodiments.

[0026] In the present application, the layered silicate has a layered structure (such as 2:1 talc structure) with silicon-oxygen tetrahedral sheets and metal hydroxide octahedral sheets alternately stacked, the interlayer distance can be dynamically adjusted by ion exchange or intercalation, the interlayer functional groups (such as hydroxyl groups) can form non-covalent bonds with the ionic liquid, and the dispersion stability in the gear oil is improved by the steric hindrance and electrostatic stabilization of the ionic liquid. In addition, the complex film of silicon oxide and silicon carbide formed by the reaction of the decomposition products of the layered silicate and the amorphous carbon in the base oil during the friction process has high strength and toughness, which can effectively inhibit the formation of micro-pitting.

[0027] In the present application, the ionic liquid is preferably composed of anions and cations.

[0028] When the ionic liquid is an ammonium phosphate ester salt, the anion preferably includes a di(2-ethylhexyl) phosphate anion, and the cation preferably includes a n-octylamine cation, a trioctylamine cation, a dodecylamine cation, a dodecenyl succinic acid diethylene triamine cation, or an oleylamine cation.

[0029] When the ionic liquid is an ammonium thiophosphate ester salt, the anion preferably includes a diisobutyl dithiophosphate anion or a diisobutyl dithiophosphate propylene anion, and the cation preferably includes a n-octylamine cation, a trioctylamine cation, a dodecylamine cation, or an oleylamine cation.

[0030] When the ionic liquid is a phosphonium phosphate salt, the anion preferably includes a di(2-ethylhexyl) phosphate anion, a dihexyl phosphate anion, or a diisodecyl phosphate anion, and the cation preferably includes a tetrabutylphosphonium cation or a trihexyldecylphosphonium cation.

[0031] In an embodiment of the present application, the ionic liquid is diisobutyl dithiophosphate trioctylammonium salt or dodecenyl succinic anhydride functionalized di(2-ethylhexyl) phosphate ammonium salt (anion: di(2-ethylhexyl) phosphate, cation: dodecenyl succinic acid diethylene triamine cation).

[0032] In the present application, the mass ratio of the layered silicate to the ionic liquid is preferably 7-10:1, and in specific embodiments, it can be 7:1, 8:1, 9:1, or 10:1.

[0033] In the present application, the ionic liquid and the layered silicate are connected by non-covalent bonds, specifically by weak forces such as hydrogen bonds, van der Waals forces, and electrostatic interactions.

[0034] The present application uses ionic liquid to modify the layered silicate, which improves the dispersibility of the layered silicate in the gear oil. In addition, the ionic liquid can also improve the lubrication performance of the surface to be repaired.

[0035] The application provides a preparation method of the micro-pitting repair additive.

[0036] In the application, the ionic liquid and the layered silicate are prepared by a method known in the art or are commercially available.

[0037] In the application, the mass ratio of the ionic liquid to the layered silicate is preferably 2-5:1, and can be 2:1, 3:1, 4:1 or 5:1 in specific embodiments; and the mass ratio of the layered silicate to the solvent is preferably 1:20-50, and can be 1:20, 1:30, 1:40 or 1:50 in specific embodiments.

[0038] In the application, the organic solvent preferably comprises one or more of petroleum ether, toluene and xylene; and the organic solvent used in the application is a green solvent and is environmentally friendly.

[0039] In the application, the ultrasonic treatment time is preferably 6-24 h, and can be 6, 10, 14, 18, 20 or 24 h in specific embodiments; the ultrasonic treatment temperature is preferably 50-80 DEG C, and can be 50, 60, 70 or 80 DEG C in specific embodiments; and the ultrasonic treatment power is preferably 90-150 W, and can be 90, 100, 120, 130, 140 or 150 W in specific embodiments. The ionic liquid is used to modify the layered silicate by ultrasonic treatment.

[0040] The application does not have special requirements for the solid-liquid separation method, and a solid-liquid separation method known in the art can be used, for example, centrifugation. When the centrifugation is used, the centrifugation speed is preferably 5000-10000 r / min.

[0041] After the solid-liquid separation is completed, the obtained solid is preferably washed and dried to obtain the micro-pitting repair additive.

[0042] The application does not have special requirements for the drying conditions, and a drying condition known in the art can be used, for example, 80 DEG C vacuum drying.

[0043] In the application, the raw materials of the micro-pitting repair additive are easy to obtain, the preparation cost is low, and the preparation method is simple.

[0044] The application provides a gear oil composition comprising the micro-pitting repair additive and gear oil.

[0045] The present application has no special requirements for the gear oil, and any brand of synthetic industrial gear oil on the market can be used, such as Fos CLP series, Mobil SHC series, and Shell Omala series. In the embodiment of the present application, the gear oil is specifically Fos all-synthetic gear oil CLP150.

[0046] In the embodiment of the present application, the mass of the micro-pitting repair additive can be specifically 0.2%, 0.5%, 1%, 1.5%, or 2% of the mass of the gear oil.

[0047] The present application has no special requirements for the preparation method of the gear oil composition, and the micro-pitting repair additive can be directly and uniformly dispersed in the gear oil. In the embodiment of the present application, the micro-pitting repair additive is added to the gear oil, and stirred at 60℃ for 2h.

[0048] The present application provides a method for repairing micro-pitting of a gear, which adds the gear oil composition described above to the surface of the gear for online repair.

[0049] The present application can achieve dynamic repair of micro-pitting during operation of the equipment, without shutdown, thereby saving cost.

[0050] The micro-pitting repair additive, the preparation method and application thereof provided by the present application will be described in detail below in combination with embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0051] Source of raw materials:

[0052] The diisobutyl dithiophosphoric acid ester trioctyl ammonium salt used in the following examples and comparative examples is obtained by self-preparation, and the preparation method is as follows:

[0053] To the petroleum ether solution of 1 mol of diisobutyl dithiophosphoric acid ester, drop 1 mol of trioctylamine, and react at 80℃ for 12h. The solvent is removed by rotary evaporation to obtain diisobutyl dithiophosphoric acid ester trioctyl ammonium salt ionic liquid.

[0054] The diisobutyl dithiophosphoric acid ester trioctyl ammonium salt is characterized by nuclear magnetic hydrogen spectrum, and the results are shown in Figure 2 (a), it can be seen from Figure 2 (a) that the diisobutyl dithiophosphoric acid ester trioctyl ammonium salt is successfully synthesized.

[0055] The magnesium hydroxyl silicate used in the following examples and comparative examples is artificially synthesized (in order to exclude the interference of impurities), and the synthesis method is as follows:

[0056] MgCl2·6H2O and Na2SiO3·9H2O were weighed according to a molar ratio of 3:2, dissolved in 10 times the mass of deionized water, the pH value of the solution was adjusted to 13-14 by adding NaOH, then stirred and ultrasonicated to ensure uniformity and transferred to an autoclave for hydrothermal synthesis at 200℃ for 24h, and the synthesis product was treated by centrifugal filtration and drying to obtain the final product magnesium hydroxyl silicate.

[0057] The artificial magnesium hydroxyl silicate was subjected to XRD test and compared with the PDF standard card, and the results are shown in Figure 2 As shown in (b) of FIG. 1, the magnesium hydroxyl silicate was successfully synthesized.

[0058] The dodecenyl succinic anhydride functionalized di(2-ethylhexyl) phosphate ammonium salt used in the following examples and comparative examples was obtained by laboratory self-preparation, and the specific preparation method was as follows:

[0059] Dodecenyl succinic anhydride and diethylenetriamine were dissolved in petroleum ether according to a molar ratio of 1:1, stirred at 160℃ for 2h, then cooled to 80℃, and an equimolar amount of di(2-ethylhexyl) phosphate was added dropwise to the dodecenyl succinic anhydride, and the stirring reaction was continued for 3h. Finally, the solvent was removed by vacuum distillation, and vacuum drying was performed to obtain the dodecenyl succinic anhydride functionalized di(2-ethylhexyl) phosphate ammonium salt. The preparation method is referred to the above diisobutyl dithiophosphate tricaprylyl ammonium salt.

[0060] Example 1

[0061] In a three-necked flask, 3g of diisobutyl dithiophosphate tricaprylyl ammonium salt was added, 1g of magnesium hydroxyl silicate was added, and 30mL of petroleum ether was added. After stirring at 60℃ for 12h, the mixture was centrifuged at 5000r / min after cooling to room temperature. After washing with petroleum ether twice, vacuum drying was performed at 80℃ to obtain a micro-pitting repair additive.

[0062] The magnesium hydroxyl silicate (MSH), diisobutyl dithiophosphate tricaprylyl ammonium salt (IL) and micro-pitting repair additive (IL / MSH) were subjected to infrared characterization, and the results are shown in Figure 2 As shown in (c) of FIG. 2, the diisobutyl dithiophosphate tricaprylyl ammonium salt was successfully modified onto the magnesium hydroxyl silicate. Figure 2 As shown in (c) of FIG. 2, the diisobutyl dithiophosphate tricaprylyl ammonium salt was successfully modified onto the magnesium hydroxyl silicate.

[0063] Example 2

[0064] The difference between Example 1 and Example 2 is that the artificial magnesium hydroxyl silicate is replaced by talc powder (particle size 2μm), and the other process parameters and operating conditions are the same as those of Example 1.

[0065] Example 3

[0066] The difference from Example 1 is that the artificial synthetic magnesium hydroxyl siliconate is replaced by kaolin (particle size 2 μm), and other process parameters and operating conditions are exactly the same as Example 1.

[0067] Example 4

[0068] The difference from Example 1 is that the diisobutyl dithiophosphoric acid ester trioctyl ammonium salt is replaced by dodecenyl succinic anhydride functionalized di(2- ethylhexyl) phosphoric acid ester ammonium salt, and other process parameters and operating conditions are exactly the same as Example 1.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the artificial synthetic magnesium hydroxyl siliconate is replaced by graphite (particle size 2 μm), and other process parameters and operating conditions are exactly the same as Example 1.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the artificial synthetic magnesium hydroxyl siliconate is replaced by molybdenum disulfide (particle size 2 μm), and other process parameters and operating conditions are exactly the same as Example 1.

[0073] Application Example 1

[0074] 0.5% of the micro-pitting repair additive prepared in Example 1 is added to the Fuchs all synthetic gear oil CLP150, and the gear oil composition is formed by stirring at 60°C for 2h.

[0075] Application Examples 2-4

[0076] The difference from Application Example 1 is only that the micro-pitting repair additive of Example 1 is replaced by the micro-pitting repair additive of Examples 2-4.

[0077] Comparative Application Examples 1-2

[0078] The difference from Application Example 1 is only that the micro-pitting repair additive of Example 1 is replaced by the micro-pitting repair additive of Comparative Examples 1-2

[0079] Comparative Application Example 3

[0080] is a gear oil composition formed by adding 0.5% of the artificial synthetic magnesium hydroxyl siliconate to the Fuchs all synthetic gear oil CLP150, and stirring at 60°C for 2h.

[0081] Comparative Application Example 4

[0082] is a gear oil composition formed by adding 0.5% of the artificial synthetic magnesium hydroxyl siliconate to the Fuchs all synthetic gear oil CLP150, and stirring at 60°C for 2h.

[0083] Comparative Application Example 5

[0084] To add 0.5% diisobutyl dithiophosphoric acid trioctyl ammonium salt to the Fuchs full synthetic gear oil CLP150, the gear oil composition formed by stirring at 60°C for 2h.

[0085] The anti-micropitting repair performance of the gear oil compositions of each application example and the comparative application example was investigated. The anti-micropitting repair performance test: the micropitting test was carried out using the MPR tester produced by the British PCS company. The test conditions were temperature 60°C, test main load 150N, entrainment speed 2m / s, and slide-roll ratio 5%. The roller and the ring were made of carburized 16MnCr5, the roller hardness was 680±20HV, the roughness Ra was 0.2±0.02μm, the ring hardness was 780±20HV, and the roughness Ra was 0.4±0.02μm. The experiment was an online repair under the sliding-rolling condition. The friction coefficient change graph during the test was drawn, and after the test was completed, the micropitting area was calculated by observing the roller surface micropitting state before and after repair using a metallographic microscope and using software. The results are shown in Table 1. Figure 1 and Table 1.

[0086] Table 1 Micropitting area repair rate of different gear oil compositions

[0087]

[0088]

[0089] According to Figure 1 and Table 1, the following conclusions can be drawn:

[0090] The micropitting repair effect of application examples 1-3, under the action of the ionic liquid modified layered silicate mineral composite additive, the micropitting area of the roller surface was significantly reduced, and the friction coefficient showed a regular downward trend, which verified the synergistic lubrication mechanism of ionic liquid and layered silicate material (magnesium hydroxyl silicate, talc, and kaolin), and application example 4 also had the same effect, but different structures of ionic liquid showed differences in micropitting repair efficiency.

[0091] Compared with application example 1, the solid particles in comparative application example 4 were not modified by ionic liquid, and due to poor dispersibility, they were deposited at the bottom during the test, and the overall repair effect was discounted. This also reflects the dispersing effect of ionic liquid on solid particles and the synergistic repair of micropitting. Note: Comparative example 4 is magnesium hydroxyl silicate without ionic liquid modification, and example 2 is talc modified by ionic liquid. Talc has a lower Mohs hardness and better lubrication effect, but its repair effect is inferior to that of magnesium hydroxyl silicate. Therefore, although the dispersibility of magnesium hydroxyl silicate is poor, it still brings good repair effect under the content of 0.5% through friction stirring, so the repair rate of comparative application example 4 is slightly higher than that of application example 2.

[0092] When the layered silicate is replaced by graphite (Comparative Application Example 1) or molybdenum disulfide (Comparative Application Example 2), the friction coefficient remains stable, and there is no statistically significant difference in the micro-pitting repair area. This shows that such layered solid lubricants can achieve friction reduction and wear resistance by interlayer shear of the sliding surface, but cannot inhibit the formation and expansion of micro-pitting due to the lack of high-strength silicon oxide and silicon carbide composite film, resulting in limited surface repair effect.

[0093] In the gear oil system without the addition of micro-pitting repair additives (Comparative Application Example 3), the friction coefficient shows a linear upward trend with the extension of the sliding-rolling contact time, and the micro-pitting crack expansion rate is more than 45%. This result confirms the self-catalytic expansion characteristics of micro-pitting without repair intervention, and further highlights the technical advantages of the additive of the present application in inhibiting the accumulation of fatigue damage.

[0094] The addition of a single ionic liquid in Comparative Application Example 5 can improve the extreme pressure lubricity of the gear oil, but has no obvious effect on the repair performance, and the results are similar to those of Comparative Application Example 3.

[0095] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A micro-pitting repair additive characterized in that, The layered silicate and the ionic liquid modified on the layered silicate; the ionic liquid is one or more of ammonium phosphate ester, ammonium thiophosphate ester and phosphonium phosphate.

2. The micro-pitting repair additive of claim 1, wherein, The layered silicate comprises one or more of magnesium hydroxyl silicate, kaolin, talc, bentonite and mica.

3. The micro-pitting repair additive according to claim 1 or 2, characterized in that, The particle size of the layered silicate is 1-5 μm.

4. The micro-pitting repair additive of claim 1, wherein, The ionic liquid is composed of anions and cations; When the ionic liquid is ammonium phosphate ester, the anion comprises di(2-ethylhexyl) phosphate anion, and the cation comprises n-octylamine cation, trioctylamine cation, dodecylamine cation, dodecenyl succinyl diethylene triamine cation or oleylamine cation; When the ionic liquid is ammonium thiophosphate ester, the anion comprises diisobutyl dithiophosphate anion or diisobutyl dithiophosphate propylene anion, and the cation comprises n-octylamine cation, trioctylamine cation, dodecylamine cation or oleylamine cation; When the ionic liquid is phosphonium phosphate, the anion comprises di(2-ethylhexyl) phosphate anion, dihexyl phosphate anion or diisodecyl phosphate anion, and the cation comprises tetrabutyl phosphate cation or trihexyldecyl phosphate cation.

5. The micro-pitting repair additive according to claim 1, 2 or 4, characterized in that, The mass ratio of the layered silicate to the ionic liquid is 7-10:

1.

6. A process for the preparation of the micro-pitting repair additive according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: The ionic liquid, the layered silicate and the organic solvent are mixed and subjected to ultrasonic treatment, and then solid-liquid separation is performed to obtain the micro-pitting repair additive.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the ionic liquid to the layered silicate is 2-5:1, and the mass ratio of the layered silicate to the solvent is 1:20-50.

8. The production method according to claim 6 or 7, characterized by, The ultrasonic treatment is performed for 6-24 h at a temperature of 50-80 °C and a power of 90-150 W.

9. A gear oil composition characterized in that, The gear oil composition of claim 9 is added to the surface of a gear for online repair.

10. A method of repairing micropitting of a gear, characterized by, The gear oil composition of claim 9 is added to the surface of a gear for online repair.

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