A dynamic repair in-situ strengthening material for metal wear and its preparation method

Abstract

A dynamic repair in-situ strengthening material for metal wear and its preparation method according to the present invention are prepared by selecting antigorite as the raw material. It is characterized in that the antigorite fine powder is obtained by being modified with an organic surfactant, microwave thermal activation, and magnesium ion exchange treatment. After the antigorite is modified, its compatibility with non-polar media and its dispersion and suspension stability therein are significantly improved. Microwave thermal activation increases the dissolution of silicon and magnesium ions in the antigorite powder and improves the activity of its repair and strengthening reaction. After the magnesium ion exchange modification treatment, the content of Mg<supgt;2+< / supgt; in the antigorite powder is increased, the replacement capacity of Mg<supgt;2+< / supgt> and Fe<supgt;2+< / supgt> in the dynamic repair and strengthening reaction process is increased, and the reaction rate is enhanced. The composition and morphology of the prepared material are clear, and it is applicable to the dynamic repair and in-situ strengthening of the wear surfaces of divalent and trivalent metals, especially iron-based metals, in a wide range, and can significantly increase the thickness of the repair and strengthening layer. The raw materials are environmentally friendly and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the field of surface wear repair treatment of mechanical friction pairs, and particularly relates to a metal wear dynamic repair in-situ strengthening material and a preparation method thereof. Background Art

[0002] Metal wear in mechanical equipment is the main factor leading to equipment damage and increased energy consumption. For a long time, using lubricants, improving the lubricating and friction-reducing performance of lubricating media, and surface strengthening treatment of friction pairs have been the main measures to reduce the wear of friction pairs. However, due to the permanent frictional force existing in the friction pairs, the wear of the friction pairs can never be effectively eliminated. In the past two decades, the technology of dynamically and in-situ repairing the wear of friction pairs and strengthening the surface of friction pairs during equipment operation, also known as the "metal wear self-repair" technology, has developed rapidly. Most of this technology focuses on adding materials to lubricants that have a friction-reducing effect on friction pairs and can more effectively utilize frictional energy during equipment operation to dynamically repair the wear of the friction surface and in-situ form a metallurgical strengthening protective layer with higher hardness and lower dry friction coefficient integrated with the substrate. Among them, serpentine is one of the objects studied more. Its application is to add serpentine powder with appropriate particle size to lubricants such as lubricating oil or grease in a certain proportion, and the lubricant carries it into the surface of the running equipment friction pair. The unsaturated bonds and active groups on the cross-section of the serpentine powder make it easy to be adsorbed on the surface of the iron-based metal friction pair. When the serpentine with a layered structure is subjected to shear force between the friction pairs, interlayer sliding occurs, thereby reducing the frictional resistance. The shear force generated by the relative movement of the friction pairs continuously refines the serpentine powder, even to the nanoscale. The refined microparticles provide good load support between the friction pairs, effectively reducing the contact area of the friction pair interface, and thus playing a significant role in reducing the frictional resistance; the rapid relative movement of the friction pairs causes frictional energy to be generated at the worn convex parts, and the instantaneous high temperature causes a phase change of the serpentine. The hydroxyl groups released by the phase change of the serpentine react with C and H in the lubricating oil and grease to form a continuous polyester film on the surface of the friction pair, which can not only reduce the friction coefficient but also reduce the surface wear of the friction pair; the hydroxyl groups released by the phase change of the serpentine can cause Fe in the iron-based metal component to be oxidized to Fe 2+ or Fe 3+ and then form stable iron oxides or hydroxides; Fe 2+ or Fe 3+ replaces with Mg in the serpentine again 2+ to form more stable iron magnesium silicate, thus showing good friction-reducing and anti-wear effects; the catalytic Ni 2+ released by the phase change of the serpentine can accelerate the formation of the new surface layer and repair layer of the iron-based metal friction pair; the olivine generated by the in-situ phase change of the serpentine has a relatively large density, hardness, and high melting point, and has good thermal stability. The Mg 2+ in it can be replaced by Fe2+ Replacement generates a higher-strength magnesium-ferrosilicate solid solution layer, thereby repairing the worn surface and forming a strengthened layer with a lower friction coefficient. During the repair and strengthening process, the formation of the repair and strengthening layer changes with time and environmental parameters. The thickness is proportional to the frictional energy. After the worn surface is repaired, the frictional energy decreases, the growth of the repair and strengthening layer stops, the thickness reaches a dynamic balance, and the mating clearance of the friction pair is optimized.

[0003] However, there are some problems in the existing technologies: (1) It is not clear that the serpentine used as the functional material for the online dynamic repair and strengthening of iron-based friction pairs should be antigorite. Serpentine is a general term for hydrous magnesium-rich silicate minerals. Such a vague convention according to the serpentine category is very likely to use chrysotile, which has been proven to be carcinogenic to humans and is prohibited internationally, as a functional component, and the potential environmental hazards cannot be ignored or underestimated; (2) The surface of serpentine powder is not modified. The surface of serpentine powder has strong polarity. As the particle size decreases and the specific surface area increases, the agglomeration ability of antigorite powder increases. Serpentine powder without surface modification will strongly agglomerate when added to lubricating oil, resulting in an increase in particle size, causing abrasive grinding and reducing the effect of lubricating oil; (3) The silicon and magnesium ions in serpentine powder are not activated, and the reaction activity for the wear repair of friction pairs and the formation of the strengthening layer is not as expected; (4) There are no specific requirements or treatment measures for the chemical composition of functional serpentine powder. Due to different natural serpentine ore veins and poor composition consistency, especially the Mg 2+ content is insufficient to meet the replacement with Fe 2+ or Fe 3+ During replacement, it is difficult to achieve ideal effects and efficiency. Blindly increasing its addition ratio in the lubricant will lead to an increase in the impurity ratio in the lubricant and affect other functions of the lubricant. In addition, none of the existing repair materials gives a quantitative value for the thickness of the repair and strengthening layer, and there is a difficulty in quantitatively evaluating the effect. Summary of the Invention

[0004] The object of the present invention is to provide a metal wear dynamic repair and in-situ strengthening material and its preparation method with strict constraints on the species of raw ore, environmental friendliness, simple preparation process, clear material composition and morphology, good dynamic repair and in-situ strengthening effects, and high efficiency in view of the deficiencies of the existing technologies.

[0005] The technical solution adopted by the present invention to solve the technical problems is as follows: A metal wear dynamic repair and in-situ strengthening material and its preparation method are prepared by selecting antigorite minerals or natural antigorite without olivine and chrysotile after processing. The characteristics are that the antigorite fine powder is prepared by being modified with an organic surfactant, microwave thermal activation, and magnesium ion exchange treatment;

[0006] For the surface modification of the antigorite powder, one or more of the non-ionic organic surfactants polyoxyethylene sorbitol lanolin oleate derivative, polyoxypropylene mannitol dioleate, polyoxyethylene lanolin alcohol ether, and tetraethylene glycol monooleate are used. The usage amount of the surfactant is 0.04% - 0.08% of the total mass of the antigorite powder. Preferably, the usage amount of the surfactant polyoxyethylene sorbitol lanolin oleate derivative is 0.05% of the total mass of the antigorite powder.

[0007] For the microwave thermal activation of the antigorite powder, the thermal activation temperature is 350°C - 500°C, and the activation time is 15 minutes. Preferably, the thermal activation temperature is 450°C.

[0008] The magnesium ion exchange treatment of the antigorite powder is carried out in an Mg(OH) solution with a molar concentration of 0.5, 0.7, or 0.9 after microwave thermal activation at a temperature of 60°C for ion exchange modification treatment. Preferably, the antigorite powder is subjected to ion exchange modification with an Mg(OH) molar concentration of 0.7. 2 2 exchange modification,

[0009] The chemical composition of the modified powder, calculated by the mass of the oxides of each element, is as follows: SiO content is 43% - 44.5%, MgO content is 42% - 43.5%, FeO content is 1.5% - 2.0%, NiO content is 0.1% - 0.2%, and the structure H 2 O content is 12.7% - 13.5%. 2

[0010] The described metal wear dynamic repair in-situ strengthening material and its preparation method include the following steps:

[0011] Step 1: Screen natural antigorite minerals. When detected by an X-ray powder diffractometer, the presence of olivine and chrysotile should not be detected, and when detected by a polarizing microscope, the presence of olivine and chrysotile should also not be detected. After the screened natural antigorite minerals are coarsely crushed by a jaw crusher, they are then ultra-finely ground by wet grinding in a ball mill under stirring to obtain micro-powder.

[0012] ​​Step 2: Stir and mix the serpentine micro-powder, surfactant and water in a blender for surface modification to obtain a water suspension, and then use a hydrocyclone to perform hydrocyclone classification on the water suspension. Collect the overflow liquid of the serpentine powder with a particle size range of 0.5 - 2.5 μm, and place the obtained overflow liquid in a drying oven to dry to constant weight to obtain 0.5 - 2.5 μm surface-modified serpentine micro-powder;

[0013] Step 3: Heat and activate the surface-modified serpentine powder in a microwave heating furnace, and obtain heat-activated serpentine powder after cooling;

[0014] Step 4: Place the obtained heat-activated serpentine powder in a vertical blender, add it to the Mg(OH) 2 solution, and stir and mix at a temperature of 60 °C for magnesium ion exchange treatment. Place the obtained exchanged serpentine powder and the mixture of Mg(OH) 2 back into the drying oven to dry until constant weight to obtain serpentine powder rich in magnesium ions;

[0015] Step 5: Determine whether the composition of the material by mass of the oxides of each element is qualified through the silicate rock chemical analysis methods of GB / T14506.1 - 14506.28 - 93;

[0016] Step 6: Disperse the dried serpentine powder, and observe the morphology of the serpentine powder after ultrafine grinding, surface modification, heat activation and ion exchange through a scanning electron microscope to obtain a metal wear dynamic repair in-situ strengthening material.

[0017] In a specific embodiment, add the metal wear dynamic repair in-situ strengthening material and the material prepared by its preparation method to lubricating oil to perform on-line dynamic repair in-situ strengthening on the wear of the iron-based friction pair, and the thickness of the formed repair strengthening layer is 5 - 7 μm.

[0018] The beneficial effects of the present invention are that after the serpentine micro-powder is modified by an organic surfactant, its surface polarity and free energy are significantly reduced, and its compatibility with non-polar media such as lubricating oil and grease and its dispersion and suspension stability in them are significantly improved; through microwave heat activation, the dissolution, exchangeability of silicon and magnesium ions in the serpentine powder and the specific surface area of the powder can be increased, and the activity of its repair and strengthening reaction can be improved; after magnesium ion exchange modification treatment, the content of Mg 2+ in the serpentine powder can be increased, and the Mg 2+ in the dynamic repair and strengthening reaction process of the wear surface of the iron-based friction pair 2+ and Fe 3+The replacement capacity is increased to enhance the repair and strengthening reaction rate; the composition and morphology of the prepared material are clear, and it is applicable to the dynamic repair and in-situ strengthening of the worn surfaces of divalent and trivalent metals, especially iron-based metals, in a wide range, and can significantly increase the thickness of the repair and strengthening layer; the raw materials are environmentally friendly and the preparation process is simple. Description of the Drawings

[0019] The following is specifically described by way of examples in conjunction with the drawings.

[0020] Figure 1 : SEM scanning electron microscope photograph of the material morphology prepared in Example 1 of the present invention;

[0021] Figure 2 : SEM scanning electron microscope photograph of the repair and strengthening layer after repairing the iron-based friction pair with the material prepared in Example 1 of the present invention. Embodiment

[0022] Example 1, referring to the attached Figure 1 、 2

[0023] (1) Materials and preparation

[0024] Step 1: Screen natural antigorite minerals. When detected by an X-ray powder diffractometer, the presence of olivine and chrysotile should not be detected, and when detected by a polarizing microscope, the presence of olivine and chrysotile should not be detected either. After the screened natural antigorite minerals are coarsely crushed by a jaw crusher, they are then ultra-finely ground by wet grinding in a ball mill under stirring to obtain micro-powder.

[0025] Step 2: Stir and mix 20 kg of antigorite micro-powder, 10 g of the surfactant polyoxyethylene sorbitan lanolin oleic acid derivative, and 180 kg of water in a vertical mixer for 120 min to obtain a water suspension containing micro-powder and surfactant. Then, use a GSDF50 cyclone with a working pressure of 0.3 MPa to perform hydrocyclone classification on this water suspension. Use a BT-9300ST laser particle size distribution analyzer to measure the powder size online, and collect the overflow liquid of the powder with a particle size range of 0.5 - 2.5 μm. Place the obtained overflow liquid in an HB881-8 drying oven and dry it at 105 °C until constant weight to obtain surface-modified antigorite powder with a particle size range of 0.5 - 2.5 μm.

[0026] Step 3: Heat the obtained surface-modified antigorite powder in a microwave heating furnace to 450 °C and keep it for 15 min, and then naturally cool it with the furnace to obtain thermally activated antigorite powder.

[0027] Step 4: Place 20 kg of the obtained thermally activated antigorite powder in a vertical mixer, and add 30 kg of Mg(OH) with a molar concentration of 0.72 In the solution, when the temperature is 60 °C, stirring and mixing are carried out for 20 min for magnesium ion exchange modification treatment. The obtained modified antigorite powder and the mixture of Mg(OH) 2 are then placed in an HB881-8 drying oven and dried at 105 °C until a constant weight is obtained to get the magnesium-rich antigorite micro-powder.

[0028] Step 5: As a result, it is determined by the chemical analysis methods of silicate rocks GB / T14506.1 - 14506.28 - 93 that

[0029] According to the composition by mass of the oxides of each element in the antigorite powder: the content of SiO 2 is 43% - 44.5%, the content of MgO is 42% - 43.5%, the content of FeO is 1.5% - 2.0%, the content of NiO is 0.1% - 0.2%, and the content of structural H 2 O is 12.7% - 13.5%.

[0030] Step 6: The antigorite micro-powder processed through the above process is dispersed using an MGS high-speed disperser. The morphology and dispersion state of the antigorite powder after ultra-fine grinding, surface modification, thermal activation, and ion exchange are observed using an S4800 cold field emission scanning electron microscope, and the particle size of the powder is measured. As a result, it can be seen from the appendix Figure 1 that the powder of a metal wear dynamic repair in-situ strengthening material obtained is well-dispersed, and the particle size of the powder is 0.5 - 2.5 μm. Thus, the required metal wear dynamic repair in-situ strengthening material is obtained.

[0031] (2) Tribological property evaluation

[0032] The above-prepared dynamic repair in-situ strengthening material is mixed with PAO40 polyalphaolefin synthetic base oil and dispersed by an EYG-600W ultrasonic disperser for 30 min to obtain a lubricating oil with a solid content of 0.02% by mass; an appropriate amount of the lubricating oil with a solid content of 0.02% by mass is added to the oil sump of an MM-10W type end face friction test machine, and the load is set at 200 N, the rotational speed is 1200 r / min, the friction time is 48 h, and the test environment temperature is 25 °C ± 2 °C; both the upper and lower specimens are 45 steel with a hardness of HB210 and are lubricated with immersion oil. After the friction test, after the specimen cross-section is treated with a nitric acid alcohol etching solution, the cross-section characteristics are observed using an SEM scanning electron microscope. The lamellar pearlite structure can be clearly seen in the steel matrix part, while the repaired and strengthened layer does not show the pearlite characteristics, so as to distinguish the interface between the repaired and strengthened layer and the matrix. As an application effect, it can be seen from the appendix Figure 2 that the repaired and strengthened layer of the specimen is clearly visible, and the thickness is 5.187 μm - 6.764 μm. Example

[0033] (1) Materials and Preparation

[0034] Except for performing ion exchange treatment with a 0.9 molar concentration of Mg(OH) 2 solution, a metal wear dynamic repair in-situ strengthening material was prepared by the same other processes as in Example 1, and the same component detection and analysis as in Example 1 were carried out on it.

[0035] (2) Tribological Performance Evaluation

[0036] Friction experiments and determination of the thickness of the repair and strengthening layer were carried out under the same procedures and conditions as in Example 1. The thickness of the repair and strengthening layer of this specimen was between 2.79 μm and 3.81 μm. Example

[0037] (1) Materials and Preparation

[0038] Except for performing ion exchange treatment with a 0.5 molar concentration of Mg(OH) 2 solution, a metal wear dynamic repair in-situ strengthening material was prepared by the same other processes as in Example 1, and the same component detection and analysis as in Example 1 were carried out on it.

[0039] (2) Tribological Performance Evaluation

[0040] Friction experiments and determination of the thickness of the repair and strengthening layer were carried out under the same procedures and conditions as in Example 1. The thickness of the repair and strengthening layer of this specimen was between 3.19 μm and 3.51 μm.

[0041] Comparative Example 1

[0042] (1) Materials and Preparation

[0043] Except for not performing ion exchange treatment with Mg(OH) 2 solution, a metal wear dynamic repair in-situ strengthening material was prepared by the same other processes as in Example 1, and the same component detection and analysis as in Example 1 were carried out on it.

[0044] (2) Tribological Performance Evaluation

[0045] Friction experiments and determination of the thickness of the repair and strengthening layer were carried out under the same procedures and conditions as in Example 1. The thickness of the repair and strengthening layer of this specimen was between 0.2 and 1.0 μm.

[0046] Comparative Example 2

[0047] (1) Materials and Preparation

[0048] Except for the antigorite powder without microwave thermal activation, a metal wear dynamic repair in-situ strengthening material was prepared by the same other processes as in Example 1, and the same component detection and analysis as in Example 1 were carried out on it.

[0049] (2)Tribological property evaluation

[0050] The friction experiment and the determination of the thickness of the repair and strengthening layer were carried out under the same procedures and conditions as in Example 1. The thickness of the repair and strengthening layer of this specimen was 0.4 - 2.5 μm.

[0051] From the results of the above Examples 1 - 3, it can be seen that a metal wear dynamic repair in-situ strengthening material composed of antigorite powder with specific chemical composition and morphology after microwave thermal activation, Mg(OH) 2 solution ion exchange treatment and surface modification has a good repair and strengthening effect on the worn surface of the iron-based friction pair.

[0052] At the same time, from the results of Comparative Examples 1 - 2, it can be seen that materials that do not meet the composition requirements of the present invention without magnesium ion exchange, or materials prepared from non-activated antigorite, cannot fully achieve the repair and strengthening effect and efficiency expected by the present invention.

[0053] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various changes and adjustments can be made to the technical solutions of the present invention, and these changes and adjustments all fall within the protection scope of the present invention.

Claims

1. A preparation method of an in-situ strengthening material for dynamic repair of metal wear, Characterized in that, It includes the following steps: (1) Screen natural antigorite minerals. When detected by an X-ray powder diffractometer, the presence of olivine and chrysotile should not be detected, and when detected by a polarized light microscope, the presence of olivine and chrysotile should also not be detected. After the screened natural antigorite minerals are coarsely crushed by a jaw crusher, they are then ultra-finely ground by wet grinding in a ball mill under stirring to obtain micro-powder. (2) Mix 20 kg of antigorite micro-powder with 10 g of the surfactant polyoxyethylene sorbitan lanolin oleate derivative and 180 kg of water in a vertical mixer and stir for 120 min to obtain a water suspension containing micro-powder and surfactant. Then, use a GSDF50 cyclone with a working pressure of 0.3 MPa to perform hydrocyclone classification on this water suspension. Use a BT-9300ST laser particle size distribution analyzer to measure the powder size online, and collect the overflow liquid of the powder with a particle size range of 0.5 - 2.5 μm. Place the obtained overflow liquid in an HB881-8 drying oven and dry at 105°C until constant weight to obtain surface-modified antigorite powder with a particle size range of 0.5 - 2.5 μm. (3) Heat the obtained surface-modified antigorite powder in a microwave heating furnace to 450°C and keep it for 15 min, and then naturally cool it in the furnace to obtain thermally activated antigorite powder. (4) Place 20 kg of the obtained thermally activated antigorite powder in a vertical mixer, add it to a solution of 30 kg of Mg(OH) 2 with a molar concentration of 0.

7. Stir and mix at 60°C for 20 min for magnesium ion exchange modification treatment. Place the obtained modified antigorite powder and the mixture of Mg(OH) 2 back into the HB881-8 drying oven and dry at 105°C until constant weight to obtain magnesium-rich antigorite micro-powder.

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