Preparation method of metal surface nano coating for metal processing

Abstract

The invention discloses a preparation method of a metal surface nano coating for metal processing, which comprises the following steps: S1, carrying out laser processing on the surface of a metal piece to form a plurality of micron-sized elliptical hole structures; s2, the surface of the porous structure metal part is coated with a microcapsule filler; s3, after the microcapsule filler is dried, a nano coating solution is applied, and the drying time is 0.5-1 h; s4, the coated metal part is subjected to heating treatment, so that the microcapsules are broken, and inclusions are released to fill the porous structure; s5, the metal part is cooled, the cooling time ranges from 1 h to 2 h, and the filling layer is solidified; the microcapsule filler enhances the adhesive force between the surface of the metal part and the nano coating, after the porous structure formed by laser processing on the surface of the metal part is filled with the microcapsule filler, microcapsules are broken in the heating treatment process and release inclusions, the porous structure is filled with the microcapsules, micro unevenness on the metal surface is filled and leveled up, and the surface of the metal part is coated with the nano coating. And the nano coating can be attached to the surface of the metal piece more tightly.

Description

Technical Field

[0001] The invention relates to the field of metal processing, and in particular to a method for preparing a metal surface nano coating for metal processing. Background Art

[0002] In the field of metal processing, surface protection of metal parts has always been an important research topic. During use, metal parts are easily damaged by corrosion, wear and scratches due to long-term exposure to air or in a complex working environment, which affects their service life and performance. Although traditional metal surface protection methods, such as electroplating and spraying, can improve the protective performance of metal parts to a certain extent, they often have problems such as uneven coating, easy peeling, and poor corrosion resistance.

[0003] In recent years, the rapid development of nanotechnology has provided new ideas for metal surface protection. Nanomaterials have shown great application potential in the field of metal surface protection due to their unique physical and chemical properties. Nano coatings, especially coatings with nano titanium dioxide as the main component, have become an ideal choice for metal surface protection due to their excellent corrosion resistance, wear resistance and UV protection. However, nano coatings often have problems such as nano material agglomeration and poor dispersion during the preparation process, resulting in unstable coating quality and reduced protective performance.

[0004] In addition, the porous structure of the metal surface is also one of the key factors affecting the quality of the coating. The porous structure of the metal surface not only provides a channel for the corrosive medium to enter the metal surface, but also reduces the adhesion between the coating and the metal surface, making the coating easy to peel off. Therefore, how to form a uniform and dense coating on the surface of the metal and improve the adhesion between the coating and the metal surface is an urgent problem to be solved in metal surface protection technology.

[0005] Therefore, it is necessary to improve a method for preparing a metal surface nano-coating for metal processing in the prior art to solve the above problems. Summary of the invention

[0006] The invention overcomes the shortcomings of the prior art and provides a method for preparing a metal surface nano coating for metal processing.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a metal surface nano coating for metal processing, comprising the following steps:

[0008] S1: Laser processing the surface of a metal part to form a number of micrometer-level elliptical hole structures;

[0009] S2: coating the microcapsule filler on the surface of the porous metal part;

[0010] S3: After the microcapsule filler is dried, the nanocoating solution is applied, and the drying time is 0.5-1h;

[0011] S4: heating the coated metal part to rupture the microcapsules and release the contents to fill the porous structure;

[0012] S5: Cool the metal part for 1-2 hours to solidify the filling layer.

[0013] In a preferred embodiment of the present invention, the method for preparing the microcapsule filler comprises the following steps:

[0014] A1: Select thermosetting resin as the content of microcapsules;

[0015] A2: Choose polyurethane as the shell material of microcapsules;

[0016] A3: The microcapsule filler is prepared by encapsulating the selected contents inside the microcapsules formed by the shell material using the emulsification technology.

[0017] In a preferred embodiment of the present invention, the formula of the nano coating solution includes: the nano coating solution includes: nano material: nano titanium dioxide 5-15%; solvent: ethanol 70-90%; dispersant: polyvinyl pyrrolidone 0.1-5%; stabilizer: silane coupling agent 0.1-5%; additive: corrosion resistance agent 1-10%.

[0018] In a preferred embodiment of the present invention, the method for preparing the nano coating solution comprises the following steps:

[0019] B1: Mix the solvent, dispersant, stabilizer and additives evenly, then add the nanomaterials and continue stirring with a stirrer until the nano coating solution is completely dispersed;

[0020] B2: The nanocoating solution was sonicated using an ultrasonic disperser while stirring.

[0021] In a preferred embodiment of the present invention, in S4, the heating temperature of the heating treatment is 80-100° C., and the heating time is 20-40 min.

[0022] In a preferred embodiment of the present invention, in A1, the thermosetting resin has a heating expansion effect.

[0023] In a preferred embodiment of the present invention, in A2, the polyurethane is efficiently combined with the dispersant in the nano-coating solution.

[0024] In a preferred embodiment of the present invention, the mass ratio of the inclusions to the shell material is 30:70-70:30.

[0025] In a preferred embodiment of the present invention, in B1, the stirring time of the stirrer is 20-30 min, and in B2, the ultrasonic treatment time is 20-30 min.

[0026] In a preferred embodiment of the present invention, the wall thickness of the microcapsule is 50-150 um, and the diameter ranges from 400 um to 800 um.

[0027] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0028] (1) The present invention provides a method for preparing a metal surface nano-coating for metal processing. The use of a microcapsule filler significantly enhances the adhesion between the metal surface and the nano-coating. After the microcapsule filler is filled in the porous structure formed by laser processing on the metal surface, the microcapsules rupture and release the contents during the heating process and fill into the porous structure, which not only fills the microscopic unevenness of the metal surface, but also increases the physical and chemical bonding force between the metal surface and the nano-coating due to its unique material properties. Therefore, the nano-coating can be more closely attached to the metal surface to form a more solid and durable coating structure. The use of the microcapsule filler not only improves the protective performance of the metal surface, but also prolongs the service life of the metal, reduces the maintenance cost, and brings significant economic and environmental benefits to the metal processing industry.

[0029] (2) In the present invention, during the heat treatment, the shell material of the microcapsule is broken due to the increase in temperature, releasing the internal filler. At the same time, the broken shell material of the microcapsule can be efficiently combined with the dispersant in the nano coating solution, which not only achieves the close combination of the microcapsule shell material and the nano coating, but also enhances the adhesion between the nano coating and the metal substrate. Through the efficient combination, the nano coating can be more firmly attached to the surface of the metal part to form a stable and durable protective layer, which not only improves the corrosion resistance, wear resistance and scratch resistance of the metal part, but also ensures the stability and durability of the coating in various complex environments. In addition, due to the close combination of the nano coating and the metal surface, the risk of peeling or cracking of the coating during use is also reduced, further improving the service life and reliability of the metal part.

[0030] (3) In the present invention, a micron-scale multi-elliptical pore structure is formed on the metal surface by laser processing, and microcapsule contents composed of thermosetting resin are filled, and then a nano coating is applied. This method significantly enhances the corrosion resistance of the metal surface. The nanomaterials in the nano coating, especially nano titanium dioxide, can effectively resist the penetration of moisture, oxygen and other corrosive substances, and the heating expansion effect of the microcapsule contents further enhances the sealing and protective capabilities of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a schematic diagram of a method for preparing a metal surface nano-coating according to a preferred embodiment of the present invention;

[0033] Figure 2 Schematic diagram of a method for preparing a microcapsule filler according to a preferred embodiment of the present invention;

[0034] Figure 3 It is a schematic diagram of a method for preparing a nano coating solution according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0037] like Figure 1 As shown, a method for preparing a metal surface nano coating for metal processing comprises the following steps:

[0038] S1: Laser processing the surface of a metal part to form a number of micrometer-level elliptical hole structures;

[0039] S2: coating the microcapsule filler on the surface of the porous metal part;

[0040] S3: After the microcapsule filler is dried, the nanocoating solution is applied, and the drying time is 0.5-1h;

[0041] S4: heating the coated metal part at a temperature of 80-100°C for a time of 20-40 minutes to rupture the microcapsules and release the contents to fill the porous structure;

[0042] S5: Cool the metal part for 1-2 hours to solidify the filling layer.

[0043] It should be noted that during laser processing, femtosecond laser drilling technology is used, the laser power range is 80-200mW, the pulse frequency is 200-800kHz, the scanning speed is 1-15mm / s, and a number of micron-level multi-elliptical hole structures with a depth of 5-10um and an aperture range of 5-20um are processed on the surface of the metal part, providing a good attachment point for subsequent coating treatment. The microcapsule filler is filled in the tiny elliptical pores on the metal surface. The thickness of the microcapsule filler is in the range of 5-20um, and during the heating process, the microcapsules rupture and release the contents, further filling and The porous structure is reinforced, greatly enhancing the density and uniformity of the metal surface. After the microcapsule filler is dried, the nano-coating solution is applied with a coating thickness ranging from 15-40um and a drying time of 0.5-1h. The nano-titanium dioxide in the nano-coating has excellent corrosion resistance, wear resistance and scratch resistance, which effectively enhances the protective performance of metal parts. During the heating process, the microcapsule shell material and the dispersant in the nano-coating solution are efficiently combined to further enhance the adhesion between the coating and the metal surface, ensuring the adhesion of the coating during long-term use. Finally, the filling layer is solidified through cooling treatment, and the entire coating structure is more stable.

[0044] like Figure 2 As shown, the preparation method of the microcapsule filler comprises the following steps:

[0045] A1: Select a thermosetting resin with heating expansion effect as the content of the microcapsule;

[0046] A2: Select polyurethane that efficiently combines with the dispersant in the nano-coating solution as the shell material of the microcapsules;

[0047] A3: Using emulsification technology, the selected inclusions are encapsulated inside the microcapsules formed by the shell material to prepare microcapsule fillers. The mass ratio of the inclusions to the shell material is 30:70-70:30, the wall thickness of the microcapsule is 50-150um, and the diameter ranges from 400um to 800um.

[0048] It should be noted that metal parts include alloy steel, nickel alloy, titanium alloy, zinc alloy, etc. During the preparation process, the existing emulsification technology is used to enable the contents to be evenly wrapped inside the shell material to form a structurally stable microcapsule. When the microcapsule filler is coated on the surface of the metal part and subjected to heat treatment, the heating expansion effect of the contents makes the filling tighter and enhances the smoothness and integrity of the metal surface. The polyurethane shell material is efficiently combined with the dispersant in the nano-coating solution, which not only improves the adhesion of the coating, but also enhances the adhesion and uniformity of the coating.

[0049] like Figure 3 As shown, the nano coating solution includes: nano material: 5-15% nano titanium dioxide; solvent: 70-90% ethanol; dispersant: 0.1-5% polyvinyl pyrrolidone; stabilizer: 0.1-5% silane coupling agent; additive: 1-10% corrosion resistant agent.

[0050] The method for preparing a nano coating solution comprises the following steps:

[0051] B1: Mix the solvent, dispersant, stabilizer and additives evenly, then add the nanomaterials and continue stirring with a stirrer for 20-30 minutes until the nano coating solution is completely dispersed;

[0052] B2: While stirring, use an ultrasonic disperser to ultrasonically treat the nano-coating solution for 20-30 minutes.

[0053] It should be noted that a highly uniform and stable nano-coating solution is obtained by accurately proportioning nano-titanium dioxide, ethanol, polyvinyl pyrrolidone, silane coupling agent and corrosion inhibitor. Nano-titanium dioxide, as the main nano-material, provides excellent protection for the coating with its excellent corrosion resistance and wear resistance. In the preparation process of the nano-coating solution, it is ensured that the various components in the solution can be fully mixed to avoid agglomeration and precipitation of the nano-materials. The solution is ultrasonically treated by an ultrasonic disperser so that the nano-materials are more evenly dispersed in the solution, thereby improving the uniformity and consistency of the coating.

[0054] The nano-coating solution can be evenly coated on the surface of metal parts to form a dense and uniform protective layer. It not only has excellent corrosion resistance and wear resistance, but also can resist ultraviolet radiation and oxidative corrosion, thereby significantly extending the service life of metal parts. In addition, the nano-coating also has good adhesion and coating uniformity, can adhere tightly to the surface of metal parts, and is not easy to peel off or crack.

[0055] Embodiment 1:

[0056] The preparation of the nano coating solution comprises the following steps:

[0057] B1: Mix 80% ethanol, 2.5% polyvinyl pyrrolidone, 2.5% silane coupling agent and 5% corrosion inhibitor evenly, then add 10% nano titanium dioxide and continue stirring with a stirrer for 25 minutes until the nano coating solution is completely dispersed;

[0058] B2: While stirring, the nanocoating solution was ultrasonically treated using an ultrasonic disperser for 25 min.

[0059] To prepare the microcapsule filler, the mass ratio of thermosetting resin to polyurethane is 50:50, and the polyamide resin is uniformly wrapped inside the polyurethane shell using the emulsification method to form microcapsules. The wall thickness of the microcapsule is controlled at 100um and the diameter range is 600um.

[0060] Preparation method of metal surface coating:

[0061] S1: Use a femtosecond laser to process the alloy steel surface. Set the laser power to 120mW, the pulse frequency to 400kHz, and the scanning speed to 10mm / s. Process several micrometer-level elliptical hole structures on the alloy steel surface. The hole depth is 5um and the hole diameter is 12um.

[0062] S2: The microcapsule filler is evenly coated on the surface of the laser-processed porous alloy steel with a coating thickness of 10 μm to ensure that the microcapsules can fully fill the tiny elliptical pores;

[0063] S3: After the microcapsule filler coating is dry, the drying time is 30 minutes, and the nano coating solution is evenly coated on the surface of the alloy steel by spraying. The coating thickness is within 20um, ensuring that the coating is uniform and fully covered. The coated alloy steel is placed in a dry environment to allow the nano coating solution to dry completely within 1 hour.

[0064] S4: After drying, the coated alloy steel surface is heated with a hot air gun to 90°C and maintained for 30 minutes to rupture the microcapsules and release the contents to fill the porous structure.

[0065] S5: The alloy steel after the heating treatment is naturally cooled to room temperature for 1.5 hours to solidify the filling layer.

[0066] Embodiment 2:

[0067] This embodiment is basically the same as the first embodiment, except that step S2 is deleted, and in step S3, the microcapsule filler is removed, and the nano-coating solution is directly applied to the laser-processed alloy steel surface to ensure that the nano-coating solution fully fills the gaps of several micron-sized elliptical pores.

[0068] Embodiment three:

[0069] This embodiment is basically the same as the first embodiment, except that in step S1, a femtosecond laser is used to perform laser processing on the surface of the alloy steel, the laser power is set to 120 mW, the pulse frequency is 400 kHz, and the scanning speed is 10 mm / s, and a number of micron-scale circular hole structures are processed on the surface of the alloy steel. The micron-scale circular hole has a depth of 5 um and a hole diameter of 12 um.

[0070] Embodiment 4:

[0071] This embodiment is basically the same as the third embodiment, except that step S2 is deleted, and in step S3, the microcapsule filler is removed, and the nano-coating solution is directly applied to the laser-processed alloy steel surface to ensure that the nano-coating solution fully fills the gaps of several micron-sized circular holes.

[0072] Below is an example of an experimental table comparing several micron-sized elliptical holes and several micron-sized circular holes on an alloy steel surface, with and without a microcapsule filler between the nanocoating solution and the alloy steel surface, for adhesion, coating uniformity, and corrosion resistance.

[0073] Table 1:

[0074] Adhesion test: Fix the specimen on a tensile testing machine, apply tensile force until the coating separates from the metal substrate, and record the maximum tensile force value.

[0075] Coating uniformity test: Use a scanning electron microscope to observe the coating surface and evaluate whether the coating is uniform and free of defects such as bubbles and cracks.

[0076]

[0077] Adhesion: Indicates that the adhesion between the nano coating solution and the alloy steel surface is stronger. From the table, it can be seen that both the elliptical holes and the circular holes with microcapsule fillers have higher adhesion than the holes without microcapsule fillers, among which the elliptical holes perform best with microcapsule fillers.

[0078] Coating Solution Uniformity: A higher score indicates a more uniform distribution of the nanocoating solution. Similarly, both oval and circular wells with microencapsulated fillers had higher nanocoating solution uniformity scores than wells without microencapsulated fillers. Oval wells performed best with microencapsulated fillers.

[0079] Table 2:

[0080] Wear resistance test: Nano coating was applied on alloy steel (with micron-sized oval and circular holes), and microcapsule filler was partially added; the test pieces were exposed in a salt spray test chamber (5% sodium chloride solution, 35°C and saturated humidity), and their corrosion conditions (flaking, rusting, discoloration) were observed and recorded; the corrosion resistance of the coating was evaluated according to the degree of corrosion, and a rating system was used to quantify the score.

[0081]

[0082]

[0083] Corrosion resistance: When applying nanocoatings on elliptical holes and circular holes, the use of microcapsule fillers can improve the adhesion, coating uniformity, corrosion resistance and wear resistance of the coatings; under the same experimental conditions, the nanocoatings on elliptical holes (regardless of whether microcapsule fillers are used) are generally superior to those on circular holes in terms of adhesion, coating uniformity, corrosion resistance and wear resistance.

[0084] It can be seen from Tables 1 and 2 that, whether it is an elliptical hole or a circular hole, the adhesion of the nanocoating solution, the uniformity of the nanocoating solution, the corrosion resistance and the wear resistance are all improved when the microcapsule filler is used.

[0085] Among them, the elliptical holes have the best performance in all aspects when there is a microcapsule filler.

[0086] Because the oval shape provides a larger adjustment space and a closer contact, it is beneficial to the distribution of microcapsule fillers and the formation of nano-coating solution.

[0087] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a metal surface nano coating for metal processing, characterized in that: The following steps are involved: S1: Laser processing the surface of a metal part to form a number of micrometer-level elliptical hole structures; S2: coating the microcapsule filler on the surface of the porous metal part; S3: After the microcapsule filler is dried, the nanocoating solution is applied, and the drying time is 0.5-1h; S4: heating the coated metal part to rupture the microcapsules and release the contents to fill the porous structure; S5: Cool the metal part for 1-2 hours to solidify the filling layer.

2. The method for preparing a metal surface nano coating for metal processing according to claim 1, characterized in that: The preparation method of the microcapsule filler comprises the following steps: A1: Select thermosetting resin as the content of microcapsules; A2: Choose polyurethane as the shell material of microcapsules; A3: The microcapsule filler is prepared by encapsulating the selected contents inside the microcapsules formed by the shell material using the emulsification technology.

3. The method for preparing a metal surface nano coating for metal processing according to claim 1, characterized in that: The nano coating solution comprises: nano material: 5-15% of nano titanium dioxide; solvent: 70-90% of ethanol; dispersant: 0.1-5% of polyvinyl pyrrolidone; stabilizer: 0.1-5% of silane coupling agent; additive: 1-10% of corrosion resistance agent.

4. The method for preparing a metal surface nano coating for metal processing according to claim 3, characterized in that: The method for preparing the nano coating solution comprises the following steps: B1: Mix the solvent, dispersant, stabilizer and additives evenly, then add the nanomaterials and continue stirring with a stirrer until the nano coating solution is completely dispersed; B2: The nanocoating solution was sonicated using an ultrasonic disperser while stirring.

5. The method for preparing a metal surface nano coating for metal processing according to claim 1, characterized in that: In the step S4, the heating temperature of the heating treatment is 80-100°C, and the heating time is 20-40 minutes.

6. The method for preparing a metal surface nano coating for metal processing according to claim 2, characterized in that: In the above-mentioned A1, the above-mentioned thermosetting resin has a heating expansion effect.

7. The method for preparing a metal surface nano coating for metal processing according to claim 2, characterized in that: In A2, the shell material of the microcapsule is efficiently combined with the dispersant in the nanocoating solution.

8. The method for preparing a metal surface nano coating for metal processing according to claim 2, characterized in that: The mass ratio of the inner material to the outer shell material is 30:70-70:

30.

9. The method for preparing a metal surface nano coating for metal processing according to claim 4, characterized in that: In the B1, the stirring time of the stirrer is 20-30 min, and in the B2, the ultrasonic treatment time is 20-30 min.

10. The method for preparing a metal surface nano coating for metal processing according to claim 2, characterized in that: The wall thickness of the microcapsule is 50-150um, and the diameter ranges from 400um to 800um.

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