Blade surface treatment method

Abstract

According to the blade surface treatment method provided by the invention, 1, 3-bis (chloromethyl) tetramethyldisilazane is adopted as a liquid A for forming a base film, on one hand, the liquid A can form a stable covalent bond with the blade, and on the other hand, the active chloromethyl end of the liquid A can provide rich reaction sites for a honeycomb film layer, so that chemical bonding of the film layer is promoted, and the service life of the blade is prolonged; carbonizable polyvinylpyrrolidone and hexadecyl trimethyl ammonium bromide are adopted as template agents, a compact hierarchical pore structure can be provided, a carbon-silicon composite structure can be formed, a mixture of perhydropolysilazane and polyhedral oligomeric silsesquioxane is adopted before final film forming, and the brittleness defect of pure SiO2 can be fully overcome; and the prepared coating is high in stability and strong in adhesive force, and can meet the requirements of high-end fields or precise high-speed numerical control equipment tool bits.

Description

Technical Field

[0001] This invention belongs to the technical field of metal surface treatment, and specifically relates to a method for surface treatment of blades. Background Technology

[0002] To improve the corrosion resistance and wear resistance of cutting tools, they need to be coated after forging and heat treatment. Commonly used methods include physical vapor deposition (PVD), chemical vapor deposition (CVD), and electroplating. For high-precision CNC lathe milling cutters, aerospace utility knives, and other high-end tools, the most mature method is PVD coating with TiN. Although this method produces stable and high-strength coatings, it requires significant investment in plasma equipment, is difficult to control coating consistency, and demands extremely high equipment precision. Furthermore, adjusting equipment parameters is difficult when new series are launched, resulting in numerous trial production batches and significant product waste. Therefore, developing a simpler, more controllable alternative to PVD coating is an urgent problem to be solved in this industry.

[0003] Honeycomb structure coatings possess significant corrosion resistance and physical properties, making them widely used in coatings for building exteriors and industrial equipment, significantly extending product lifespan. However, their application in high-end precision cutting tools is less frequently reported. This is primarily because the adhesion of physically coated coatings for precision tools is far less than that of vapor-deposited coatings. In high-speed cutting or high-precision industries, coating peeling can lead to serious quality problems and even safety accidents. Therefore, improving the adhesion of cutting tool coatings is a key research direction for driving products towards the high-end market. Summary of the Invention

[0004] To address the aforementioned issues, this invention develops a surface treatment method that replaces physical vapor deposition (PVD). The coating prepared by this method exhibits strong adhesion, and the process is simple and controllable, meeting the requirements of high-end precision cutting tools.

[0005] The specific solution of the present invention is as follows: the blade after heat treatment and grinding is first immersed in liquid A for 15-20 minutes under a low temperature nitrogen atmosphere of -15℃ to -10℃, and then vacuum dried at 5-15℃ to form an anti-oxidation layer. Then it is immersed in liquid B and gradually dried to form a dense honeycomb wear-resistant layer with dense pore walls.

[0006] Solution A is 1,3-bis(chloromethyl)tetramethyldisilazane.

[0007] Specifically, the B-liquid impregnation treatment is as follows: After the blade has been impregnated and dried by the A-liquid, it is first impregnated at room temperature in an iron-based phosphating solution for 3-5 minutes, then drained and impregnated in an ethanol aqueous solution containing 40%-45% by mass of polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 5-10 minutes. After removal, while still wet, it is impregnated in a mixture of perhydropolysilazane and cage-type silsesquioxane in a molar ratio of 1:1 for 5-10 minutes. During the impregnation process, the blade is rolled at 50 rpm along the transverse axis.

[0008] The gradient drying process involves first vacuum drying at 75-85℃ for 5±1 min, then raising the temperature to 250-270℃ and continuing drying for 10-15 min to form a stable and dense honeycomb wear-resistant layer.

[0009] The polyvinylpyrrolidone content is 5-8 g / L; the cetyltrimethylammonium bromide content is 50-55 g / L.

[0010] Among them, the cage-type silsesquioxane is preferably one of cyclohexylPOSS, isooctylPOSS, and cyclopentylPOSS.

[0011] Specifically, the mixture of perhydropolysilazane and cage-type silsesquioxane is prepared by adding POSS solid powder to PHPS liquid under inert gas protection and stirring at 25℃-30℃ until completely dissolved.

[0012] The beneficial effects of this invention are: 1. This invention adopts a multi-stage impregnation film formation method to build a stable chemical bond film formation principle. The process is simple and the film formation is easy to control. Moreover, the film formation cycle is short and the consistency is high. The adhesion of the film layer is ensured by the formation of stable covalent bonds between the substrates. Combined with the control of the process, the film layer has a honeycomb structure, high corrosion resistance and good physical properties.

[0013] 2. The A solution used for base film formation is 1,3-bis(chloromethyl)tetramethyldisilazane. It can not only form strong Si-OM covalent bonds on the metal surface and improve the adhesion of the A layer, but also its chloromethyl end has high reactivity. It can not only self-crosslink, but also provide abundant reaction sites for the subsequent B layer of the honeycomb film, realize the chemical bonding of the film layer and enhance the stability of the film layer.

[0014] 3. The template agent B solution used in the B layer is a mixture of polyvinylpyrrolidone and cetyltrimethylammonium bromide at a specific concentration. On the one hand, at this concentration, the two work synergistically to form a hierarchical porous structure with a dual-pore size distribution, which is more conducive to improving toughness. On the other hand, during the heat treatment process to form a honeycomb coating, polyvinylpyrrolidone can be partially carbonized and form a carbon-silicon composite structure, which further improves the stability of the film. Moreover, the template agent can be removed at a lower temperature to form a dense network structure, avoiding the influence of high temperature on the tempering hardness of the blade metal.

[0015] 4. Before final film formation, all-hydrogen polysilazane is used, which can be converted into high-purity, amorphous SiO2 at a relatively low temperature. It has good density and complements the organic-inorganic hybrid characteristics of cage-type silsesquioxane. Furthermore, cage-type silsesquioxane can act as "nano-bricks" to greatly enhance the hardness, toughness, and thermal stability of the SiO2 network. The combination of the two results in a composite honeycomb layer that is both hard and has a certain degree of toughness and excellent heat resistance, perfectly overcoming the brittleness of pure SiO2.

[0016] 5. Before the B layer is formed, a phosphating solution is used to treat it. The purpose is to use the phosphating reaction to rapidly generate irregular micron / nano-sized iron phosphate crystal particles on the surface of the A layer. These particles serve as heterogeneous nucleation sites, providing a huge specific surface area and abundant nucleation sites for the subsequent micelle assembly of the template agent and the hydrolysis and condensation of the silica precursor. This method can form a composite wear-resistant structure in which a "mesoporous honeycomb structure" and "micron-sized phosphating protrusions" are nested together. The phosphating grains bear the main impact load, while the mesoporous SiO2 network provides fine wear resistance, achieving "macro-micro" dual protection. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the embodiments.

[0018] The raw materials used in the embodiments of this application are all commercially available generic types. 1,3-bis(chloromethyl)tetramethyldisilazane was purchased from Sichuan Kulinan Technology Co., Ltd., and perhydropolysilazane was purchased from Kemaidi 122174-44-1.

[0019] Example 1 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -13℃, and then vacuum dried at 8℃ to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 4 minutes, drained, and then impregnated with an ethanol aqueous solution containing 40% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 5 minutes. The polyvinylpyrrolidone content is 5 g / L, and the hexadecyltrimethylammonium bromide content is 55 g / L. 2. Under nitrogen protection, add cyclohexyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 25°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 8 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 80℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 13 min to obtain a coating thickness of 3.3±0.2μm.

[0020] Example 2 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 20 minutes under a nitrogen atmosphere at -15°C, and then vacuum dried at 15°C to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 3 minutes, drained, and then impregnated with an ethanol aqueous solution containing 45% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 10 minutes. The polyvinylpyrrolidone content is 8 g / L, and the hexadecyltrimethylammonium bromide content is 50 g / L. 2. Under nitrogen protection, add isooctyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 30°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 75°C for 5±1 min, and then the temperature is raised to 270°C and dried for another 10 min to obtain a coating thickness of 3.8±0.2 μm.

[0021] Example 3 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -10℃, and then vacuum dried at 5℃ to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 5 minutes, drained, and then impregnated with an ethanol aqueous solution containing 40% (w / w) polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 5 minutes. The polyvinylpyrrolidone content is 6.5 g / L, and the hexadecyltrimethylammonium bromide content is 53 g / L. 2. Under nitrogen protection, cyclopentyl POSS solid powder was added to perhydropolysilazane at a molar ratio of 1:1 and stirred at 30°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 5 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 85℃ for 5±1 min, and then the temperature is raised to 250℃ and dried for another 15 min to obtain a coating thickness of 2.6±0.1 μm.

[0022] Comparative Example 1 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,1,3,3-tetramethyldisilazane for 20 minutes under a nitrogen atmosphere at -15°C, and then vacuum dried at 10°C to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 5 minutes, drained, and then impregnated with an ethanol aqueous solution containing 45% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 10 minutes. The polyvinylpyrrolidone content is 7 g / L, and the hexadecyltrimethylammonium bromide content is 50 g / L. 2. Under nitrogen protection, add cyclohexyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 25℃-30℃ until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 85℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 15 min to obtain a coating thickness of 4.1±0.6μm.

[0023] Comparative Example 2 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -15°C, and then vacuum dried at 8°C to form an anti-oxidation layer. Next, they are impregnated in an ethanol-water solution containing 40% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide (mass fraction) for 5 minutes. The polyvinylpyrrolidone content is 8 g / L, and the hexadecyltrimethylammonium bromide content is 55 g / L. 2. Under nitrogen protection, add cyclohexyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 25°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 80℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 13 min to obtain a coating thickness of 3.5±0.4μm.

[0024] Comparative Example 3 1. After heat treatment and grinding, the cutting tool is first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -13℃, and then vacuum dried at 8℃ to form an anti-oxidation layer. After that, it is impregnated with an iron-based phosphating solution at room temperature for 4 minutes, drained, and then impregnated with an ethanol aqueous solution containing 40% polyvinylpyrrolidone (PVP) for 5 minutes. The PPV content is 8 g / L. 2. Under nitrogen protection, add cyclohexyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 25°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 75℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 13 min to obtain a coating thickness of 3.6±0.3μm.

[0025] Comparative Example 4 1. After heat treatment and grinding, the cutting tool is first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -13℃, and then vacuum dried at 8℃ to form an anti-oxidation layer. After that, it is impregnated with an iron-based phosphating solution at room temperature for 4 minutes, drained, and then impregnated with an ethanol aqueous solution containing 40% hexadecyltrimethylammonium bromide for 5 minutes. The hexadecyltrimethylammonium bromide content is 55 g / L. 2. Under nitrogen protection, add cyclohexyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 25°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 8 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 80℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 10 min to obtain a coating thickness of 3.1±0.3μm.

[0026] Comparative Example 5 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 15 minutes under a nitrogen atmosphere at -10℃, and then vacuum dried at 8℃ to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 5 minutes, drained, and then impregnated with an ethanol aqueous solution containing 40% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 5 minutes. The polyvinylpyrrolidone content is 5 g / L, and the hexadecyltrimethylammonium bromide content is 50 g / L. 2. Remove the blade treated in step 1 and immerse it in perhydropolysilazane while it is still wet for 8 minutes; 3. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 2 is taken out and vacuum dried at 80℃ for 5±1 min, and then the temperature is raised to 260℃ and dried for another 13 min to obtain a coating thickness of 3.1±0.7μm.

[0027] Comparative Example 6 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 20 minutes under a nitrogen atmosphere at -10℃, and then vacuum dried at 15℃ to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 5 minutes, drained, and then impregnated with an ethanol aqueous solution containing 45% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 10 minutes. The polyvinylpyrrolidone content is 8 g / L, and the hexadecyltrimethylammonium bromide content is 50 g / L. 2. Add cyclohexyl POSS solid powder to toluene solution at a weight-volume ratio of 1g:50ml, and stir at 30℃ until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and vacuum dried at 85℃ for 5±1 min, and then the temperature is raised to 270℃ and dried for another 15 min to obtain a coating thickness of 2.8±0.8μm.

[0028] Comparative Example 7 1. After heat treatment and grinding, the cutting tools are first impregnated with 1,3-bis(chloromethyl)tetramethyldisilazane for 20 minutes under a nitrogen atmosphere at -15°C, and then vacuum dried at 15°C to form an anti-oxidation layer. After that, they are impregnated with an iron-based phosphating solution at room temperature for 3 minutes, drained, and then impregnated with an ethanol aqueous solution containing 45% polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 10 minutes. The polyvinylpyrrolidone content is 56 g / L, and the hexadecyltrimethylammonium bromide content is 52 g / L. 2. Under nitrogen protection, add isooctyl POSS solid powder to perhydropolysilazane at a molar ratio of 1:1 and stir at 30°C until completely dissolved; 3. Remove the blade treated in step 1 and, while still wet, immerse it in the mixture from step 2 for 10 minutes; 4. During the impregnation process, the blade is rotated at 50 rpm along the horizontal axis; then the blade treated in step 3 is taken out and heated to 270℃ and dried for 10 min to obtain a coating thickness of 3.6±0.6μm.

[0029] Experiments: The hardness, adhesion, and wear resistance of the above-mentioned films were tested respectively. The control group used the company's chrome-plated blade. The test results are shown in the table below. The hardness was tested using the Vickers microhardness test, with an indenter load of 1000 gf and calibration coefficients: X: 0.315240 um / pix; Y: 0.321271 um / pix; the holding time was 10s, and 5 groups of test samples were used for each test. The adhesion was tested using the scratch test method. The wear resistance was tested using the MMU-10G high-temperature friction and wear tester at temperatures of 400℃ and 700℃.

[0030]

Claims

1. A method for surface treatment of a blade, characterized in that: After heat treatment and grinding, the cutting tools are first immersed in solution A for 15-20 minutes under a low-temperature nitrogen atmosphere of -15℃ to -10℃, and then vacuum dried at 5-15℃ to form an anti-oxidation layer. Then, they are immersed in solution B and dried in a gradient manner.

2. The blade surface treatment method as described in claim 1, characterized in that: The A solution is 1,3-bis(chloromethyl)tetramethyldisilazane.

3. The blade surface treatment method as described in claim 1, characterized in that: The B-liquid impregnation treatment is specifically as follows: After the blade has been impregnated and dried by the A-liquid, it is first impregnated at room temperature in an iron-based phosphating solution for 3-5 minutes, then drained and impregnated in an ethanol aqueous solution containing 40%-45% by mass of polyvinylpyrrolidone and hexadecyltrimethylammonium bromide for 5-10 minutes. After removal, while still wet, it is impregnated in a mixture of perhydropolysilazane and cage-type silsesquioxane in a molar ratio of 1:1 for 5-10 minutes. During the impregnation process, the blade is rolled at 50 rpm along the transverse axis.

4. The blade surface treatment method as described in claim 1, characterized in that: The gradient drying process involves first vacuum drying at 75-85℃ for 5±1 minutes, then raising the temperature to 250-270℃ and continuing drying for 10-15 minutes.

5. The blade surface treatment method as described in claim 3, characterized in that: The content of polyvinylpyrrolidone is 5-8 g / L; the content of hexadecyltrimethylammonium bromide is 50-55 g / L.

6. The blade surface treatment method as described in claim 3, characterized in that: The cage-like silsesquioxane is one of cyclohexylPOSS, isooctylPOSS, and cyclopentylPOSS.

7. The blade surface treatment method as described in claim 3, characterized in that: The mixture of perhydropolysilazane and cage-type silsesquioxane is specifically prepared by adding POSS solid powder to PHPS liquid under inert gas protection and stirring at 25℃-30℃ until completely dissolved.

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