Polishing composition and polishing solution for fine polishing of aluminum alloy surface and application of polishing composition and polishing solution

Abstract

The invention discloses a polishing composition and a polishing solution for fine polishing of an aluminum alloy surface and application of the polishing composition and the polishing solution, and particularly belongs to the technical field of metal surface treatment. The polishing composition comprises the following components in parts by mass: 70-80 parts of silica sol, 1-4 parts of a dispersing agent, 5-7 parts of a surfactant, 5-10 parts of a corrosion inhibitor and 0.5-2 parts of a water-retaining agent, the surfactant is prepared from perfluoropolyether, coconut oil alkanolamide and sodium dodecyl benzene sulfonate. The polishing composition is high in polishing efficiency, the polishing cost can be reduced, the product quality can be improved, the surface roughness of a material obtained after polishing treatment is low, the number of scratches is small, the quality of the polished surface is effectively improved, the overall attractiveness and durability of the material are improved, the polishing solution does not contain toxic substances such as chromium / phosphorus, and environment friendliness is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal surface treatment, and in particular relates to a polishing composition for fine polishing of aluminum alloy surfaces, a polishing liquid and applications thereof. Background Art

[0002] Aluminum alloys are widely used in consumer electronics, automotive parts, aerospace, and high-end decoration due to their excellent strength-to-weight ratio, thermal conductivity, and processing properties. In these applications, high surface finish, high reflectivity, and flawless polishing are key requirements for enhancing product aesthetics, corrosion resistance, and functionality.

[0003] At present, the industry mainly relies on the following two types of technologies for fine polishing of aluminum alloy surfaces:

[0004] 1. Traditional chemical / electrochemical polishing:

[0005] Strong oxidizing acid systems such as phosphoric acid, nitric acid, and chromic acid are used. Although a bright surface can be achieved, this method carries the risk of severe environmental pollution (phosphorus / chromium wastewater), high corrosion risk (prone to pitting and intergranular corrosion), and operational hazards, making it difficult to meet increasingly stringent environmental regulations.

[0006] 2. Mechanical grinding and polishing fluid containing abrasives:

[0007] Silica sol, aluminum oxide, etc. are used as abrasives, supplemented by additives. Although environmental protection has been improved, existing polishing fluids still have significant defects: Insufficient corrosion inhibition: In alkaline polishing environments (pH is often greater than 10), aluminum alloy surfaces are prone to uneven corrosion, loss of gloss, and even black spots, especially for high-performance alloys containing copper and zinc. Poor abrasive dispersion stability: Nano-SiO2 particles are prone to agglomeration and sedimentation, resulting in a short storage period of the polishing fluid and uneven distribution of abrasives during the polishing process, causing surface defects such as scratches and orange peel patterns. Unbalanced surfactant compatibility: Single or simply compounded surfactants are difficult to take into account wetting and penetration, oil emulsification, foam control, and abrasive dispersion synergy, resulting in fluctuations in polishing efficiency or residual stains.

[0008] While recent research has attempted to develop environmentally friendly polishing fluids, these efforts have largely focused on optimizing a single component, failing to systematically address the multi-dimensional contradictions between abrasive dispersion stability, corrosion inhibition efficiency, and surface activity synergy. In high-end manufacturing, in particular, there is an urgent need for a polishing technology that simultaneously achieves "zero corrosion damage, super-mirror gloss, and long-term stability." Summary of the Invention

[0009] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a new polishing composition and polishing liquid for fine polishing of aluminum alloys. Through multi-component functional coupling and ratio innovation, it solves the problems of insufficient corrosion inhibition performance and poor abrasive dispersion stability while reducing pollution.

[0010] In order to achieve the above object, the present invention discloses the following technical solutions:

[0011] In a first aspect, the present invention provides a polishing composition for fine polishing of aluminum alloy surfaces, wherein the composition comprises the following components in parts by mass:

[0012]

[0013] The surfactant consists of perfluoropolyether, coconut oil alkanolamide and sodium dodecylbenzenesulfonate.

[0014] Preferably, the mass percentage of silicon dioxide in the silica sol is 30-45%.

[0015] More preferably, the silicon dioxide is silicon dioxide particles with a particle size of 50-100 nm.

[0016] Preferably, the dispersant is selected from at least one of polyethylene glycol, sodium polyacrylate, and polyvinyl pyrrolidone.

[0017] Preferably, the surfactant is composed of perfluoropolyether, coconut oil alkanolamide, and sodium dodecylbenzenesulfonate in a mass ratio of 1: (1-2): (0.6-0.8).

[0018] Preferably, the corrosion inhibitor is composed of copolyvidone and ammonium persulfate in a mass ratio of 1:(0.3-0.5).

[0019] Further preferably, the preparation method of the corrosion inhibitor comprises the following steps:

[0020] (1) Deionized water was heated to 50±5°C, and copolyvidone powder was added according to a solid-liquid mass ratio of 1:(8-10), and the mixture was stirred at 200-300 rpm for 30-40 minutes. After dissolution was completed, the system was cooled to 25-30°C to obtain a copolyvidone solution;

[0021] (2) dissolving ammonium persulfate in deionized water at a solid-liquid mass ratio of 1:(5-7) at 20-30° C., and stirring at 100-150 rpm until a transparent solution is obtained to obtain an ammonium persulfate solution;

[0022] (3) The ammonium persulfate solution was added dropwise to the copolyvidone solution at a rate of 5 mL / min, and the mixture was stirred at 300 rpm and kept in a water bath at 30±2°C. After the addition was completed, the stirring was continued for 60 min to obtain a corrosion inhibitor. The amount of the added solution was converted according to the mass ratio of copolyvidone to ammonium persulfate of 1:(0.3-0.5).

[0023] Preferably, the water-retaining agent is at least one of butylene glycol, glycerol and hexylene glycol.

[0024] In a second aspect, the present invention provides a polishing liquid for fine polishing of aluminum alloy surfaces, wherein the polishing liquid contains the polishing composition described in the first aspect.

[0025] Preferably, the polishing liquid further contains water.

[0026] Further preferably, the polishing liquid contains the following components in parts by mass:

[0027]

[0028] In a third aspect, the present invention provides a method for preparing the polishing liquid according to the second aspect, the preparation method comprising the following steps:

[0029] Step 1. Place silica sol, surfactant, water-retaining agent and water in a mixing container and mix and stir evenly to obtain mixture A;

[0030] Step 2. Stirring the mixture A at a speed of 200-300 r / min, adding a dispersant and a corrosion inhibitor while stirring, and stirring for 40-50 minutes to obtain the polishing liquid.

[0031] In a fourth aspect, the present invention provides use of the polishing composition described in the first aspect in preparing a polishing preparation for aluminum alloy.

[0032] In the present invention:

[0033] The surfactant can improve the wettability of the polishing liquid on the aluminum alloy surface, ensuring that the liquid can evenly spread and cover the entire polishing surface, avoiding uneven polishing. At the same time, it emulsifies tiny oil stains or organic residues to prevent them from depositing on the surface and causing polishing defects, scratches, pitting, etc. The surfactant provided by the present invention can assist the dispersant in stabilizing silica nanoparticles and prevent abrasive agglomeration and sedimentation. Perfluoropolyether, coconut oil alkanolamide and sodium dodecylbenzene sulfonate jointly maintain wettability, emulsification and dispersibility within the specific ratio range provided by the present invention.

[0034] As a water-soluble high molecular polymer, copolyvidone has excellent adsorption and film-forming ability on the metal surface. It can form a physical barrier film to isolate the corrosive medium from contact with the aluminum matrix, thereby achieving corrosion inhibition. At the same time, its molecular structure contains groups that can complex with metal ions, enhancing the protective effect and also playing a certain role in dispersion and stabilization.

[0035] As an oxidizing salt, ammonium persulfate's oxidizing action helps form a dense, stable, and easily mechanically strippable soft passivation oxide film on the aluminum surface, significantly improving polishing efficiency and enhancing the aluminum's corrosion resistance. However, too little oxidant can lead to excessive mechanical action, which can cause scratches on the wafer surface. Too much oxidant can lead to excessively high surface chemical potential, allowing the surface to enter the corrosion zone and cause defects such as surface corrosion pits. Therefore, the present invention optimizes the polishing effect and surface quality of the formula by controlling the concentration and ratio of copolyvidone and the oxidant.

[0036] Beneficial effects of the present invention:

[0037] 1. The present invention improves the fine polishing performance of aluminum alloys through an innovative synergistic system of surfactants and corrosion inhibitors. Perfluoropolyether, coconut oil alkanolamide and sodium dodecylbenzene sulfonate in the surfactant are compounded in a specific proportion to synergistically solve the problems of abrasive agglomeration, uneven wetting and unstable dispersion, thereby reducing the surface roughness after polishing, reducing scratch defects, and extending the suspension stability. The corrosion inhibitor forms a dynamic protective layer, which improves the polishing efficiency while achieving polishing uniformity, further reducing the surface roughness after polishing.

[0038] 2. The polishing liquid provided by the present invention has high polishing efficiency, can reduce polishing costs, and improve product quality. The surface roughness of the material obtained after polishing is low and the number of scratches is small, which effectively improves the polished surface quality and enhances the overall aesthetics and durability of the material. Moreover, the polishing liquid does not contain toxic substances such as chromium / phosphorus, and is environmentally friendly. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] To further illustrate the present invention, the following examples are provided for detailed description. The raw materials used in the following examples and comparative examples are all commercially available products; the raw material companies listed below are one of the sources for purchasing the raw materials.

[0041] In the present invention:

[0042] Silica sol model JN60-40 / 1, particle size 55-65 nm, solid content 40±1%, was purchased from Zhejiang Delixin Micro-Nano Technology Co., Ltd.

[0043] Preparation of corrosion inhibitor

[0044] (1) Deionized water was added to a reaction kettle, and the temperature was raised to 50° C. Copolyvidone powder was slowly added according to a solid-liquid mass ratio of 1:9, and the mixture was stirred at 300 rpm for 40 minutes. After the dissolution was completed, the system was cooled to 30° C. to obtain a copolyvidone solution for use;

[0045] (2) dissolving ammonium persulfate in deionized water at a solid-liquid mass ratio of 1:6 at 30° C., and stirring at 150 rpm until a transparent solution is obtained to obtain an ammonium persulfate solution;

[0046] (3) The ammonium persulfate solution was added dropwise to the copolyvidone solution at a rate of 5 mL / min, and the mixture was stirred at 300 rpm and kept in a water bath at 30±2°C. After the addition was completed, the stirring was continued for 60 min to obtain a corrosion inhibitor, wherein the amount added was converted based on a mass ratio of copolyvidone to ammonium persulfate of 1:0.4.

[0047] Preparation of surfactants

[0048] Accurately weigh the raw materials according to the mass ratio in Table 1 and mix them evenly to obtain a surfactant;

[0049] Table 1 Proportions of surfactant components

[0050] Raw material name Surfactant 1 Surfactant 2 Surfactant 3 Perfluoropolyether 1 1 1 Coconut oil alkanolamide 1 1.5 2 Sodium dodecylbenzenesulfonate 0.6 0.7 0.8 Raw material name Surfactant 4 Surfactant 5 Surfactant 6 Perfluoropolyether 1 1 / Coconut oil alkanolamide / 1.5 1.5 Sodium dodecylbenzenesulfonate 0.7 / 0.7

[0051] Preparation of Examples

[0052] Accurately weigh the raw materials according to the mass fractions in Table 2;

[0053] Step 1. Place silica sol, surfactant, water-retaining agent and water in a mixing container and mix and stir evenly to obtain mixture A;

[0054] Step 2. Mixture A is stirred at a speed of 200-300 r / min, and a dispersant and a corrosion inhibitor are added while stirring. After stirring for 40-50 minutes, the polishing liquid of Examples 1-4 is obtained.

[0055] Table 2 Mass fractions of raw materials in Examples 1-4

[0056]

[0057]

[0058] Note: “ / ” in the table means no additive.

[0059] Preparation of Comparative Example

[0060] In order to verify the influence of each component in the formula on the overall performance, the components were omitted and replaced based on the formula of Example 3, as follows:

[0061] Comparative Example 1: Surfactant 2 was replaced with Surfactant 4, and the rest was the same as in Example 3;

[0062] Comparative Example 2: Surfactant 2 was replaced with Surfactant 5, and the rest was the same as in Example 3;

[0063] Comparative Example 3: Surfactant 2 was replaced with Surfactant 6, and the rest was the same as in Example 3;

[0064] Comparative Example 4: No corrosion inhibitor was added, and the rest was the same as in Example 3;

[0065] Comparative Example 5: The corrosion inhibitor was replaced with ammonium persulfate, and the rest was the same as in Example 3;

[0066] The comparative example preparation method is as follows:

[0067] Accurately weigh the raw materials according to the mass fractions in Table 3;

[0068] Step 1. Place silica sol, surfactant, water-retaining agent and water in a mixing container and mix and stir evenly to obtain mixture A;

[0069] Step 2. Mixture A is stirred at a speed of 200-300 r / min, and a dispersant and a corrosion inhibitor are added while stirring. After stirring for 40-50 minutes, the polishing liquids of Comparative Examples 1-5 are obtained.

[0070] Table 3 Mass fractions of raw materials in Comparative Examples 1-4

[0071]

[0072] Note: “ / ” in the table means no additive.

[0073] Performance Testing

[0074] The performance of the polishing liquids for aluminum alloy materials prepared in Examples 1-4 and Comparative Examples 1-5 was tested. The test method is as follows. The test results are shown in Table 4 below.

[0075] The polishing liquids prepared in Examples 1-4 and Comparative Examples 1-5 were used to polish the aluminum alloy material. The aluminum alloy material used was a 6061 aluminum alloy test piece of uniform specification with a size of 100 mm × 100 mm × 5 mm. The specimen was pre-ground to a surface roughness of 200 nm before polishing. During the polishing process, the pressure was 200 g / cm, the polishing disk speed was 70 r / min, the polishing liquid flow rate was 4 ± 0.2 mL / min, the temperature was 25 ± 2 ° C, and the time was 60 min.

[0076] (1) Polishing rate

[0077] Weigh the mass of the aluminum alloy specimen before polishing, record it as M0, perform polishing according to the above polishing process parameters, thoroughly clean and dry the aluminum alloy material after polishing, weigh its mass after polishing, record it as M1, and calculate the polishing rate according to the following formula:

[0078]

[0079] Where: M0——mass of aluminum alloy material before polishing, mg;

[0080] M1——mass of aluminum alloy material after polishing, mg;

[0081] ρ——density of aluminum alloy, g / cm 3 ;

[0082] A——polishing area, cm 2 ;

[0083] T——polishing time, h.

[0084] (2) Surface roughness

[0085] A total of 5 points were selected, including the periphery and center of the aluminum alloy test piece polished with the polishing liquids of Examples 1-4 and Comparative Examples 1-5. The surface roughness was tested using a surface roughness meter. The roughness of the 5 points was tested separately, and each point was measured 3 times to take the average roughness value.

[0086] (3) Suspension stability

[0087] The polishing liquids of Examples 1-4 and Comparative Examples 1-5 were stored at room temperature in the dark, and the stratification of the polishing liquids was examined, thereby examining their suspension stability.

[0088] (4) Scratching degree

[0089] The number of scratches was observed using a microscope at five times magnification, and five locations, including the periphery and center of the polished aluminum alloy specimen, were selected for observation.

[0090] Table 4 Application performance test of each polishing liquid

[0091]

[0092]

[0093] Result analysis:

[0094] The test results in Table 4 show that the polishing liquids of Examples 1-4 have high polishing efficiency, good fine polishing effect, good dispersibility, and the particles are not easy to agglomerate. They are not easy to precipitate after long-term storage, which effectively extends the service life of the polishing liquid, reduces the waste and replacement frequency of the polishing liquid, and have excellent overall performance, meeting the requirements of fine polishing processing of aluminum alloys.

[0095] Comparative Examples 1-3 lack coconut oil alkanolamide, sodium dodecylbenzenesulfonate, and perfluoropolyether, respectively, resulting in a significant decrease in the dispersion stability of the abrasive in the polishing liquid and poor processing performance, demonstrating that the surfactant provided by the present invention has a synergistic effect of promoting dispersion and improving the polishing effect in the polishing liquid system;

[0096] Comparative Example 4 lacks a corrosion inhibitor, resulting in reduced polishing efficiency and poor polishing effect, demonstrating that the corrosion inhibitor provided by the present invention can weaken the bonding force between atoms on the surface of the material, making the material easier to remove and achieving efficient and uniform polishing;

[0097] The lack of copolyvidone in Comparative Example 5 resulted in higher surface roughness, more scratches, and worse stability of the polishing liquid, which proved that the corrosion inhibitor provided by the present invention effectively slowed down corrosion compared with the traditional method of directly adding oxidants, and also played a role in dispersion and stability.

[0098] In summary, the polishing liquids prepared in Examples 1-4 have high polishing efficiency, can reduce polishing costs, and improve product quality. The surface roughness of the materials obtained after polishing is low and the number of scratches is small, which effectively improves the polished surface quality and enhances the overall aesthetics and durability of the materials. Moreover, the polishing liquid does not contain toxic substances such as chromium / phosphorus, and is environmentally friendly.

[0099] Finally, it should be noted that the above embodiments and comparative examples are only used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polishing composition for fine polishing of aluminum alloy surface, characterized in that: The composition comprises the following components in parts by mass: The dispersant is selected from at least one of polyethylene glycol, sodium polyacrylate, and polyvinyl pyrrolidone; The surfactant is composed of perfluoropolyether, coconut oil alkanolamide and sodium dodecylbenzenesulfonate; The corrosion inhibitor consists of copolyvidone and ammonium persulfate in a mass ratio of 1:(0.3-0.5).

2. The polishing composition according to claim 1, wherein The mass percentage of silicon dioxide in the silica sol is 30-45%.

3. The polishing composition according to claim 2, wherein The silicon dioxide is silicon dioxide particles with a particle size of 50-100 nm.

4. The polishing composition according to claim 1, wherein The surfactant consists of perfluoropolyether, coconut oil alkanolamide and sodium dodecylbenzenesulfonate in a mass ratio of 1: (1-2): (0.6-0.8).

5. The polishing composition according to claim 1, wherein The water-retaining agent is at least one of butanediol, glycerol and hexylene glycol.

6. A polishing liquid for fine polishing of aluminum alloy surface, characterized in that: The polishing liquid contains the polishing composition according to any one of claims 1 to 5.

7. The polishing liquid according to claim 6, characterized in that The polishing liquid also contains water.

8. The polishing liquid according to claim 7, characterized in that The polishing liquid contains the following components in parts by mass:

9. The method for preparing the polishing liquid according to claim 7 or 8, characterized in that: The preparation method comprises the following steps: Step 1. Place silica sol, surfactant, water-retaining agent and water in a mixing container and mix and stir evenly to obtain mixture A; Step 2. Stirring the mixture A at a speed of 200-300 r / min, adding a dispersant and a corrosion inhibitor while stirring, and stirring for 40-50 minutes to obtain the polishing liquid.

10. Use of the polishing composition according to any one of claims 1 to 5 in preparing a polishing preparation for aluminum alloys.

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