Anodic oxidation normal-temperature and high-temperature sealing agent and sealing treatment method

Abstract

The invention relates to the technical field of anodic oxidation treatment, and discloses an anodic oxidation normal-temperature and high-temperature sealing treatment agent, the sealing treatment agent comprises a normal-temperature treatment agent and a high-temperature treatment agent, each liter of normal-temperature sealing liquid is composed of 1-3 g of nickel fluoride, 5-8 g of potassium sodium tartrate tetrahydrate, 10-15 mL of boehmite sol and 0.05-0.2 g of SrTiO3 / BPQDs heterojunction catalyst; each liter of the high-temperature confining liquid is composed of 3-8 g of lanthanum nitrate, 5-15 g of aluminum citrate, 0.1-1 g of PNIPAM, 0.4 g of PNIPAM and 1-3 g of boric acid. According to the invention, a compact composite film layer can be finally obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of anodizing treatment, and in particular to an anodizing normal-temperature and high-temperature sealing agent and a sealing treatment method. Background Art

[0002] Anodizing, the most widely used protective treatment technology in aluminum alloy surface engineering, electrochemically constructs a high-hardness alumina ceramic layer on the substrate surface, significantly improving the material's corrosion resistance (salt spray test increases by 6-8 times), microhardness (up to HV400-600), and wear resistance (friction coefficient reduced to 0.15-0.25). However, its unique porous layered structure (porosity 12-18%, pore size 10-30nm), while endowed with excellent physical adsorption properties, also brings two key drawbacks: the high specific surface area increases the probability of pollutant adsorption; and the diffusion rate of the corrosive medium increases.

[0003] Therefore, a sealing process must be used to achieve physical and chemical modification of the microporous structure. However, the sealing treatment effect of the existing technology is not high. Summary of the Invention

[0004] The main purpose of the present invention is to solve the technical problem of low sealing effect in the prior art. A room-temperature and high-temperature sealing treatment agent for anodizing is provided, wherein the sealing treatment agent comprises a room-temperature treatment agent and a high-temperature treatment agent, wherein each liter of the room-temperature sealing solution comprises 1-3g of nickel fluoride, 5-8g of potassium sodium tartrate, 10-15mL of boehmite sol, and 0.05-0.2g of a SrTiO3 / BPQDs heterojunction catalyst; and each liter of the high-temperature sealing solution comprises 3-8g of lanthanum nitrate, 5-15g of aluminum citrate, 0.1-1g of PNIPAM, and 1-3g of boric acid.

[0005] Each liter of the room temperature sealing liquid is composed of 1-3 g of nickel fluoride, 5-8 g of potassium sodium tartrate, 10-15 mL of boehmite sol, and 0.05-0.2 g of SrTiO3 / BPQDs heterojunction catalyst.

[0006] The preparation method of the SrTiO3 / BPQDs heterojunction catalyst is as follows:

[0007] Disperse 0.5 g of SrTiO3 nanopowder in 50-60 mL of ethanol and ultrasonicate for 20-35 min;

[0008] Add 10-15 mg of BPQDs and stir magnetically under nitrogen for 12 h;

[0009] The product was collected by centrifugation and dried in vacuum at 60°C to obtain the SrTiO3 / BPQDs heterojunction catalyst.

[0010] The BPQDs are 3-5 nm in size and have a 2-3 layer structure.

[0011] Each elevated temperature blocking solution is composed of 3-8 g of lanthanum nitrate, 5-15 g of aluminum citrate, 0.1-1 g of PNIPAM 0.4 g, and 1-3 g of boric acid.

[0012] The PNIPAM is modified with a terminal carboxyl group and has a MW of 2000-4000.

[0013] The present invention also provides a closed treatment method, comprising the following steps:

[0014] After degreasing and pickling the aluminum workpiece, anodizing is performed to obtain the workpiece to be sealed;

[0015] Using a room temperature sealing liquid, the workpiece to be sealed is subjected to a room temperature sealing treatment at 20-35 degrees Celsius to obtain a room temperature sealed workpiece;

[0016] Use high temperature sealing liquid to perform high temperature sealing treatment on normal temperature sealed workpieces at 85-98 degrees Celsius;

[0017] After washing with water and drying, a sealed workpiece is obtained.

[0018] The present invention has the following beneficial effects:

[0019] At room temperature, the SrTiO3 / BPQDs heterojunction of the present invention produces e under visible light. - -h + Yes, promote Ni 2+ →Ni(OH)2 deposition; boehmite sol fills 30-50nm pores to improve pre-sealing efficiency;

[0020] At high temperature, the PNIPAM of the present invention shrinks to form a 3D network template, guiding the preferential growth of LaAlO3 nanocrystals; aluminum citrate is pyrolyzed to form AlO6 octahedrons and La 3+ A coherent interface is formed, and finally a dense composite film layer is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Graph showing experimental results of an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The terms "first," "second," "third," "fourth," and so on (if any) in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. A room-temperature and high-temperature sealing treatment agent for anodizing, the sealing treatment agent comprising a room-temperature treatment agent and a high-temperature treatment agent, wherein each liter of the room-temperature sealing solution comprises 1-3 g of nickel fluoride, 5-8 g of potassium sodium tartrate, 10-15 mL of boehmite sol, and 0.05-0.2 g of a SrTiO3 / BPQDs heterojunction catalyst; and each liter of the high-temperature sealing solution comprises 3-8 g of lanthanum nitrate, 5-15 g of aluminum citrate, 0.1-1 g of PNIPAM, and 1-3 g of boric acid.

[0023] As a preferred embodiment, each liter of room temperature sealing liquid is composed of 1-3 g of nickel fluoride, 5-8 g of potassium sodium tartrate, 10-15 mL of boehmite sol, and 0.05-0.2 g of SrTiO3 / BPQDs heterojunction catalyst.

[0024] As a preferred embodiment, the preparation method of SrTiO3 / BPQDs heterojunction catalyst is as follows:

[0025] Disperse 0.5 g of SrTiO3 nanopowder in 50-60 mL of ethanol and ultrasonicate for 20-35 min;

[0026] Add 10-15 mg of BPQDs and stir magnetically under nitrogen for 12 h;

[0027] The product was collected by centrifugation and dried in vacuum at 60°C to obtain the SrTiO3 / BPQDs heterojunction catalyst.

[0028] As a preferred embodiment, BPQDs are 3-5 nm in diameter and have a 2-3 layer structure.

[0029] As a preferred embodiment, each elevated temperature blocking solution is composed of 3-8 g of lanthanum nitrate, 5-15 g of aluminum citrate, 0.1-1 g of PNIPAM, and 1-3 g of boric acid.

[0030] As a preferred embodiment, PNIPAM is modified with a terminal carboxyl group and has a MW of 2000-4000.

[0031] For ease of understanding, the specific process of the embodiment of the present invention is described below. Example 1 of the anodic oxidation room temperature and high temperature sealing treatment method in the embodiment of the present invention includes:

[0032] Room temperature treatment agent and high temperature treatment agent, each liter of room temperature sealing liquid consists of 2g nickel fluoride, 7g potassium sodium tartrate, 12mL boehmite sol and 0.1g SrTiO3 / BPQDs heterojunction catalyst;

[0033] The high-temperature blocking solution is composed of 5 g of lanthanum nitrate, 8 g of aluminum citrate, 0.5 g of PNIPAM and 2 g of boric acid.

[0034] 1. Substrate pretreatment

[0035] Select 6061 aluminum alloy test piece (50×50×2mm)

[0036] Degreasing: Soak in 60℃ alkaline detergent for 10 minutes (pH=10.5)

[0037] Alkali etching: 50g / L NaOH solution, 60℃ for 90s

[0038] Anodic oxidation: 15% H2SO4 solution, constant temperature of 18°C, DC 15V oxidation for 30 minutes (film thickness 20±2μm)

[0039] 2. Catalyst Preparation

[0040] 0.5 g SrTiO3 nanopowder was dispersed in 50 mL ethanol and ultrasonicated for 30 min.

[0041] Add 10 mg of BPQDs (Xi'an Qiyue Biotechnology Co., Ltd., length: 2.95 nm, thickness: 3.59 nm) and stir magnetically under nitrogen protection for 12 h (300 rpm, 25 ° C)

[0042] The solution was collected by centrifugation (8000 rpm, 10 min) and dried under vacuum at 60°C for later use.

[0043] Preparation method of BPQDs (Xi'an Qiyue):

[0044] (1) Under anaerobic conditions, dispersing black phosphorus with a particle size of 5 to 50 μm in an organic solvent to obtain a dispersion liquid, wherein the concentration of black phosphorus in the dispersion liquid is 0.6 to 1.2 mg / mL;

[0045] (2) diluting the first dispersion by 5 to 10 times with an organic solvent, and then adding sodium hydroxide to obtain a dispersion, wherein the mass ratio of black phosphorus to sodium hydroxide in the second dispersion is 0.006 to 0.012:1;

[0046] (3) The two dispersions are placed in a sealed container and heated at a temperature of 120-160°C for 6-18 hours. After the reaction is completed, the resulting reaction solution is cooled to room temperature, centrifuged, and the supernatant is collected to obtain black phosphorus quantum dots.

[0047] The concentration of black phosphorus in the binary dispersion is 0.06-0.12 mg / mL.

[0048] In step (2), sodium hydroxide is added to the two dispersions. On the one hand, the sodium ions and hydroxide ions in the sodium hydroxide can be intercalated into the black phosphorus sheets, weakening the van der Waals forces between the black phosphorus sheets, thereby improving the stripping efficiency. On the other hand, the excess hydroxide ions can be adsorbed on the black phosphorus surface to protect the black phosphorus, thereby improving the stability of the black phosphorus. Therefore, the mass ratio of the black phosphorus in the two dispersions to the sodium hydroxide is 0.006 to 0.012:1.

[0049] In addition, if the concentration of sodium hydroxide is too low, the probability of its intercalation into the black phosphorus layer will be reduced, so an excess of sodium hydroxide is generally added. However, if too much NaOH is added, the solubility of sodium hydroxide in the two-dispersion solution is not very high, and adding too much will waste material.

[0050] In step (2), 2 to 4 mL of the first dispersion is taken, 18 to 36 mL of an organic solvent is added, and then 200 to 400 mg of sodium hydroxide is added to obtain a second dispersion.

[0051] Closed treatment experimental process

[0052] 1. Normal temperature closed stage

[0053] Solution preparation:

[0054] Each liter of room temperature sealing solution consists of 2 g of nickel fluoride, 7 g of potassium sodium tartrate, 12 mL of boehmite sol and 0.1 g of SrTiO3 / BPQDs heterojunction catalyst.

[0055] Operation process:

[0056] Dissolve nickel fluoride and potassium sodium tartrate in 600 mL of deionized water;

[0057] Boehmite sol was slowly added under magnetic stirring (rate 2 mL / min);

[0058] Add the catalyst suspension and adjust the volume to 1 L (pH = 5.2-5.6);

[0059] The test piece was immersed in the solution and a 500W LED white light source (illuminance 3000 lux) was turned on;

[0060] Treat at 25℃ for 18min, take out and rinse with deionized water

[0061] 2. High temperature sealing stage

[0062] Solution preparation:

[0063] Each high-temperature blocking solution is composed of 5g of lanthanum nitrate, 8g of aluminum citrate, 1.2g of PNIPAM (Shaanxi Xingbei Aike Biological MW: 4000) and 2g of boric acid.

[0064] Process control:

[0065] Use a programmable temperature bath (±0.5°C accuracy);

[0066] The pH of the solution was maintained at 4.8-5.2 (adjusted by adding dilute nitric acid);

[0067] Compressed air (0.2MPa) is continuously introduced during the treatment process to prevent components from stratifying;

[0068] The sealing temperature is 95 degrees Celsius, and after completion, it is taken out and rinsed with deionized water;

[0069] Closure effect evaluation

[0070] The neutral salt spray test method was used to test for 720 hours in accordance with GB / T10125-2012. Corrosion resistance was assessed according to QB / T3832-99, "Corrosion Test Results of Metal Coatings on Light Industrial Products" (10 levels, with 10 being no corrosion). Ten workpieces were evaluated simultaneously and the average value was calculated.

[0071] Example 2

[0072] Room temperature treatment agent and high temperature treatment agent, each liter of room temperature sealing liquid consists of 3g nickel fluoride, 8g potassium sodium tartrate, 11mL boehmite sol and 0.09g SrTiO3 / BPQDs heterojunction catalyst;

[0073] Each elevated temperature blocking solution is composed of 4 g of lanthanum nitrate, 9 g of aluminum citrate, 1.6 g of PNIPAM (Shaanxi Xingbei Aike Biological MW: 2000) and 3 g of boric acid.

[0074] Comparative Example 1

[0075] Same as Example 1, but without adding SrTiO3 / BPQDs heterojunction catalyst.

[0076] Comparative Example 2

[0077] Same as Example 1, but using polyvinyl alcohol (MW: 4000) instead of PNIPAM.

[0078] Comparative Example 3

[0079] Same as Example 1, except that the boehmite sol was replaced by silica sol.

[0080] Comparative Example 4

[0081] Same as Example 1, but lanthanum nitrate was replaced by potassium nitrate.

[0082] The experimental results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] Data comparison of SrTiO3 / BPQDs heterojunction, see Table 2:

[0087] Table 2

[0088]

[0089] The photocurrent density of the heterojunction in this example was increased to 6.5 times that of pure SrTiO3, attributed to the broad spectral response of BPQDs (visible to near-infrared) and efficient charge separation at the heterojunction interface. The impedance dropped to 21% of that of the pure phase, indicating a significant increase in the carrier mobility of the composite material. Higher hydroxyl radical (·OH) signal intensity was detected by EPR (electron paramagnetic resonance) (3.2 times that of the pure phase in the heterojunction), confirming the enhanced photocatalytic oxidation capability.

[0090] The experimental results of Example 1 are shown in Figure 1 , the data comparison of Example 1 and competitors is shown in Table 2:

[0091] Table 2

[0092]

[0093] It can be seen that the present invention has an excellent sealing effect.

[0094] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A normal temperature and high temperature sealing treatment agent for anodizing, characterized in that: The sealing treatment agent includes a room temperature treatment agent and a high temperature treatment agent. Each liter of the room temperature sealing liquid is composed of 1-3g of nickel fluoride, 5-8g of potassium sodium tartrate, 10-15mL of boehmite sol and 0.05-0.2g of SrTiO3 / BPQDs heterojunction catalyst; each liter of the high temperature sealing liquid is composed of 3-8g of lanthanum nitrate, 5-15g of aluminum citrate, 0.1-1g of PNIPAM and 1-3g of boric acid.

2. The anodic oxidation room temperature and high temperature sealing treatment agent according to claim 1, characterized in that: Each liter of the room temperature sealing liquid is composed of 1-3 g of nickel fluoride, 5-8 g of potassium sodium tartrate, 10-15 mL of boehmite sol, and 0.05-0.2 g of SrTiO3 / BPQDs heterojunction catalyst.

3. The anodic oxidation room temperature and high temperature sealing treatment agent according to claim 2, characterized in that: The preparation method of the SrTiO3 / BPQDs heterojunction catalyst is as follows: Disperse 0.5 g of SrTiO3 nanopowder in 50-60 mL of ethanol and ultrasonicate for 20-35 min; Add 10-15 mg of BPQDs and stir magnetically under nitrogen for 12 h; The product was collected by centrifugation and dried in vacuum at 60°C to obtain the SrTiO3 / BPQDs heterojunction catalyst.

4. The anodic oxidation room temperature and high temperature sealing treatment agent according to claim 3, characterized in that: The BPQDs are 3-5 nm in size and have a 2-3 layer structure.

5. The anodic oxidation room temperature and high temperature sealing treatment agent according to claim 1, characterized in that: Each elevated temperature blocking solution is composed of 3-8 g of lanthanum nitrate, 5-15 g of aluminum citrate, 0.1-1 g of PNIPAM 0.4 g, and 1-3 g of boric acid.

6. The anodic oxidation room temperature and high temperature sealing treatment agent according to claim 5, characterized in that: The PNIPAM is modified with a terminal carboxyl group and has a MW of 2000-4000.

7. The sealing treatment method of anodizing room temperature and high temperature sealing agent according to claim 1, characterized in that: The following steps are involved: After degreasing and pickling the aluminum workpiece, anodizing is performed to obtain the workpiece to be sealed; Using a room temperature sealing liquid, the workpiece to be sealed is subjected to a room temperature sealing treatment at 20-35 degrees Celsius to obtain a room temperature sealed workpiece; Use high temperature sealing liquid to perform high temperature sealing treatment on normal temperature sealed workpieces at 85-98 degrees Celsius; After washing with water and drying, a sealed workpiece is obtained.

8. The method for anodizing and sealing at room temperature and high temperature according to claim 1, characterized in that: During the normal temperature sealing process, an LED light source is used to illuminate the workpiece to be sealed.

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