Anti-stripping, anti-scraping and anti-corrosion coating and preparation method thereof

Abstract

The invention belongs to the field of material science and engineering, and particularly relates to an anti-stripping, anti-scraping and corrosion-resistant coating and a preparation method thereof. A preparation method of an anti-stripping, anti-scraping and corrosion-resistant coating is characterized by comprising the following steps that an aluminum plate is pretreated, then subsonic spraying is adopted, aluminum-coated nickel alloy powder is sprayed on the surface of aluminum alloy to prepare a base, then Ti3AlC2 ceramic powder is sprayed, and the anti-stripping, anti-scraping and corrosion-resistant coating is obtained. The corrosion-resistant coating provided by the invention has excellent scratch damage resistance, salt spray corrosion can be effectively prevented, and the service life of the 7-series aluminum alloy is prolonged; and further, a more comprehensive anti-corrosion effect is provided for the material.

Description

Technical Field

[0001] The invention belongs to the field of material science and engineering, and specifically relates to an anti-peeling, anti-scratch corrosion-resistant coating and a preparation method thereof. Background Art

[0002] In modern industrial applications, surface coating technology is widely used to improve the wear resistance, corrosion resistance and thermal stability of materials. Especially in the fields of aerospace, automobile manufacturing and electronic equipment, the requirements for material surface properties are increasing. Among many coating materials, Ti3AlC2 ceramics have attracted widespread attention due to its excellent high temperature performance, oxidation resistance and wear resistance.

[0003] However, when spraying Ti3AlC2 powder, directly coating it on a metal substrate often results in poor bonding between the coating and the substrate. This poor bonding causes the coating to easily peel off from the substrate during use, thereby reducing the service life and overall performance of the coating; therefore, there is an urgent need for an anti-peeling, anti-scratch, and corrosion-resistant coating and a preparation method thereof. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a method for preparing an anti-peeling and anti-scratch corrosion-resistant coating, comprising the following steps:

[0005] The aluminum plate is pretreated, and then aluminum-clad nickel alloy powder is sprayed on the aluminum alloy surface by subsonic spraying to prepare a primer, and then Ti3AlC2 ceramic powder is sprayed to obtain an anti-peeling, anti-scratch and corrosion-resistant coating.

[0006] Furthermore, the spraying process uses 400 mesh fine powder.

[0007] Furthermore, the aluminum alloy is a 7 series aluminum alloy.

[0008] Furthermore, the pretreatment is sandblasting.

[0009] A corrosion resistant coating that resists peeling, scratching and scratching.

[0010] Beneficial Effects

[0011] (1) According to the present invention, a peeling-resistant, scratch-resistant and corrosion-resistant coating and its preparation method are provided. Based on the long-term corrosion results, it is judged that the coatings sprayed with coarse powder and fine powder titanium aluminum carbon can effectively prevent salt spray corrosion and improve the service life of 7 series aluminum alloys. In addition, compared with the 7 series aluminum alloys simply sprayed with paint and not sprayed with any coating, the 7 series aluminum alloys sprayed with titanium aluminum carbon coating can provide a more comprehensive anti-corrosion effect for the material; and the 7 series aluminum alloys sprayed with titanium aluminum carbon coating have excellent scratch damage resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0013] Figure 1 The corrosion morphology of the unprotected area after the fine powder and coarse powder of the 7 series aluminum alloy sheet of the present invention are sprayed;

[0014] Figure 2 The morphology of the protective ceramic layer after corrosion after spraying the fine powder and coarse powder of the 7 series aluminum alloy sheet of the present invention;

[0015] Figure 3 The morphology of the protective ceramic layer of the 7 series aluminum alloy sheet after fine powder and coarse powder spraying of the present invention and after scratching and corrosion;

[0016] Figure 4 This is a corrosion test result diagram of the 7 series aluminum alloy of the present invention in salt spray;

[0017] Figure 5 This is a comparison diagram of the corrosion of the aluminum alloy part sprayed with paint only and the aluminum alloy part sprayed with coarse powder after 500 hours;

[0018] Figure 6 This is a corrosion diagram of an aluminum alloy part of the present invention that is only sprayed with paint after 500 hours;

[0019] Figure 7 This is the corrosion diagram of the aluminum alloy part sprayed with fine powder after 500 hours;

[0020] Figure 8 , Fig. 9 This is the corrosion diagram of the aluminum alloy part sprayed with coarse powder after 500 hours;

[0021] Fig.10 The corrosion test results (1000h) of the uncoated 7 series aluminum alloy of the present invention in salt spray;

[0022] Fig.11 The corrosion test results (1000h) of the 7 series aluminum alloy sprayed with paint in salt spray of the present invention;

[0023] Fig.12 The corrosion test results (1000h) of the 7 series aluminum alloy sprayed with fine Ti3AlC2 powder in salt spray of the present invention;

[0024] Fig.13The corrosion test results (1000h) of the 7 series aluminum alloy sprayed with coarse Ti3AlC2 powder in salt spray of the present invention;

[0025] Fig.14 is a corrosion surface diagram of the 7 series aluminum alloy of the present invention;

[0026] Fig.15 This is a pitting diagram of the 7 series aluminum alloy sprayed with paint only according to the present invention;

[0027] Fig.16 The corrosion morphology of the paint-sprayed surface and the unpainted back surface of the 7 series aluminum alloy of the present invention (1500h);

[0028] Fig.17 The corrosion morphology of the 7 series aluminum alloy surface of the present invention after spraying coarse titanium aluminum carbon powder, and then spraying a layer of paint sealing layer, and the back side without spraying (1500h);

[0029] Fig.18 The surface of the 7 series aluminum alloy of the present invention is sprayed with fine titanium aluminum carbon powder, and then a layer of paint is sprayed to seal the holes, and the corrosion morphology of the back side is not sprayed (1500h);

[0030] Fig.19 , Fig. 20 The corrosion morphology of the untreated 7 series aluminum alloy surface and back surface of the present invention (1500h);

[0031] Fig.21 This is a grid scratch test diagram of the 7 series aluminum alloy surface sprayed with paint in an atmospheric environment of the present invention;

[0032] Fig. 22 This is a grid scratch test diagram of the 7 series aluminum alloy surface sprayed with coarse titanium aluminum carbon powder + paint sealing;

[0033] Fig.23 This is a grid scratching test diagram of the 7 series aluminum alloy surface sprayed with fine titanium aluminum carbon powder + paint sealing. DETAILED DESCRIPTION

[0034] The following will be combined with Example 1 of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiment is only a 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 making creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] First, a layer of aluminum-clad nickel alloy powder is sprayed on the surface of the 7 series aluminum alloy by subsonic spraying, and then Ti3AlC2 powder is sprayed to obtain an anti-peeling, anti-scratch and corrosion-resistant coating.

[0037] In the experiment, 400 mesh fine powder and 200-400 mesh range powder were used for spraying. It was found that 400 mesh fine powder is not prone to sputtering, while 200-400 mesh range powder is prone to sputtering. The reason is that large particles are more likely to bounce when colliding with the surface of the aluminum plate under the impact of high-speed airflow; according to the spraying results, 400 mesh fine powder is more easily oxidized, and the sprayed surface is grayish white, while the surface of the sample after spraying with 200-400 mesh range powder is mainly grayish black; This shows that the powder is too fine and is easily oxidized by combining with oxygen.

[0038] In the experiment, a total of 30 7 series aluminum alloy samples were prepared, and anti-corrosion coatings were sprayed on the surface to meet the test characterization requirements of the system. This test selected two types: one without an aluminum-clad nickel intermediate layer and the other with an aluminum-clad nickel intermediate layer; and 400 mesh powder and 200-400 mesh powder were sprayed respectively for a systematic comparative test. The 7 series aluminum alloy spraying requires the use of aluminum-clad nickel alloy powder as a base. Both fine powder and coarse powder can be evenly attached to the sample surface, and both can achieve uniform spraying.

[0039] First, a short-term corrosion test was conducted. At a constant temperature of 35°C, the corrosion was carried out in a salt spray test chamber for 216 hours (9 days). Then, the samples tested included 7 series aluminum alloy sheets with nickel-aluminum primer, titanium-aluminum-carbon ceramic layer, and paint-filled pore layer sprayed on the surface in sequence; the back of the sample was not sprayed with paint for comparison test; the sample surface sprayed with paint and the surface sprayed with composite layer were scratched for comparison test; the national standard adopted was GB / T 10125-1997, combined with Figure 1 The corrosion morphology of the unprotected area can be obtained: a little pitting occurs; the left picture is coarse powder spraying, and the right picture is fine powder spraying; Figure 2 The morphology of the protective ceramic layer after corrosion can be obtained: the surface has not changed; the left picture is coarse powder spraying, and the right picture is fine powder spraying; Figure 3 It can be seen from the figure that the protective ceramic layer is scratched and corroded: pitting occurs inside the coarse powder sprayed sample, while there is no change inside the fine powder sprayed sample; the left picture is coarse powder sprayed, and the right picture is fine powder sprayed. Through the short-time corrosion test, it can be seen that in the short-time corrosion, under the condition of no damage, the corrosion resistance of fine powder and coarse powder spraying is similar; when there is damage, the sample sprayed with fine powder is more corrosion-resistant than the sample sprayed with coarse powder.

[0040] Secondly, a long-term corrosion test was carried out, in which the corrosion was carried out in a salt spray test chamber for 500 hours. Figure 4It can be seen that the upper two pieces are coated with fine powder. It can be seen that there is basically no corrosion on the surface, and only a few bubbles exist. The internal structure of the bubbles will be verified later; while the aluminum alloy parts without any coating (the two pieces below) have been severely corroded on the surface, and the surface is completely covered with corrosion pits;

[0041] Figure 5 It can be seen that by comparing the aluminum alloy parts that are only sprayed with paint and the aluminum alloy parts that are sprayed with coarse powder, it can be seen that the coating that is only sprayed with paint is very smooth, without corrosion, and has a certain anti-corrosion effect, but is not resistant to impact and scratches, which will be explained below; while the aluminum alloy parts sprayed with coarse powder have only a small amount of bubbles on the surface, no obvious corrosion, and are resistant to impact and scratches (circled). Figure 6 For aluminum alloy parts that were only sprayed with paint, after 500 hours of corrosion, scratching and hammering tests were carried out. It was found that the paint layer was very easy to peel off when a knife scratched the paint layer, and large pieces of paint peeled off at the hammering point when a hammer was used for the hammering test.

[0042] Figure 7 For aluminum alloy parts sprayed with fine powder, only a small amount of paint will fall off when the surface is hit with a hammer, and only a small amount of paint will fall off when scratched with a knife. The sprayed titanium aluminum carbon layer can effectively absorb energy and protect the aluminum alloy substrate from external impact damage. Figure 8 and Fig. 9 For aluminum alloy parts sprayed with coarse powder, only a small amount of paint layer fell off the surface after being hammered with a hammer, and the internal titanium aluminum carbon coating played the role of absorbing energy and protecting the alloy; when the bubbling position was hit with a hammer, it was found that there was only one bubbling layer, and the lower layer was still the paint layer and titanium aluminum carbon layer, which effectively protected the aluminum alloy substrate. These bubbles are probably generated when corrosion occurs. Due to the action of micro batteries, hydrogen and other gases are generated, and the greater pressure generated in the area where the aluminum alloy substrate contacts the corrosive liquid locally pushes up the paint layer to form a bubbling layer.

[0043] Then the corrosion test of 7 series aluminum alloy in salt spray (1000 hours) was carried out. Fig.10 It can be seen that the sample is an uncoated 7 series aluminum alloy. The surface of the alloy has been completely covered with corrosion products, and the matrix can no longer be clearly distinguished. Fig.11 This is the corrosion test result of 7 series aluminum alloy sprayed with paint. The sample has a little bubbling at the edge, and no obvious corrosion points exist in the center area. This shows that spraying paint alone has an anti-corrosion effect. Fig.12 The corrosion test results of 7 series aluminum alloy sprayed with fine Ti3AlC2 powder show that there are bubbles at the edge and no pitting in the center area, indicating that the sample sprayed with fine powder has an anti-corrosion effect.

[0044] Fig.13The corrosion test results of 7 series aluminum alloy sprayed with coarse Ti3AlC2 powder show that there are bubbles on the edge of the sample, but no pitting in the center, indicating that the sample sprayed with coarse powder has an anti-corrosion effect. Fig.14 It can be seen that there is damage on the surface, but the damage effect cannot be distinguished because the undamaged area has been completely covered by pitting. This shows that the unprotected 7 series aluminum alloy has failed in the corrosive environment. Fig.15 It can be seen that obvious pitting has appeared in the scratches and hammer damage.

[0045] Furthermore, the corrosion test of 7 series aluminum alloy in salt spray (1500 hours) was carried out, combined with Fig.16 It can be seen that the corrosion morphology of the 7 series aluminum alloy sprayed paint surface and the unsprayed paint back side, here scratches and hammer defects are artificially created on the sprayed paint surface; it can be seen that the damaged part of the sprayed paint surface has been corroded, while there is no obvious corrosion on the undamaged part, but the corrosion on the unsprayed paint back side is very serious, the substrate can no longer be identified, and the surface is covered with corrosion pits.

[0046] Combination Fig.17 It can be seen that there are artificial scratches and hammer points on the sprayed surface; after corrosion, it was found that there was a little corrosion in the damaged area of ​​the sprayed surface, and there were bubbles, which should be caused by the gas generated during the corrosion process; and, there were only a few corrosion pits on the unsprayed back surface, and the base was clearly visible; the results showed a good anti-corrosion effect.

[0047] Combination Fig.18 It can be seen that Fig.18 Fine titanium-aluminum-carbon powder was sprayed on the surface of the 7 series aluminum alloy, and then a layer of paint was sprayed to seal the holes, and scratches and hammer damage were artificially created on the sprayed surface; after the corrosion test, bubbles appeared on the damaged part of the sprayed surface, which should be caused by the gas generated during the corrosion process, while there was no corrosion on the undamaged part; and, on the unsprayed back side, the aluminum alloy substrate was clearly visible, with only a very small number of pitting pits; therefore, the results showed a very good anti-corrosion effect. Fig.19 and Fig. 20 The untreated 7 series aluminum alloy surface was also artificially scratched and hammered. After corrosion, the surface and back were covered with pitting pits, the base was no longer discernible, and severe corrosion occurred.

[0048] Finally, the scratch test was carried out. The experimental conditions were grid scratching test in atmospheric environment. The material was 7 series aluminum alloy, and the coating was pure paint sprayed on the surface; coarse titanium aluminum carbon ceramic particles were sprayed; fine titanium aluminum carbon ceramic particles were sprayed. The national standard adopted was GB / T 9286-2021; combined Fig.21The test found that the paint layer peeled off significantly during the scratching process, and peeling caused by shear stress occurred at the edge of the scratch; the conclusion is that the scratch resistance of the coating is very poor. Fig. 22 It can be seen that the grid scratch test found that the scratches were very uniform, and there was no coating peeling caused by shearing at the scratches; it showed excellent scratch resistance. Fig.23 The surface of 7 series aluminum alloy was sprayed with fine titanium aluminum carbon powder + paint to seal the holes, and a grid scratch test was performed; the test found that the scratches were uniform, the line thickness was consistent, and there was no coating peeling caused by shearing; the conclusion was that the coating had excellent scratch resistance. Figures 21 to 23 It can be seen that the coating sprayed with titanium aluminum carbon powder and paint sealing layer has good scratch resistance, can prevent shear stress-induced coating peeling during scratching, and exhibits excellent damage resistance.

[0049] In the present invention, regarding thermal spraying, the types of thermal spraying include supersonic flame spraying and plasma spraying. The Ti3AlC2 powder used in the present invention has high reactivity and is not suitable for these spraying methods. Therefore, the preparation method of the present invention adopts low-temperature subsonic spraying, which prevents more Ti3AlC2 from decomposing on the one hand, and is easy to operate on the other hand. Large-area spraying can be achieved by single-handed operation. Therefore, the cost of spraying is very low, and it is very convenient to spray in various field environments, and it has very good workability. This is a very good process innovation.

[0050] The reason why the present invention uses aluminum-coated nickel is that the aluminum plate is prone to generate surface oxides at high temperatures, which reduces the bonding performance between the coating and the aluminum plate. The spraying of aluminum-coated nickel powder protects the aluminum plate and prevents the surface of the aluminum plate from being oxidized. In addition, the Ti3AlC2 used in the present invention also contains aluminum elements, which can easily form a good chemical bond with the aluminum-coated nickel powder, thereby improving the bonding strength of the coating. This is an advantage that other ceramic coatings that do not contain aluminum do not have, and this is a very good innovation point in terms of chemical affinity.

[0051] The present invention needs to perform surface strengthening treatment before spraying, that is, the surface of the aluminum plate is treated by sandblasting. The purpose of this treatment is to strengthen the surface by micro-plastic deformation and to create a relatively rough surface on the surface, which is conducive to the adhesion of the coating on the surface. This treatment method is very important. Conventional spraying does not require this step, so the present treatment method is very innovative.

[0052] The reason why the performance of the spray coating is good is because of the different spray materials used. The Ti3AlC2 coating used in the present invention has very good performance. It has a high elastic modulus and high chemical inertness, especially its excellent marine environment corrosion resistance effect is very unique. All aluminum alloy parts can achieve a comprehensive protection effect as long as one side is sprayed, which is a performance that pure organic coatings do not have; in addition, the sprayed Ti3AlC2 material has low shear strength and excellent damage tolerance, which greatly improves the scratch resistance of the prepared coating, and is better than the scratch resistance of pure paint coatings. This has never been seen in any previous coatings.

[0053] Therefore, the present invention provides an anti-peeling, anti-scratch corrosion-resistant coating and a preparation method thereof, which, by adopting an innovative preparation method, has good anti-scratch and anti-peeling properties, and can also increase the service life of 7 series aluminum alloys, prevent salt spray corrosion, and thereby enhance the protective effect.

Claims

1. A method for preparing an anti-peeling and anti-scratch corrosion-resistant coating, characterized in that: The following steps are involved: The aluminum plate is pretreated, and then aluminum-clad nickel alloy powder is sprayed on the aluminum alloy surface by subsonic spraying to prepare a primer, and then Ti3AlC2 ceramic powder is sprayed to obtain an anti-peeling, anti-scratch and corrosion-resistant coating.

2. The method for preparing a peel-resistant, scratch-resistant, and corrosion-resistant coating according to claim 1, characterized in that: The spraying process uses 400 mesh fine powder.

3. The method for preparing a peel-resistant, scratch-resistant and corrosion-resistant coating according to claim 1, characterized in that: The aluminum alloy is a 7 series aluminum alloy.

4. The method for preparing a peel-resistant, scratch-resistant and corrosion-resistant coating according to claim 1, characterized in that: The pretreatment is sandblasting.

5. An anti-peeling, anti-scratch and corrosion-resistant coating obtained according to the preparation method according to any one of claims 1 to 4.

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