Thermal spraying coating hole sealing structure and manufacturing method

Abstract

The invention relates to the technical field of coating protection, discloses a thermal spraying coating hole sealing structure and a manufacturing method, and aims to prolong the service life of a coating. The structure comprises a coating body formed through a thermal spraying process and a first hole sealing layer used for sealing coating gaps. The coating body is divided into a first coating fixedly connected with the base material and a second coating deposited on the first coating, the first hole sealing layer is arranged between the first coating and the second coating, a gap of the first coating is sealed, the second coating is used for protection, and the situation that the integrity of the hole sealing layer is affected by external abrasion is avoided. According to the scheme, the hole sealing layer is arranged in the middle position, so that the damage of the hole sealing layer caused by external abrasion is effectively prevented, the permeation risk of a corrosive medium is reduced, and the chemical or electrochemical erosion resistance of the coating is remarkably improved, thereby effectively prolonging the service life of the coating. The design is particularly suitable for application scenes requiring high wear resistance and durability, and ensures that the coating keeps stable performance in long-term use.

Description

Technical Field

[0001] The invention relates to the technical field of coating protection, and in particular to a thermal spray coating sealing structure and a manufacturing method thereof. Background Art

[0002] Thermal spray coating is a kind of lamellar functional coating formed by heating the thermal spray powder particles to a molten or semi-molten state, and then depositing them on the substrate surface through beam acceleration and impact, followed by spreading, cooling and stacking. The characteristics of thermal spraying process determine that there are more or less pores inside the coating. The corrosive medium reaches the surface of the protected substrate through the pores, causing chemical or electrochemical corrosion between the coating and the substrate, resulting in cracking, shedding and ultimate failure of the coating.

[0003] In order to reduce the porosity of the coating, the commonly used method is to use a sealant for treatment. According to the different components of the sealant, it can be divided into two categories: organic and inorganic: such as CN105001781B discloses a coating sealing material with silicone resin as a sealant. This type of sealant usually has good adhesion and certain flexibility. Inorganic sealers include amorphous SiO2, phosphates and other substances. For example, CN107880606B introduces a sinking radiation surface coating sealer containing a crystalline chromium tincture solution, hexagonal boron nitride filler and a mixed solution of aluminum dihydrogen phosphate; and CN109423596A proposes a high temperature resistant sealer based on an amorphous SiO2 binder, a nano-oxide particle filler and a boron nitride suspension base material.

[0004] Although these methods help reduce porosity, over long-term use, the coating surface may experience wear, resulting in loss of sealant, which in turn re-exposes pores to corrosive media and causes coating failure. Summary of the invention

[0005] The present invention aims to provide a method for manufacturing a thermal spray coating sealing structure to extend the service life of the coating.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a thermal spray coating sealing structure and a manufacturing method, comprising a coating body formed by a thermal spraying process and a first sealing layer for sealing the gaps in the coating body, the coating body comprising a first coating and a second coating, the first coating is fixedly connected to the substrate, the first sealing layer is fixedly arranged between the first coating and the second coating and the second coating is fixed on the first coating.

[0007] The beneficial effects of this solution are as follows: Generally speaking, the sealing layer formed by the sealing agent is located on the surface of the coating. The reason why the technicians in this field do not set the sealing layer formed by the sealing agent in the middle of the coating or between the substrate and the coating is that the presence of the sealing layer will affect the adhesion strength of the coating, causing the entire coating to fall off during use. This application divides the coating body into a first coating and a second coating, and uses a sealing agent to block the gaps on the surface of the first coating to form a first sealing layer. Subsequently, the second coating is deposited on the first coating after the first sealing layer is formed, and the first sealing layer is protected by the second coating to avoid affecting the sealing layer when the coating is worn, thereby causing the sealing layer to be damaged, and then causing the corrosive medium to reach the protected substrate surface through the pores, causing the coating and the substrate to undergo chemical or electrochemical corrosion, resulting in cracking, falling off, and ultimately the coating failing. Through the above design, when the second coating is subjected to external factors such as mechanical wear, it will not directly affect the internal first sealing layer, thereby reducing the risk of corrosive medium penetration due to damage to the sealing layer. Therefore, this new sealing structure can significantly improve the coating's ability to resist chemical or electrochemical corrosion, thereby effectively extending the coating's service life.

[0008] Furthermore, it also includes a second sealing layer, which is fixedly arranged on a side of the second coating layer away from the first sealing layer and seals the gaps in the second coating layer.

[0009] Beneficial effect: The setting of the first sealing layer and the second sealing layer forms a double closure of the internal pores of the coating, greatly reducing the possibility of corrosive media penetrating into the substrate; at the same time, even if the external environment causes wear or damage to the coating surface, the second sealing layer can continue to provide an effective barrier to prevent corrosive media from entering.

[0010] In addition, due to the additional protective layer (i.e., the second sealing layer), the durability and stability of the entire coating system are significantly improved, which not only reduces the risk of coating failure, but also means reduced maintenance requirements, thereby effectively extending the actual service life of the coating; at the same time, the presence of the second sealing layer strengthens the isolation between the second coating and the external environment, which helps to maintain the integrity and functionality of the coating structure; it can also improve the quality of the coating surface, making the coating smoother and denser, improving its aesthetics and application performance; thereby enhancing the protective performance of the coating and extending its service life, which can reduce the need for regular inspections and repairs, thereby reducing the cost of long-term maintenance.

[0011] Furthermore, a bonding layer is also included, which is fixedly arranged between the first coating and the substrate and fixedly connects the first coating to the substrate. Through the arrangement of the bonding layer, a coating material with higher hardness can be used to form the coating, so that the wear resistance is stronger.

[0012] Furthermore, the material of the first sealing layer is an inorganic sealing agent. The entire spraying process is a high-temperature operation. The high-temperature stability of the inorganic sealing agent ensures that the first sealing layer will not be damaged in subsequent high-temperature operations, maintaining effective blocking of pores and avoiding protection failure caused by damage to the sealing layer; due to the stability of the inorganic sealing agent, the entire coating system can work better together and provide more reliable protection; a stable sealing layer means that the coating system requires less maintenance during its service life, reducing operating costs and improving economic benefits.

[0013] A method for manufacturing a thermal spray coating sealing structure comprises the following steps:

[0014] S1 pretreatment, treating the substrate surface so that the substrate surface meets the coating deposition conditions;

[0015] S2 sprays the first coating layer, depositing the first coating layer on the surface of the substrate pretreated in S1 to a designed thickness through a thermal spraying process;

[0016] S3: coating a first sealing layer, coating a first sealing solution on the surface of the first coating layer so that the first sealing solution penetrates into the gaps of the first coating layer and dries, so as to obtain a first sealing layer;

[0017] S4 sprays the second coating, after preheating the workpiece surface to a suitable temperature, a second coating is deposited on the surface of the first sealing layer treated in S3 to a designed thickness through a thermal spraying process to obtain the second coating.

[0018] Furthermore, the method further includes S5 coating a second sealing layer, coating a second sealing solution on the surface of the second coating layer so that the second sealing solution penetrates into the gaps of the second coating layer and dries, so as to obtain a first sealing layer.

[0019] Furthermore, S1 includes S11 surface pretreatment, S12 preheating and S13 surface treatment, wherein S11 surface pretreatment is: cleaning and decontaminating the workpiece surface and then roughening it by sandblasting; S12 preheating is: heating the workpiece treated by S11 to a suitable temperature; S13 surface treatment is: depositing a bonding layer on the surface of the workpiece treated by S12.

[0020] Furthermore, the preheating method in S12 and S4 may be electromagnetic induction heating or flame heating.

[0021] Furthermore, S3 coating of the first sealing layer includes S31 coating and S31 coating post-treatment, wherein S31 coating is: uniformly coating the first sealing solution on the coating surface; the coating method can be one of spraying, brushing or dipping; S32 coating post-treatment includes: standing for 1-2 minutes to allow the sealing solution to fully penetrate into the pores of the coating; using compressed gas to remove excess first sealing solution on the surface of the workpiece during S31 coating to accelerate drying, and after removing the excess first sealing solution, standing for 5-10 minutes.

[0022] Furthermore, the coating deposition method may be one of plasma spraying, supersonic flame spraying, flame spraying, arc spraying, and the like.

[0023] Through the above steps, this method not only achieves effective pore blocking, but also constructs a multi-layer protection system, which can significantly extend the service life of the coating and adapt to a variety of complex working environments; the design of each step takes into account the overall performance and long-term stability of the coating, ensuring the high quality and reliability of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the sealing structure of the present invention;

[0025] Figure 2 This is a statistical table of test results of an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The following is further described in detail through specific implementation methods:

[0027] The reference numerals in the embodiment include: substrate 1 , adhesive layer 21 , first coating layer 221 , second coating layer 222 , first sealing layer 231 , and second sealing layer 232 .

[0028] Example

[0029] The embodiment is basically as follows Figure 1-2 As shown, a thermal spray coating sealing structure and a manufacturing method thereof include a thermal spray coating sealing structure and a manufacturing method of the thermal spray coating sealing structure, such as Figure 1 As shown, a thermal spray coating sealing structure includes a bonding layer 21, a first coating 221, a second coating 222, a first sealing layer 231 and a second sealing layer 232. The bonding layer 21 is fixedly arranged between a substrate 1 and the first coating 221 and fixes the first coating 221 on the surface of the substrate 1. The first coating 221 and the second coating 222 constitute a coating body. The first sealing layer 231 is fixedly arranged between the first coating 221 and the second coating 222 and blocks the gaps in the first coating 221. The second sealing layer 232 is fixedly arranged on the outside of the second coating 222 and blocks the gaps in the second coating 222.

[0030] A method for manufacturing a thermal spray coating sealing structure comprises the following steps:

[0031] S1 pretreatment, treating the surface of the substrate 1, the treatment methods include S11 surface pretreatment, S12 preheating and S13 surface treatment, wherein S11 surface pretreatment is: cleaning and decontaminating the workpiece surface and then roughening it with sandblasting; S12 preheating is: heating the workpiece treated by S11 to a suitable temperature, the heating method can be electromagnetic induction heating or flame heating; S13 surface treatment is: depositing a bonding layer 21 on the surface of the workpiece treated by S12; so that the surface of the substrate 1 meets the coating deposition conditions;

[0032] S2 sprays the first coating 221, and deposits the first coating 221 on the surface of the substrate 1 pretreated in S1 to a designed thickness through a thermal spraying process;

[0033] S3 coating the first sealing layer 231, coating the first sealing solution on the surface of the first coating 221 so that the first sealing solution penetrates into the gaps of the first coating 221 and dries to obtain the first sealing layer 231, wherein S3 coating the first sealing layer 231 includes S31 coating and S31 coating post-treatment, wherein S31 coating is: uniformly coating the first sealing solution on the coating surface; the coating method can be one of spraying, brushing or dipping; S32 coating post-treatment includes: standing for 1-2 minutes to allow the sealing solution to fully penetrate into the pores of the coating; using compressed gas to remove excess first sealing solution on the surface of the workpiece during S31 coating to accelerate drying, and after removing the excess first sealing solution, standing for 5-10 minutes;

[0034] S4 sprays the second coating layer 222, and deposits the second coating layer 222 on the surface of the first sealing layer 231 treated in S3 to a designed thickness through a thermal spraying process;

[0035] S5 coats the second sealing layer 232. After preheating the workpiece surface to a suitable temperature, a second sealing solution is coated on the surface of the second coating 222 so that the second sealing solution penetrates into the gaps of the second coating 222 and dries. The coating method is the same as that in S31 coating to obtain the second sealing layer 232.

[0036] The bonding layer 21 , the first coating 221 and the second coating 222 may be deposited by plasma spraying, supersonic flame spraying, flame spraying, arc spraying or the like.

[0037] The corrosion resistance and wear resistance of the pore-sealing structure prepared in the present application will be described below in combination with specific examples and comparative examples.

[0038] Example 1 Preparation of aluminum oxide-titanium oxide coating on stainless steel surface

[0039] S1 preprocessing:

[0040] S11 surface pretreatment: first, the surface of the substrate 1 is cleaned and decontaminated, and the coating adhesion is enhanced by sandblasting roughening. In this example, the substrate 1 is a stainless steel workpiece.

[0041] S12 preheating: The surface of the stainless steel workpiece after S11 surface pretreatment is heated to a suitable temperature by electromagnetic induction heating or flame heating. In this example, the heating method is electromagnetic induction heating, and the heating temperature is 180 degrees.

[0042] S13 surface treatment: a layer of NiAl with a thickness of about 100 μm is deposited on the surface of the preheated stainless steel workpiece as a bonding layer 21 through a plasma spraying process; the spraying parameters are: argon main gas flow rate 45 L / min, helium auxiliary gas flow rate 30 L / min, current 500 A, spraying distance 100 mm, and gun moving speed 500 mm / s.

[0043] S2 spray first coating 221

[0044] After the pretreatment and the deposition of the bonding layer 21 are completed, a 100 μm thick aluminum oxide-titanium oxide ceramic coating is deposited thereon by a plasma spraying process as the first coating 221 ; the spraying parameters are the same as those of the bonding layer 21 .

[0045] S3 coating the first sealing layer 231

[0046] S31 coating: brushing the first sealing solution evenly on the surface of the first coating layer 221. In this example, the first sealing solution is a sodium silicate sealing solution.

[0047] S32 Post-coating treatment: Allow to stand for 2 minutes to allow the sealing solution to fully penetrate into the pores of the first coating 221; then use compressed gas to remove excess sealing solution to speed up the drying process, and then allow to stand for another 5-10 minutes.

[0048] S4 spray second coating 222

[0049] After preheating the workpiece surface to 180° C., the plasma spraying process is used again to continue spraying and depositing aluminum oxide-titanium oxide ceramic as the second coating 222 on the first sealing layer 231 until the total thickness reaches 250 μm (including the bonding layer 21 and the first coating 221 ).

[0050] S5: coating the second sealing layer 232. Finally, an organic Si sealing agent is coated on the surface of the second coating layer 222 as the second sealing layer 232. The specific operation is the same as the coating step S31.

[0051] Example 2: Example 2 is substantially the same as Example 1, except that Example 2 does not include the S5-coated second sealing layer 232 .

[0052] Comparative Example 1: Comparative Example 1 is substantially the same as Example 1, except that the first blocking layer is not provided in Comparative Example 1.

[0053] Comparative Example 2: Comparative Example 2 is substantially the same as Example 2, except that the first blocking layer is not provided in Comparative Example 2.

[0054] After the coating was made, the coating bonding strength and the self-corrosion potential and corrosion current before and after wear treatment were tested. The wear treatment method was: heat treatment at 400℃ for 6h and then grinding to 100μm. The test results are shown in Figure 2 .

[0055] Depend on Figure 2 It can be seen that the bonding strength of the coating prepared by the present application is basically the same as the bonding strength of the coating prepared by the traditional method, but after wear treatment, the self-corrosion potential and corrosion current of Example 1 and Example 2 are significantly lower than those of Comparative Example 1 and Comparative Example 2, that is, the corrosion resistance of the sealing structure of the present application after wear is significantly better than that of the prior art.

[0056] The above is only an embodiment of the present invention, and common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that the technical means for solving the problems in the above-mentioned embodiments of the present invention can be used in combination to solve multiple technical problems at the same time. For those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A thermal spray coating sealing structure, characterized in that: It includes a coating body formed by a thermal spraying process and a first sealing layer for sealing the gaps in the coating body. The coating body includes a first coating and a second coating. The first coating is fixedly connected to a substrate. The first sealing layer is fixedly arranged between the first coating and the second coating and fixes the second coating on the first coating.

2. The thermal spray coating sealing structure according to claim 1, characterized in that: It also includes a second sealing layer, which is fixedly arranged on a side of the second coating layer away from the first sealing layer and seals the gaps in the second coating layer.

3. The thermal spray coating sealing structure according to claim 2, characterized in that: The invention also comprises an adhesive layer, which is fixedly arranged between the first coating layer and the substrate and fixedly connects the first coating layer and the substrate.

4. The thermal spray coating sealing structure according to claim 3, characterized in that: The material of the first sealing layer is an inorganic sealing agent.

5. A method for manufacturing a thermal spray coating sealing structure, characterized in that: The steps include: S1 pretreatment, treating the substrate surface so that the substrate surface meets the coating deposition conditions; S2 sprays the first coating layer, depositing the first coating layer on the surface of the substrate pretreated in S1 to a designed thickness through a thermal spraying process; S3: coating a first sealing layer, coating a first sealing solution on the surface of the first coating layer so that the first sealing solution penetrates into the gaps of the first coating layer and dries, so as to obtain a first sealing layer; S4 sprays the second coating, after preheating the workpiece surface to a suitable temperature, a second coating is deposited on the surface of the first sealing layer treated in S3 to a designed thickness through a thermal spraying process to obtain the second coating.

6. The method for manufacturing a thermal spray coating sealing structure according to claim 7, characterized in that: The process also includes coating a second sealing layer in S5, coating a second sealing solution on the surface of the second coating layer so that the second sealing solution penetrates into the gaps of the second coating layer and dries, so as to obtain the second sealing layer.

7. The method for manufacturing a thermal spray coating sealing structure according to claim 7, characterized in that: The treatment in S1 includes S11 surface pretreatment, S12 preheating and S13 surface treatment, wherein S11 surface pretreatment is: cleaning and decontaminating the workpiece surface and then roughening it by sandblasting; S12 preheating is: heating the workpiece treated by S11 to a suitable temperature; S13 surface treatment is: depositing a bonding layer on the surface of the workpiece treated by S12.

8. The method for manufacturing a thermal spray coating sealing structure according to claim 7, characterized in that: The preheating method in S12 and S4 can be electromagnetic induction heating or flame heating.

9. The method for manufacturing a thermal spray coating sealing structure according to claim 7, characterized in that: S3 coating the first sealing layer includes S31 coating and S31 coating post-treatment, wherein S31 coating is: uniformly coating the first sealing solution on the coating surface; The coating method may be spraying, brushing or dipping; S32 post-coating treatment includes: standing for 1-2 minutes to allow the sealing solution to fully penetrate into the pores of the coating; Use compressed gas to remove excess first sealing solution on the surface of the workpiece during S31 coating to accelerate drying. After removing excess first sealing solution, let it stand for 5-10 minutes.

10. The method for manufacturing a thermal spray coating sealing structure according to claim 7, characterized in that: The deposition method may be one of plasma spraying, supersonic flame spraying, flame spraying, arc spraying, and the like.

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