A composite anti-stick coating, a coating roller, its preparation method and applications

Abstract

A composite anti-adhesion coating, a coating roller and a preparation method and use thereof; the preparation method comprises the following steps: (1) mixing Ni powder and Al powder, the volume ratio of the Ni powder and the Al powder being 1:(0.1-10); the particle size of the Ni powder and the Al powder being 5-150 mu m; (2) preparing a Ni-Al composite coating with a thickness of 100-500 mu m on the surface of a steel material by depositing the mixed powder of step (1) through a cold spraying method; (3) placing the Ni-Al composite coating in 500-600 DEG C and keeping warm; (4) removing Al in the coating by immersing the Ni-Al composite coating in a corrosion solution to obtain a porous coating structure; (5) applying an anti-adhesion high molecular liquid to the porous coating structure to obtain a composite anti-adhesion coating. The scheme can improve the strength of the anti-adhesion coating and the bonding degree on the steel material, thereby solving the problems of low strength and easy wear and fall of the organic anti-adhesion high molecular coating.

Description

Technical Field

[0001] This invention relates to the field of anti-stick composite coatings, and more particularly to a composite anti-stick coating, a coating roller, a preparation method thereof, and its applications. Background Technology

[0002] Coating rollers are primarily used to transfer coating liquid to the surface of the object to be coated. The roller surface of the coating roller has high requirements for anti-stick properties. Generally, fluorinated polymers (such as PTFE) and silicon-containing polymers (such as PDMS) are commonly used organic polymer anti-stick coatings for existing coating rollers. This is mainly due to the low surface energy and chemical stability of these polymers, which achieves the anti-stick effect on the coating roller. Furthermore, this anti-stick coating is widely used in various working conditions, such as in the textile, fine chemical, and petroleum industries.

[0003] Compared to inorganic materials, one of the biggest drawbacks of organic polymer anti-stick coatings is their lower strength. For example, filling Teflon polymers with other reinforcing materials (such as carbon nanotubes, silica, alumina particles, etc.) is a common method to improve strength. However, since the particulate reinforcing phase is only dispersed in the Teflon emulsion, it cannot form a continuous structure during curing, making it difficult to fundamentally improve the coating strength. Another example is the preparation of Ni-P coatings via electroplating, where PTFE emulsion is added to the plating bath to achieve PTFE particle deposition in the Ni-P coating. However, the PTFE particles in the composite coating prepared by this method are easily worn away, making long-term application difficult. Thus, existing organic anti-stick polymer coatings suffer from low strength and easy wear and detachment. Summary of the Invention

[0004] The purpose of this invention is to propose a method for preparing a composite anti-stick coating. First, Ni powder and Al powder of a specific particle size are mixed in a certain volume ratio to make the porosity of the Ni-Al composite coating 10-50%. Then, an anti-stick polymer liquid is applied to the obtained NiAl alloy skeleton, which can improve the strength of the anti-stick coating and its adhesion to steel.

[0005] The present invention also proposes a method for preparing a coating roller, wherein a Ni-Al composite coating with a thickness of 100-500 μm is prepared on the roller surface of the coating roller by a cold spraying method.

[0006] The present invention also proposes a composite anti-stick coating, which includes: a steel layer, a Ni-Al composite coating and an anti-stick polymer layer.

[0007] The present invention also proposes a coating roller, the roller surface of which is provided with a composite anti-stick coating prepared by the above preparation method.

[0008] The present invention also proposes the use of a coating in the preparation of steel with anti-stick properties.

[0009] The present invention also proposes the use of a coating in the preparation of coating rollers.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] A method for preparing a composite anti-stick coating includes the following steps:

[0012] (1) Mix Ni powder and Al powder, with a volume ratio of Ni powder to Al powder of 1:(0.1~10); the particle size of Ni powder and Al powder is 5~150μm, so that the porosity of the Ni-Al composite coating in step (2) is 10~50%.

[0013] (2) A Ni-Al composite coating with a thickness of 100-500 μm is prepared by depositing the mixed powder from step (1) onto the surface of steel using a cold spraying method.

[0014] (3) Keep the Ni-Al composite coating at 500-600℃;

[0015] (4) Immerse the Ni-Al composite coating from step (3) in a corrosion solution to remove Al from the coating and obtain a porous coating structure; clean and dry the Ni-Al composite coating.

[0016] (5) Apply the anti-sticking polymer liquid to the porous coating structure in step (4), and dry and / or cure the anti-sticking polymer liquid to obtain a composite anti-sticking coating.

[0017] Preferably, in step (5), the PTFE polymer emulsion is sprayed onto the porous coating structure of step (4) with compressed air at 0.6-0.8 MPa, and the PTFE polymer emulsion is dried and cured to obtain a NiAl-PTFE composite anti-stick coating.

[0018] Preferably, in step (5), the PDMS solution is coated into the porous coating structure of step (4), dried and cured to obtain a NiAl-PDMS composite anti-stick coating.

[0019] Preferably, in step (4), the Ni-Al composite coating from step (3) is immersed in a 4-6 mol / L NaOH solution for 10-14 h to obtain a porous coating structure.

[0020] A method for preparing a coating roller includes the above-mentioned method for preparing a composite anti-stick coating;

[0021] In step (2), a Ni-Al composite coating with a thickness of 100-500 μm is prepared by depositing the mixed powder from step (1) onto the surface of the coating roller using a cold spraying method.

[0022] A composite anti-stick coating is prepared by the above-mentioned method for preparing a composite anti-stick coating, and comprises, from bottom to top: a steel layer, a Ni-Al composite coating and an anti-stick polymer layer;

[0023] The porosity of the Ni-Al composite coating is 10-50%; the thickness of the Ni-Al composite coating is 100-500 μm.

[0024] Preferably, the anti-stick polymer layer comprises: a PTFE anti-stick coating or a PDMS anti-stick coating.

[0025] A coating roller having a composite anti-stick coating; the composite anti-stick coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0026] The use of a coating in the preparation of steel with anti-stick function, wherein the coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0027] The use of a coating in the preparation of a coating roller, wherein the coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0028] Compared with the prior art, one of the above technical solutions has the following beneficial effects:

[0029] This solution provides a method for preparing a composite anti-stick coating. First, Ni powder and Al powder of a specific particle size are mixed in a certain volume ratio to make the porosity of the Ni-Al composite coating 10-50%. Then, an anti-stick polymer liquid is applied to the obtained NiAl alloy skeleton, which can improve the strength of the anti-stick coating and its adhesion to steel, thereby solving the problems of low strength and easy wear and peeling of organic anti-stick polymer coatings. Attached Figure Description

[0030] Figure 1 This is the cross-sectional morphology of the coating in Example A1;

[0031] Figure 2 This is the cross-sectional morphology of the coating in Example A2;

[0032] Figure 3 This is the cross-sectional morphology of the coating in Example A3;

[0033] Figure 4 This is the cross-sectional morphology of the coating in Example A4;

[0034] Figure 5 This is a schematic diagram of the anti-sticking test in Example A4;

[0035] Figure 6This is a schematic diagram of the anti-sticking test in Example A4;

[0036] Figure 7 This is the cross-sectional morphology of the coating in Example B;

[0037] Figure 8 This is a schematic diagram of the anti-sticking test in Example B;

[0038] Figure 9 This is a schematic diagram of the anti-sticking test in Example B;

[0039] Figure 10 This is a schematic diagram of the coating adhesion test of the NiAl-PTFE composite anti-stick coating;

[0040] Figure 11 This is a schematic diagram of the coating adhesion test of the NiAl-PDMS composite anti-stick coating; Detailed Implementation

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0042] A method for preparing a composite anti-stick coating includes the following steps:

[0043] (1) Mix Ni powder and Al powder, with a volume ratio of Ni powder to Al powder of 1:(0.1~10); the particle size of Ni powder and Al powder is 5~150μm, so that the porosity of the Ni-Al composite coating in step (2) is 10~50%.

[0044] This scheme uses Ni powder and Al powder to prepare a Ni-Al composite coating, which can be deposited on the steel surface. Furthermore, by adjusting the volume ratio of Ni powder to Al powder to 1:(0.1~10) and the particle size to 5~150μm, the porosity of the Ni-Al composite coating can be adjusted. At this porosity, the Ni-Al composite coating exhibits stable adhesion to the steel and can stably support the anti-adhesion polymer layer. In this scheme, if the porosity is too low, it cannot provide enough space for loading polymer materials; if the porosity is too high, the NiAl skeleton cannot be effectively bonded, resulting in insufficient strength of the porous structure.

[0045] (2) A Ni-Al composite coating with a thickness of 100-500 μm is prepared by depositing the mixed powder from step (1) onto the surface of steel using a cold spraying method.

[0046] Cold spraying is a known process. In this application, cold spraying can be used to apply a mixture of Ni and Al powders to steel at room temperature or a lower temperature using a supersonic gas-solid two-phase gas flow to form a dense coating. Therefore, it does not involve high-temperature heating of powder particles, and thus avoids effects such as high-temperature oxidation, vaporization, melting, and crystallization that affect the coating performance, ensuring the structural stability of the Ni-Al composite coating. In this application, a nitrogen and helium mixture of 3-5 MPa can be preferentially used as the carrier gas during the preparation process, with a spraying distance of 40-60 mm and a powder feed rate of 30-60 g / min.

[0047] The steel used can be any known type, but this solution preferably uses 45# steel, Q235 steel, or 316L stainless steel. The optimal thickness of the Ni-Al composite coating is 100–500 μm, which can be 100 μm, 200 μm, 300 μm, 400 μm, or 500 μm. Too thin a thickness may lead to structural instability of the Ni-Al composite coating; too thick a thickness may lead to a decrease in the adhesion to the anti-sticking polymer liquid.

[0048] (3) Keep the Ni-Al composite coating at 500-600℃;

[0049] After holding at 500-600℃ for a period of time, such as 3-5 hours, Al continuously diffuses into Ni to form partial NiAl, while simultaneously achieving inter-phase bonding between the Ni and Al phases. This creates a NiAl alloy skeleton in the coating and initially forms a porous structure. The holding equipment can be an electric furnace.

[0050] (4) Immerse the Ni-Al composite coating from step (3) in a corrosion solution to remove Al from the coating and obtain a porous coating structure; clean and dry the Ni-Al composite coating.

[0051] The Ni-Al composite coating has initially formed a porous structure in step (3). The corrosion solution can remove some of the Al in the Ni-Al composite coating and dissolve the Al in the NiAl alloy skeleton through chemical dissolution, thereby further increasing the number of pores in the porous structure formed in step (3). After the porous coating structure has been corroded, it can be washed with deionized water to remove free Al and corrosion solution.

[0052] (5) Apply the anti-sticking polymer liquid to the porous coating structure in step (4), and dry and / or cure the anti-sticking polymer liquid to obtain a composite anti-sticking coating.

[0053] The anti-stick polymer liquid can be replaced by a known polymer material with anti-stick function, such as PTFE polymer emulsion or PDMS solution; the anti-stick polymer liquid adheres to the NiAl alloy skeleton and forms a continuous film structure after curing, which is not easy to fall off after wear.

[0054] This solution provides a method for preparing a composite anti-stick coating. First, Ni powder and Al powder of a specific particle size are mixed in a certain volume ratio to make the porosity of the Ni-Al composite coating 10-50%. Then, an anti-stick polymer liquid is applied to the obtained NiAl alloy skeleton, which can improve the strength of the anti-stick coating and its adhesion to steel, thereby solving the problems of low strength and easy wear and peeling of organic anti-stick polymer coatings.

[0055] Preferably, in step (5), the PTFE polymer emulsion is sprayed onto the porous coating structure of step (4) with compressed air at 0.6-0.8 MPa, and the PTFE polymer emulsion is dried and cured to obtain a NiAl-PTFE composite anti-stick coating.

[0056] PTFE is polytetrafluoroethylene. Existing PTFE particles are deposited in Ni-P coatings by electroplating. In this application, PTFE polymer emulsion is attached to the NiAl alloy skeleton. The NiAl alloy skeleton can improve the adhesion of PTFE in the coating. Moreover, it is a continuous structure, which is not easy to wear and is less likely to fall off.

[0057] Preferably, in step (5), the PDMS solution is coated into the porous coating structure of step (4), dried and cured to obtain a NiAl-PDMS composite anti-stick coating.

[0058] PDMS is polydimethylsiloxane; in this application, PDMS solution is attached to a NiAl alloy skeleton, which can improve the adhesion of PDMS in the coating. Moreover, the continuous structure makes it less prone to wear and detachment.

[0059] Preferably, in step (4), the Ni-Al composite coating from step (3) is immersed in a 4-6 mol / L NaOH solution for 10-14 h to obtain a porous coating structure.

[0060] The concentration of the NaOH solution can be determined as needed; however, in the optimal embodiment of this scheme, the Ni-Al composite coating is immersed in a 4-6 mol / L NaOH solution, which results in the optimal number and stability of pores on the surface of the porous coating structure. For example, it can be immersed in a 5 mol / L NaOH solution for 12 hours.

[0061] A method for preparing a coating roller includes the above-mentioned method for preparing a composite anti-stick coating;

[0062] In step (2), a Ni-Al composite coating with a thickness of 100-500 μm is prepared by depositing the mixed powder from step (1) onto the surface of the coating roller using a cold spraying method.

[0063] When a coating roller transfers coating liquid to the surface of an object to be coated, it has high requirements for anti-sticking properties. This solution preferably prepares a Ni-Al composite coating directly on the surface of the coating roller, so that the anti-sticking polymer liquid adheres through the Ni-Al composite coating. The anti-sticking performance meets the anti-sticking requirements of the coating roller and also meets the requirement that the anti-sticking coating is not easy to fall off during the coating process.

[0064] A composite anti-stick coating is prepared by the above-mentioned method for preparing a composite anti-stick coating, and comprises, from bottom to top: a steel layer, a Ni-Al composite coating and an anti-stick polymer layer;

[0065] The porosity of the Ni-Al composite coating is 10-50%; the thickness of the Ni-Al composite coating is 100-500 μm.

[0066] Preferably, the anti-stick polymer layer comprises: a PTFE anti-stick coating or a PDMS anti-stick coating.

[0067] A coating roller having a composite anti-stick coating; the composite anti-stick coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0068] The use of a coating in the preparation of steel with anti-stick function, wherein the coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0069] The use of a coating in the preparation of a coating roller, wherein the coating is prepared by the above-described method for preparing a composite anti-stick coating, or is a composite anti-stick coating as described above.

[0070] Performance testing:

[0071] Coating structure: The coating cross-section sample was cut, and a metallographic sample was prepared using phenolic thermal mounting material. The coating condition was observed using a metallographic microscope.

[0072] Anti-stick properties: Heat PET to a molten state, take a piece of steel with a composite anti-stick coating, attach PET to the steel, and if the PET falls off naturally after cooling, it is qualified.

[0073] Coating adhesion: The adhesion of steel with composite anti-stick coating was tested according to GB 1720-1979 Test Method for Coating Adhesion.

[0074] Example A: Perform the following examples A1-A4 respectively;

[0075] Example A1:

[0076] (1) Ni powder and Al powder are mixed, with a volume ratio of 1:2; the particle size of Ni powder and Al powder is 60μm, so that the porosity of the Ni-Al composite coating in step (2) is 20%.

[0077] (2) A Ni-Al composite coating with a thickness of 500 μm is prepared by depositing the mixed powder from step (1) on the surface of steel using a cold spraying method.

[0078] The performance of the Ni-Al composite coating in Example A1 was tested, and the results are as follows: Figure 1 As shown; Figure 1 The dark area is Ni and the light area is Al; this illustrates that after cold spraying in step (2), Ni powder and Al powder are applied to the steel to form a dense coating.

[0079] Example A2:

[0080] Based on steps (1) to (2) of embodiment A1, the following steps are performed:

[0081] (3) Place the Ni-Al composite coating in an electric furnace at 550℃ and keep it warm for 4 hours.

[0082] The performance of the Ni-Al composite coating in Example A2 was tested. The results are as follows: Figure 2 As shown; Figure 2 The heat-treated Ni-Al composite coating initially exhibits a porous structure. Figure 2 The circled area represents the solid solution formation of the NiAl alloy framework. This illustrates that during the heat treatment in the electric furnace, the Ni and Al phases interconnect at 500-600℃, forming the NiAl alloy framework within the coating and initially creating the porous structure of the coating.

[0083] Example A3:

[0084] Based on steps (1) to (3) of embodiment A2, the following steps are performed:

[0085] (4) Immerse the Ni-Al composite coating from step (3) in a 5 mol / L NaOH solution for 12 h to obtain a porous coating structure; clean and dry the Ni-Al composite coating.

[0086] The performance of the Ni-Al composite coating in Example A3 was tested. The results are as follows: Figure 3 As shown; Figure 3After 12 hours of etching with NaOH solution, the Ni-Al composite coating exhibited a porous structure. The pores in Example A3 were more numerous and larger in size than those in Example A2. This demonstrates that using an etching solution to dissolve some of the Al in the Ni-Al composite coating can further increase the number and size of the porous structure in step (3).

[0087] Example A4:

[0088] Based on steps (1) to (4) of embodiment A3, perform the following steps:

[0089] (5) The PTFE polymer emulsion is sprayed into the porous coating structure of step (4) with compressed air at 0.7MPa, and the PTFE polymer emulsion is dried and cured at 350℃ to obtain NiAl-PTFE composite anti-stick coating.

[0090] The NiAl-PTFE composite anti-stick coating of Example A4 was subjected to performance tests on coating structure, anti-stick properties, and coating adhesion. The coating structure results are as follows: Figure 4 As shown, the anti-stick performance test is as follows: Figure 5-6 As shown; Figure 4 In this process, the PTFE polymer emulsion cures to form a PTFE anti-stick coating, which adheres to the porous structure of the NiAl alloy skeleton. Based on the distribution of the PTFE anti-stick coating on the NiAl alloy skeleton, the PTFE anti-stick coating has formed a continuous film structure. This demonstrates that the NiAl alloy skeleton in this solution can enable the anti-stick polymer liquid to form a continuous film structure after curing, and the continuous bonding between the NiAl alloy skeleton and the PTFE anti-stick coating will inevitably improve the strength of the composite anti-stick coating.

[0091] At the same time, by Figure 5 and Figure 6 It can be seen that the NiAl-PTFE composite anti-stick coating of this solution has excellent anti-stick properties. Figure 5 In the middle, the workpiece is covered with heated and molten PET; Figure 6 In the process, PET can be easily separated from the workpiece after cooling, which demonstrates the anti-sticking effect of the NiAl-PTFE composite anti-stick coating.

[0092] like Figure 10 It can be seen that after the NiAl-PTFE composite anti-stick coating is gridded, no grid on the surface of the coating is cracked or peeled off, indicating that the adhesion can reach level 0.

[0093] Example B:

[0094] Based on steps (1) to (4) of embodiment A3, perform the following steps:

[0095] (5) The PDMS solution is coated into the porous coating structure of step (4) and dried and cured at 110°C to obtain the NiAl-PDMS composite anti-stick coating.

[0096] The NiAl-PDMS composite anti-stick coating of Example B was subjected to coating structure and anti-stick performance tests. The coating structure results are as follows: Figure 7 As shown, the anti-stick performance test is as follows: Figure 8-9 As shown; Figure 7 In this process, after the PDMS solution cures, a PDMS anti-stick coating is formed, which adheres to the porous structure of the NiAl alloy skeleton. Based on the distribution of the PDMS anti-stick coating on the NiAl alloy skeleton, the PDMS anti-stick coating has formed a continuous film structure. This demonstrates that the NiAl alloy skeleton of this solution can enable the anti-stick polymer liquid to form a continuous film structure after curing, and the continuous combination of the NiAl alloy skeleton and the PDMS anti-stick coating will inevitably improve the strength of the composite anti-stick coating.

[0097] At the same time, by Figure 8-9 It can be seen that the NiAl-PDMS composite anti-stick coating of this solution has excellent anti-stick properties. Figure 8 In the process, a workpiece with a NiAl-PDMS composite anti-stick coating is attached to heated and molten PET. Figure 9 In the process, PET easily separated from the workpiece after cooling, thus demonstrating the anti-sticking effect of the NiAl-PDMS composite anti-stick coating.

[0098] like Figure 11 It can be seen that after the NiAl-PDMS composite anti-stick coating is gridded, no grid on the surface of the coating is cracked or peeled off, indicating that the adhesion can reach level 0.

[0099] Example C:

[0100] (1) Ni powder and Al powder are mixed, with a volume ratio of 9:1; the particle size of Ni powder is 5 μm; the particle size of Al powder is 40 μm, so that the porosity of the Ni-Al composite coating in step (2) is 10%.

[0101] (2) A Ni-Al composite coating with a thickness of 100 μm is prepared by depositing the mixed powder from step (1) on the surface of steel using a cold spraying method.

[0102] (3) Place the Ni-Al composite coating in an electric furnace at 600℃ and keep it warm for 3.5 hours.

[0103] (4) Immerse the Ni-Al composite coating from step (3) in a 5 mol / L NaOH solution for 12 h to obtain a porous coating structure; clean and dry the Ni-Al composite coating.

[0104] (5) The PTFE polymer emulsion is sprayed into the porous coating structure of step (4) with compressed air at 0.6 MPa, and the PTFE polymer emulsion is dried and cured at 350°C to obtain the NiAl-PTFE composite anti-stick coating.

[0105] Example D:

[0106] (1) Ni powder and Al powder are mixed, with a volume ratio of 1:1; the particle size of Ni powder is 80 μm; the particle size of Al powder is 80 μm, so that the porosity of the Ni-Al composite coating in step (2) is 50%.

[0107] (2) A Ni-Al composite coating with a thickness of 400 μm is prepared by depositing the mixed powder from step (1) on the surface of steel using a cold spraying method.

[0108] (3) Place the Ni-Al composite coating in an electric furnace at 500℃ and keep it warm for 5 hours.

[0109] (4) The Ni-Al composite coating from step (3) was immersed in a 5.5 mol / L KOH solution for 11 h to obtain a porous coating structure; the Ni-Al composite coating was then cleaned and dried.

[0110] (5) The PDMS solution is coated into the porous coating structure of step (4) and dried and cured at 110°C to obtain the NiAl-PDMS composite anti-stick coating.

[0111] Example E:

[0112] (1) Ni powder and Al powder are mixed, with a volume ratio of Ni powder to Al powder of 1:9; the particle size of Ni powder is 50 μm; the particle size of Al powder is 5 μm, so that the porosity of the Ni-Al composite coating in step (2) is 10%.

[0113] (2) A Ni-Al composite coating with a thickness of 200 μm is prepared by depositing the mixed powder from step (1) on the surface of steel using a cold spraying method.

[0114] (3) Place the Ni-Al composite coating in an electric furnace at 600℃ and keep it warm for 4 hours.

[0115] (4) Immerse the Ni-Al composite coating from step (3) in a 6 mol / L NaOH solution for 10 h to obtain a porous coating structure; clean and dry the Ni-Al composite coating.

[0116] (5) The PTFE polymer emulsion is sprayed into the porous coating structure of step (4) with compressed air at 0.7MPa, and the PTFE polymer emulsion is dried and cured at 350℃ to obtain NiAl-PTFE composite anti-stick coating.

[0117] The NiAl-PTFE composite anti-stick coatings of Examples C-E were subjected to anti-sticking tests and coating adhesion tests, and the results are shown in Table 1.

[0118] Table 1 - Anti-stick properties of CE in Example 1

[0119] Test Project Example C Example D Example E Non-stick qualified qualified qualified Coating adhesion Level 0 Level 0 Level 0

[0120] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for producing a composite release coating, characterized by, The method comprises the following steps: (1) mixing Ni powder and Al powder, the volume ratio of the Ni powder and the Al powder being 1:(0.1-10), and the particle size of the Ni powder and the Al powder being 5-150 μm, so that the porosity of the Ni-Al composite coating is 10-50%; (2) depositing the mixed powder of step (1) on the surface of a steel material by a cold spraying method to prepare a Ni-Al composite coating with a thickness of 100-500 μm; (3) placing the Ni-Al composite coating in a 500-600 ℃ heat preservation furnace; (4) immersing the Ni-Al composite coating of step (3) in a corrosion solution to remove part of the Al in the coating, so as to obtain a porous coating structure; cleaning and drying the Ni-Al composite coating; (5) applying a non-stick polymer liquid to the porous coating structure of step (4), drying and / or curing the non-stick polymer liquid, and obtaining a composite non-stick coating; when the non-stick polymer liquid is a polytetrafluoroethylene (PTFE) polymer emulsion, spraying the polytetrafluoroethylene (PTFE) polymer emulsion on the porous coating structure of step (4) under a pressure of 0.6-0.8 MPa of compressed air, drying and curing the polytetrafluoroethylene (PTFE) polymer emulsion, and obtaining a NiAl-PTFE composite non-stick coating; when the non-stick polymer liquid is a polydimethylsiloxane (PDMS) solution, coating the polydimethylsiloxane (PDMS) solution on the porous coating structure of step (4), drying and curing, and obtaining a NiAl-PDMS composite non-stick coating.

2. A method of preparing a composite release coating according to claim 1, characterized in that, In step (4), the Ni-Al composite coating of step (3) is immersed in a 4-6 mol / L NaOH solution for 10-14 h, so as to obtain a porous coating structure.

3. A method of producing a coating roll, characterized by The preparation method of a composite non-stick coating according to any one of claims 1-2; In step (2), the mixed powder of step (1) is deposited on the surface of a coating roller by a cold spraying method to prepare a Ni-Al composite coating with a thickness of 100-500 μm.

4. Use of a coating in the preparation of a steel material with a non-stick function, wherein the coating is prepared by the preparation method of a composite non-stick coating according to any one of claims 1-2.

5. Use of a coating in the preparation of a coating roller, wherein the coating is prepared by the preparation method of a composite non-stick coating according to any one of claims 1-2.

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