Preparation method of gradient super-tough coating

Abstract

The invention discloses a preparation method of a gradient super-tough coating, which comprises the following steps: adopting a multi-spray-gun independent spraying cladding mode of different spraying materials, simultaneously spraying plastic components and strength enhancing components in the cladding process, gradually reducing the plastic components, and obtaining the gradient super-tough coating with gradually transitional components and uniform stress change. Particularly, the components of different components at different positions of the cladding layer are adjusted by adjusting the injection flow of the plastic component and the strength enhancing component in the cladding process, so that the gradient distribution of the super-tough coating is realized. According to the method, the composition and the structure gradient of the thermal spraying coating can be effectively controlled, smooth stress change in the solidification forming and using process is achieved, and therefore it is ensured that the high-toughness coating and the matrix structure are stably combined, the forming quality is improved, and the method is also suitable for preparing functionally graded materials.

Description

Technical Field

[0001] The invention belongs to the technical field of material processing, and in particular relates to a method for preparing a gradient ultra-tough coating. Background Art

[0002] In modern industrial applications, the surfaces of many parts require high hardness and strength to achieve excellent wear resistance. This improvement in wear resistance is not only necessary in terms of technology but also has good economic value.

[0003] The hardening of the metal surface was initially achieved through quenching, but the hardenability of a particular material has its limits. For example, the limit hardness of some high alloys is around HRC65, but in practical applications, many fields hope to achieve a hardness above HRC65. As a result, various cladding coating technologies have emerged, and hard materials are clad on the surface of the material to greatly improve the hardness and strength of the surface of the parts.

[0004] However, the stress transition and tissue bonding problems between the hardened layer and the matrix structure of thermal spraying in the prior art are difficult to solve in the case of single-gun spraying as the hardness requirements of the cladding layer increase. In particular, the materials of different components sprayed from the spray gun have different thermal expansion coefficients, and the cladding layer is more likely to crack when cooling. Therefore, it is necessary to form a strong and tough transition area at the cladding interface and area of ​​the material to reduce the stress concentration phenomenon during processing and use, thereby reducing the possibility of cracking and peeling of the cladding coating. For example, the stress distribution formed by forming a reasonable gradient in the composition distribution during the forming and use process is beneficial to the integrity of the cladding coating. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing a gradient ultra-tough coating. In the process of thermal spraying, a multi-spray gun with different spray materials is used for independent spraying cladding. In the cladding process, the plastic component and the strength enhancing component are sprayed simultaneously, and the plastic component is gradually reduced. Finally, a hardened coating with a gradual transition of components and a relatively uniform stress change is obtained, thereby solving the problem that while the thermal spraying technology greatly improves the hardness and strength of the cladding layer, the cladding layer is prone to cracking during preparation and use due to its high hardness and strength.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The present invention provides a method for preparing a gradient super-tough coating, comprising: adopting a multi-spray gun independent spray cladding method with different spray materials, spraying a plastic component and a strength enhancement component simultaneously during the cladding process, gradually reducing the plastic component, and obtaining a gradient super-tough coating with a gradual transition of components and uniform stress changes.

[0008] Preferably, during the cladding process, the composition of different components at different positions of the cladding layer is adjusted by adjusting the flow rates of the plastic component and the strength enhancement component to achieve a gradient distribution of the ultra-tough coating.

[0009] Preferably, the method for preparing the gradient ultra-tough coating comprises the following steps:

[0010] (a) Place the prefabricated parts at the process location and make process preparations;

[0011] (b) Different thermal coating spray guns are prepared and each is independently temperature-controlled;

[0012] (c) Using multiple spray guns with different spray materials to independently spray the cladding material;

[0013] (d) Starting from the spraying, different spray guns perform their respective flow control according to the predetermined program;

[0014] (e) Obtain a gradient ultra-tough coating with different composition gradients in different regions of the coating.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention prepares a gradient ultra-tough coating by independent spray cladding of multiple spray guns with different spray materials. An independent spray gun is used to spray materials with relatively good plasticity, and an independent spray gun is used to spray reinforcing phase materials. During the spray cladding process, the composition and proportion of different components at different positions of the cladding layer are adjusted by adjusting the spray flow rate to achieve a gradient distribution of the coating composition, thereby achieving high strength and toughness of the ultra-high strength coating.

[0017] 2. The present invention can effectively control the composition and organization gradient of the thermal spray coating, thereby achieving a gentle stress change during the solidification forming process and the use process, thereby ensuring a stable combination of the high-toughness coating and the matrix organization and improving the forming quality. In addition, the preparation method of the gradient super-tough coating in the present invention is also suitable for preparing functional gradient materials.

[0018] 3. The spraying temperatures of the independent spray guns in the present invention are different, which is beneficial to reducing the thermal cracks caused by the different expansion coefficients of different components during solidification, thereby controlling and facilitating the formation of fine equiaxed crystal structure. DETAILED DESCRIPTION

[0019] In order to more fully understand and demonstrate the technical solutions, purposes and advantages of the present invention, the technical effects produced by the present invention are further described in detail and completely in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all. It should be pointed out that for those of ordinary skill in the art, other embodiments obtained without departing from the concept of the present invention all belong to the protection scope of the present invention.

[0020] A method for preparing a gradient ultra-tough coating is proposed in the following embodiment, including: using multiple spray guns with different spray materials to independently spray and clad, spraying plastic components and strength enhancement components simultaneously during the cladding process, gradually reducing the plastic component, and obtaining a gradient ultra-tough coating with gradual component transition and uniform stress change.

[0021] In some embodiments, during the cladding process, the composition of different components at different positions of the cladding layer is adjusted by adjusting the flow rates of the plastic component and the strength enhancement component to achieve a gradient distribution of the ultra-tough coating.

[0022] In some embodiments, the method for preparing the gradient ultra-tough coating comprises the following steps:

[0023] (a) Place the prefabricated parts at the process location and make process preparations;

[0024] (b) Different thermal coating spray guns are prepared and each is independently temperature-controlled;

[0025] (c) Using multiple spray guns with different spray materials to independently spray the cladding material;

[0026] (d) Starting from the spraying, different spray guns perform their respective flow control according to the predetermined program;

[0027] (e) Obtain a gradient ultra-tough coating with different composition gradients in different regions of the coating.

[0028] Example 1

[0029] In this embodiment, a gradient ultra-tough coating is prepared by a double-gun cladding method, and the specific steps are as follows:

[0030] (1) After pretreatment, INCONEL 625 nickel-based alloy parts are placed in the predetermined spraying position.

[0031] (2) The heat source spray guns are prepared and debugged. One heat spray gun sprays the melted nickel-based alloy powder, and the spray temperature is controlled at 1460°C; the other heat spray gun sprays 10000 mesh fine corundum powder, and the temperature is controlled at 1350°C.

[0032] (3) When spraying begins, the flow rate of the nickel-based melt spray gun is 4 times that of the corundum spray gun. During the spraying process, the flow rate of the nickel-based alloy spray gun decreases continuously and eventually drops to 0, while the flow rate of the corundum spray gun increases gradually.

[0033] (4) After the spraying is completed, a corundum gradient coating with a hard surface and excellent toughness is formed.

[0034] Comparative Example 1

[0035] (1) After pretreatment, INCONEL 625 nickel-based alloy parts are placed in the predetermined spraying position.

[0036] (2) The heat source spray gun is prepared and debugged. The heat spray gun sprays 10000 mesh fine corundum powder and the temperature is controlled at 2000℃.

[0037] (3) Spray fine corundum powder onto the pretreated surface of nickel-based alloy parts using a thermal spray gun.

[0038] Table 1: Comparison of hardness and structure observation

[0039]

[0040] As can be seen from Table 1, double-gun thermal spraying can obtain a gradient super-tough coating with good formability, while single-gun spraying of corundum powder has higher strength but poor formability.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a gradient ultra-tough coating, characterized in that: include: The cladding method is adopted in which multiple spray guns with different spray materials are used to independently spray. During the cladding process, the plastic component and the strength enhancement component are sprayed simultaneously, and the plastic component is gradually reduced to obtain a gradient ultra-tough coating with gradual transition of components and uniform stress change.

2. The method for preparing the gradient super-tough coating according to claim 1, characterized in that: By adjusting the flow rate of the plastic component and the strength enhancement component during the cladding process, the composition of different components at different positions of the cladding layer can be adjusted to achieve a gradient distribution of the ultra-tough coating.

3. The method for preparing the gradient super-tough coating according to claim 1 or 2, characterized in that: The preparation method of the gradient ultra-tough coating comprises the following steps: (a) Place the prefabricated parts at the process location and make process preparations; (b) Different thermal coating spray guns are prepared and each is independently temperature-controlled; (c) Using multiple spray guns with different spray materials to independently spray the cladding material; (d) Starting from the spraying, different spray guns perform their respective flow control according to the predetermined program; (e) Obtain a gradient ultra-tough coating with different composition gradients in different regions of the coating.

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