Preparation method of composite metal alloy coating layer and spraying equipment

[0037] In order to make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved more clear, the technical solutions of the present invention will be further described below with reference to the drawings and specific implementations. It can be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for ease of description, the drawings only show parts related to the present invention, but not all.

[0038] At present, surface engineering technologies include vacuum coating, vacuum sputtering, and vacuum electroplating. The technology of applying stainless steel powder as a coating on the substrate. The above three methods have the possibility of easy peeling of the coating, high requirements on the target material, and pollution. defect. Therefore, this embodiment provides a spraying method to spray stainless steel powder on the surface of the substrate to achieve the purpose of enhancing the surface performance.

[0039] In the method for preparing a composite metal alloy coating layer proposed in this embodiment, the composite metal alloy coating layer includes a first coating and a second coating that are connected, and the preparation method sequentially includes steps 1), 2), and steps 3), step 1) is to use Cu alloy, Al alloy or Zn alloy as the thermal spraying raw material powder, and spray the thermal spraying raw material powder in the molten state to the surface of the pretreated substrate at a first preset speed to form the The first coating; step 2) is to put the stainless steel powder in an oven for no less than 2 hours to demagnetize the stainless steel powder; step 3) is to use the demagnetized stainless steel powder as the cold spray raw material powder, The cold spray raw material powder is sprayed to the outer surface of the first coating at a second preset speed to form a second coating. Use step 1) to spray Cu alloy, Al alloy or Zn alloy on the surface of the substrate to form a first coating with plastic deformation properties, and then spray stainless steel powder on the outer surface of the first coating by cold spraying to form The second coating with a denser surface and better surface quality improves the surface performance of the substrate.

[0040] Such as figure 1 Shown is a schematic diagram of the working state of the second coating provided by this embodiment, including a spray gun 1 and a workbench. A substrate 2 is placed on the workbench. The first coating has been sprayed on the substrate 2 by thermal spraying. The spray gun 1 There are stainless steel powder raw materials to be cold sprayed. The stainless steel powder raw material is sprayed on the surface of the first coating 4 in the form of a high-speed particle stream 3 through the spray gun 1 to form the second coating.

[0041] Specifically, first, using an electric arc or a plasma arc as a heat source, the powdery or filamentary Cu alloy, Al alloy or Zn alloy raw material is atomized by the high-speed airflow formed by the spray gun 1, and sprayed at a certain speed to the pretreatment The first coating layer 4 is formed on the surface of the substrate 2; then the powdered stainless steel powder is sprayed to the first coating layer 4 at a high speed through the spray gun 1, thereby forming the second coating layer. At this time, the second coating layer It is denser than the first coating 4.

[0042] In this embodiment, in order to obtain a higher spray speed for the thermal spraying raw material powder and the cold spraying raw material powder, the working air pressure of the spray gun 1 is 0.6-2.0 MPa, so that the first preset speed and the second preset speed are 600m/s~700m/s. Preferably, the speed value of the first preset speed and the second preset speed is 680 m/s.

[0043] In thermal spraying, the composition and content of Cu alloy, Al alloy or Zn alloy used are:

[0044] The composition of Cu alloy includes: Cu, Zn, P, CuO, Sn, among them, Cu: 92%-96%; Zn: 2%-6%; CuO: 0.5%-3%; P: 0.1%-0.5%; Sn: 0.01%~2%;

[0045] The composition of Al alloy includes: Al, Al2O3, Fe, Mg, Si, among which, AL: 90%-95%; Al2O3: 3%-5%; Fe: 0.1%-2%; Mg: 0.02%-0.4%; Si: 0.05%~0.1%;

[0046] The composition of Zn alloy includes: Zn and ZnO, among which Zn: 95% to 98%; ZnO: 2% to 5%.

[0047] First, heat the thermal spraying raw material powder to a molten state with an initial temperature of 1200°C to 2700°C, and then spray the thermal spraying raw material powder to the surface of the substrate 2 through the spray gun 1 at a temperature of 20°C to 80°C. In order to adapt to the substrate 2 of different materials, it is necessary to control the temperature at which the thermal spray powder reaches the surface of the substrate 2 to prevent scratches on the surface of the substrate 2. In this embodiment, the material of the base material 2 includes plastic, glass, ceramic, metal, corundum or cotton material. Taking the material of base material 2 as plastic as an example, the melting point of the plastic material (polyethylene) is between 120°C and 136°C. During thermal spraying, the raw material powder for thermal spraying needs to be heated to 1200°C to 2700°C. In the process of raw materials reaching the surface of the plastic material, in order not to damage the quality of the substrate surface, the temperature of the thermal spraying raw materials needs to be controlled at 20°C to 80°C to avoid high-temperature thermal spraying raw materials from damaging the flatness of the substrate surface.

[0048] When cold spraying, the composition and content of each component of the stainless steel powder used are:

[0049] The composition of stainless steel powder includes: Fe, Ni, Cr, Cu, P, S, Mo; Among them, Fe: 65%~68%; Ni: 7%~10%; Cr: 14%~19%; Cu: 1% ~5%; C: 0~0.2%, P: 0~0.1%, S: 0~0.2%.

[0050] In addition, the particle radius of the stainless steel powder is 0.002 mm to 0.030 mm, preferably the particle size of the stainless steel powder and the content of each composition component, which can effectively improve the adhesion ability of the stainless steel powder sprayed on the substrate 2.

[0051] In this embodiment, the thickness of the first coating 4 and the second coating can be controlled at 0.02-0.5mm, and during cold spraying, the precise spraying position and the minimum area of ​​the stainless steel coating can be controlled, the minimum area is 1mm 2. It can be selected according to the size of the substrate to be sprayed. If the size of the substrate is small, it should be sprayed by a precise spray method. At the same time, in order to avoid the coating being too thick and increasing the weight of the substrate, the thickness is changed in this embodiment. It is controlled between 0.02 and 0.5mm, and can be 0.1mm, 0.2mm, etc.

[0052] In addition, this embodiment also provides a hybrid spraying method, which is obtained by repeating step 1) and step 2) in sequence. Firstly, the first coating is obtained by thermal spraying, and then spraying on the surface of the first coating by cold spraying to obtain the second coating, and then spraying on the surface of the second coating by thermal spraying, and repeat step 1 in turn. ) And step 2), the surface of the multilayer composite metal layer can be obtained. By using Cu alloy, Al alloy or Zn alloy as the base for the intermediate layer, the bonding force between the layers is improved, and the outermost layer is cold sprayed with stainless steel powder to enhance the density of the outermost layer, which can effectively improve the surface quality and improve Improved corrosion resistance and so on. Of course, when mixed spraying, the same material for each layer can also be used for spraying.

[0053] The working process of this embodiment is as follows: first, the thermal spraying raw material powder, such as Cu alloy, Al alloy or Zn alloy, is heated to a molten state, and then sprayed on the surface of the substrate 2 under the action of the spray gun 1 to form the first coating 4. At this time, the surface quality of the first coating 4 is poor, not dense enough, and has poor adhesion. Then, cold spraying stainless steel powder on the first coating 4 forms a denser second coating. When the stainless steel powder particles hit the first coating 4, plastic deformation will occur on the first coating 4, and the high-speed particles will be embedded on the first coating 4 to form a denser second coating. It can also be mixed Spraying to form a surface coating with multiple layers of different alloys.