Zinc-magnesium alloy powder for thermal spraying and method for producing the same

Abstract

The application belongs to the technical field of alloy material production, and discloses a preparation method of zinc-magnesium alloy powder for thermal spraying, mainly comprising the following steps: mixing zinc raw material and magnesium raw material according to a molar ratio of 87.6:12.4, heating to 550-570 DEG C under a nitrogen environment to melt, and keeping warm for 5-10 minutes to obtain a zinc-magnesium mixed solution; transferring the zinc-magnesium mixed solution to a heat preservation crucible in a melting chamber of an atomization furnace, arranging a free-fall type nozzle at the bottom of the heat preservation crucible, extending the free-fall type nozzle into an atomization chamber of the atomization furnace, controlling the pore diameter of the free-fall type nozzle to be 2-4 mm, atomizing and powdering under a nitrogen environment by controlling the atomization pressure to be 10-10.5 bar, collecting and screening the powder after atomization and powdering to obtain zinc-magnesium alloy powder for thermal spraying; the zinc-magnesium alloy powder prepared by the above method has the advantages of high uniformity of component dispersion and uniform particle size, and when block raw materials are used, the zinc-magnesium alloy powder still has high uniformity of component dispersion and uniform particle size.

Description

Technical Field

[0001] This invention relates to the field of alloy material production technology, and in particular to a zinc-magnesium alloy powder for thermal spraying and its preparation method. Background Technology

[0002] Thermal spraying is a surface strengthening technology. It uses heat sources such as electric arcs, plasma arcs, or gas to heat metallic or non-metallic materials to a molten or semi-molten state. Under the action of a high-speed airflow, these materials are atomized into fine droplets or high-temperature particles, which are then sprayed at high speeds onto the surface of the workpiece, forming a strong coating layer. This imparts various special physicochemical properties to the workpiece surface, such as different hardness, wear resistance, corrosion resistance, heat insulation, and electrical insulation. In thermal spraying, the particle size uniformity and the dispersion uniformity of the powder raw materials have a crucial impact on the performance of the sprayed coating. Increasing the particle size uniformity of the powder raw materials improves the coating quality and thickness uniformity. Furthermore, improving the dispersion uniformity of the powder raw materials enhances the overall component dispersion uniformity within the coating, further improving the coating quality.

[0003] Chinese patent application 201911293905.1 discloses a method for preparing Fe3O4-Co3O4 powder for thermal spraying, including steps of Fe3O4 impurity removal, batching, emulsification and slurry preparation, spray drying, high-temperature sintering, and densification. This invention adds a small amount of ZIF-67 powder to the Fe3O4 powder as an improvement, uses emulsification and slurry preparation to uniformly combine the Fe3O4 powder and ZIF-67 powder, and uses gradient sintering to transform the ZIF-67 powder into a hollow dodecahedral Co3O4 structure. Compared with thermal spraying coatings formed from pure Fe3O4 powder, the thermal radiation coefficient is significantly improved. As can be seen from the specification, this method achieves uniform combination of Fe3O4 powder and ZIF-67 powder through emulsification and slurry preparation. Meanwhile, the subsequent heat treatment not only stabilizes the bond of the Fe3O4-Co3O4 finished powder particles, but also retains the characteristics of ZIF-67, such as high pore size, large specific surface area, small particle size, and high stability. Compared with pure Fe3O4 powder, the thermal radiation coefficient is significantly improved. In addition, quenching and forming can make the Fe3O4-Co3O4 powder more compact and stable, and can also control the size of the pore structure in the Fe3O4-Co3O4 powder, so as to improve the density under the premise of structural stability and further improve the thermal radiation coefficient. However, it should be noted that, on the one hand, the raw material of this scheme is powder, and the uniformity of powder after mixing is easier to control than that of block raw material. On the other hand, this scheme is designed more to improve the thermal radiation coefficient of the powder.

[0004] Chinese patent application 202110953821.7 discloses an atomizing nozzle, an atomizing powder-making system, and an atomizing powder-making method. The atomizing nozzle includes a first mixing chamber, a rotatable shearing assembly disposed within the first mixing chamber, a second mixing chamber, and a gas acceleration chamber. The gas acceleration chamber has an outer wall and a conical cavity disposed within the outer wall, the opening of which communicates with the liquid outlet of the second mixing chamber. An atomizing nozzle communicates with the tip of the conical cavity and with a third air inlet channel disposed on the outer wall of the second mixing chamber. The atomizing powder-making method described in the application is as follows: "First, a polymer melt is introduced into the system through a feeding unit, and then heating gas is supplied to the system through a gas supply unit, causing the polymer melt and heating gas to mix in the atomizing nozzle and be sprayed out at high speed." Under the impact of the velocities of the fluid and the third heating gas, the atomized liquid is ejected from the atomizing nozzle at the lower end, forming atomized droplets. The atomized droplets are cooled and solidified into fine polymer powder by the cooling unit. Then, the polymer powder is screened by the grading and screening unit to obtain polymer powders of various particle sizes. Simultaneously, this scheme controls several factors in the atomization process, such as the size of the first mixing chamber, the number of air inlets, the height-to-diameter ratio of the second mixing chamber, the diameter of the first air inlet channel, the spacing of the gas channels, the taper of the cavity, and the length-to-diameter ratio of the atomizing nozzle, to achieve the preparation of polymer powder with uniform particle size. However, it is important to note that since the purpose of this scheme is mainly to produce polymer powder, the uniformity of the dispersion of each component in the powder does not need to be considered. Furthermore, due to the different materials being produced and the different fluidity of the materials after melting, the specific atomization method and the selection of atomizing nozzles will also vary.

[0005] Chinese patent application 202110571015.3 discloses a continuous vacuum atomization preparation method for iron-based metal powder, comprising: (1) calculating the raw material ratio and weighing the raw materials according to the composition of the target steel grade; (2) smelting the raw materials in the smelting container using a vacuum atomization furnace; (3) adding a deoxidizer to the molten steel in the smelting container; (4) adding easily burnable metals from each hopper to the molten steel; (5) weighing the raw materials according to 3 / 4 to 2 / 3 of the calculated amount, and placing the next batch of raw materials in the corresponding hoppers; (6) performing atomization powder preparation, and collecting the iron-based metal powder produced in the cooling tower; (7) retaining 1 / 4 to 1 / 3 of the molten steel in the ladle, and adding the next batch of raw materials to the molten steel in sequence; (8) performing a cyclic operation according to steps (5) to (7);

[0006] As can be seen, this scheme incorporates alloying metals, deoxidizers, easily burnable metals, and other substances into the metal powder. However, an examination of the instruction manual reveals that this scheme does not give much consideration to the dispersion of these substances in the iron-based material. Furthermore, the instruction manual mentions that limiting the nozzle diameter is intended to prevent nozzle clogging. This indicates that the nozzle diameter in this scheme has no substantial impact on the powder performance.

[0007] The problem this solution aims to solve is: how to provide a method for preparing zinc-magnesium alloy powder with uniform particle size and uniform dispersion of all components for thermal spraying. Summary of the Invention

[0008] The purpose of this application is to provide a method for preparing zinc-magnesium alloy powder for thermal spraying. This method improves the particle size uniformity of zinc-magnesium alloy powder and ensures the uniform dispersion of components in zinc-magnesium alloy powder made from block raw materials by controlling nozzle orifice diameter, melting temperature and atomization pressure, thereby improving the performance of the coating after subsequent spraying.

[0009] To achieve the above objectives, this application discloses a method for preparing zinc-magnesium alloy powder for thermal spraying, mainly comprising the following steps:

[0010] A method for preparing zinc-magnesium alloy powder for thermal spraying mainly includes the following steps:

[0011] Step 1: Mix zinc and magnesium raw materials in a molar ratio of 87.6:12.4, transfer the mixture to a melting crucible in the melting chamber of an atomizing furnace, heat it to 550-570℃ under nitrogen atmosphere to melt it, and hold it at that temperature for 5-10 minutes to obtain a zinc-magnesium mixture.

[0012] Step 2: Transfer the zinc-magnesium mixture obtained in Step 1 to a heat-insulating crucible inside the atomization chamber of the atomization furnace. The bottom of the heat-insulating crucible is equipped with a free-fall nozzle that extends into the atomization chamber of the atomization furnace. The orifice diameter of the free-fall nozzle is 2-4 mm. Nitrogen gas is introduced into the melting chamber of the atomization furnace to make the pressure difference between the melting chamber and the atomization chamber of the atomization furnace reach more than 3 kPa. Driven by the pressure difference, the zinc-magnesium mixture flows out of the heat-insulating crucible and is atomized. The atomization pressure is 10-10.5 bar, and the atomizing gas is nitrogen. After atomization and powdering, the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0013] Preferably, step 1 is specifically as follows: step 1 is carried out in the melting chamber of the atomizing furnace. Before step 1, zinc raw materials and magnesium raw materials are put into the melting crucible according to the ratio. Then the melting crucible is placed in the melting chamber of the atomizing furnace, the vacuum degree in the atomizing furnace is reduced to below 20 Pa, and then nitrogen is introduced to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0014] The melting crucible is then heated to 550–570°C within 30 minutes and held at that temperature for 5–10 minutes to obtain a zinc-magnesium mixture.

[0015] Preferably, step 2 is specifically carried out in the atomization chamber of the atomization furnace. Before step 1, the heat-insulating crucible is placed in the melting chamber of the atomization furnace. After step 1 is completed, the zinc-magnesium mixture is transferred to the heat-insulating crucible. Then, nitrogen gas is introduced into the melting chamber of the atomization furnace to make the pressure difference between the melting chamber and the atomization chamber of the atomization furnace reach more than 3 kPa. Driven by the pressure difference, the zinc-magnesium mixture flows out of the heat-insulating crucible and flows through the nozzle into the atomization chamber of the atomization furnace and is atomized. After atomization and powdering, the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0016] Preferably, the zinc raw material has a purity of 4N and is a zinc block with dimensions of 28mm × 25mm × 28mm;

[0017] The magnesium raw material is a magnesium block with a purity of 4N and a size of 50mm×15mm×15mm.

[0018] Preferably, in step 1, the device for heating the melting crucible is a medium-frequency induction furnace, which is located inside the melting chamber of the atomizing furnace.

[0019] Preferably, the smelting crucible is an alumina crucible, and the heat-preserving crucible is a graphite crucible.

[0020] In addition, a zinc-magnesium alloy powder for thermal spraying is disclosed, which is prepared by the above-described method for preparing zinc-magnesium alloy powder for thermal spraying.

[0021] Preferably, the median particle size of the zinc-magnesium alloy powder used for thermal spraying is 50–70 micrometers.

[0022] Preferably, the difference in Mg element composition among the upper, middle, and lower layers of the zinc-magnesium alloy powder used for thermal spraying is less than 0.3 at%.

[0023] The beneficial effects of this application are as follows: The method for preparing zinc-magnesium alloy powder for thermal spraying provided by this application improves the particle size uniformity of zinc-magnesium alloy powder and the component dispersion uniformity of zinc-magnesium alloy powder made from block raw materials by controlling the nozzle orifice diameter, melting temperature and atomization pressure, thereby improving the coating performance after subsequent spraying. Moreover, this method is particularly suitable for the preparation of zinc-magnesium alloy powder. At the same time, the preparation process of this scheme has low requirements for raw materials. Even when the raw materials are in block form, it is still possible to prepare zinc-magnesium alloy powder with uniform particle size and uniform dispersion of each component. Detailed Implementation

[0024] The present invention will now be clearly and completely described in conjunction with embodiments thereof. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0025] It should be noted that the zinc raw material in Examples 1-5 is a zinc block with a purity of 4N and a size of 28mm×25mm×28mm;

[0026] The magnesium raw material is a magnesium block with a purity of 4N and a size of 50mm×15mm×15mm.

[0027] Example 1

[0028] Step 1: Select an alumina crucible as the melting crucible and a graphite crucible as the heat preservation crucible. Take zinc and magnesium raw materials from the melting crucible at a molar ratio of 87.6:12.4 and put them into the melting crucible. Place the melting crucible and the heat preservation crucible in the melting chamber of the atomizing furnace. Then reduce the vacuum degree in the atomizing furnace to below 20 Pa and then introduce nitrogen gas to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0029] The melting crucible was then heated to 560°C within 30 minutes and held at that temperature for 8 minutes to obtain a zinc-magnesium mixture.

[0030] Step 2: After Step 1 is completed, the zinc-magnesium mixture is transferred to an insulated crucible, and nitrogen gas is continuously introduced to make the pressure difference between the melting chamber and the atomization chamber of the atomizing furnace reach more than 3 kPa. The atomization pressure is adjusted to 10.5 bar, and the atomizing gas is nitrogen. The zinc-magnesium mixture falls through the free-fall nozzle extending from the bottom of the insulated crucible into the atomization chamber of the atomizing furnace and is atomized into powder. Then the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0031] The orifice diameter of the free-fall nozzle is 2mm.

[0032] Example 2

[0033] Step 1: Select an alumina crucible as the melting crucible and a graphite crucible as the heat preservation crucible. Take zinc and magnesium raw materials from the melting crucible at a molar ratio of 87.6:12.4 and put them into the melting crucible. Place the melting crucible and the heat preservation crucible in the melting chamber of the atomizing furnace. Then reduce the vacuum degree in the atomizing furnace to below 20 Pa and then introduce nitrogen gas to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0034] The melting crucible was then heated to 570°C within 30 minutes and held at that temperature for 5 minutes to obtain a zinc-magnesium mixture.

[0035] Step 2: After Step 1 is completed, the zinc-magnesium mixture is transferred to an insulated crucible, and nitrogen gas is continuously introduced to make the pressure difference between the melting chamber and the atomization chamber of the atomizing furnace reach more than 3 kPa. The atomization pressure is adjusted to 10.5 bar, and the atomizing gas is nitrogen. The zinc-magnesium mixture falls through the free-fall nozzle extending from the bottom of the insulated crucible into the atomization chamber of the atomizing furnace and is atomized into powder. Then the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0036] The orifice diameter of the free-fall nozzle is 3mm.

[0037] Example 3

[0038] Step 1: Select an alumina crucible as the melting crucible and a graphite crucible as the heat preservation crucible. Take zinc and magnesium raw materials from the melting crucible at a molar ratio of 87.6:12.4 and put them into the melting crucible. Place the melting crucible and the heat preservation crucible in the melting chamber of the atomizing furnace. Then reduce the vacuum degree in the atomizing furnace to below 20 Pa and then introduce nitrogen gas to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0039] The melting crucible was then heated to 550°C within 30 minutes and held at that temperature for 10 minutes to obtain a zinc-magnesium mixture.

[0040] Step 2: After Step 1 is completed, the zinc-magnesium mixture is transferred to an insulated crucible, and nitrogen gas is continuously introduced to make the pressure difference between the melting chamber and the atomization chamber of the atomizing furnace reach more than 3 kPa. The atomization pressure is adjusted to 10.5 bar, and the atomizing gas is nitrogen. The zinc-magnesium mixture falls through the free-fall nozzle extending from the bottom of the insulated crucible into the atomization chamber of the atomizing furnace and is atomized into powder. Then the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0041] The orifice diameter of the free-fall nozzle is 4mm.

[0042] Example 4

[0043] Step 1: Select an alumina crucible as the melting crucible and a graphite crucible as the heat preservation crucible. Take zinc and magnesium raw materials from the melting crucible at a molar ratio of 87.6:12.4 and put them into the melting crucible. Place the melting crucible and the heat preservation crucible in the melting chamber of the atomizing furnace. Then reduce the vacuum degree in the atomizing furnace to below 20 Pa and then introduce nitrogen gas to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0044] The melting crucible was then heated to 550°C within 30 minutes and held at that temperature for 10 minutes to obtain a zinc-magnesium mixture.

[0045] Step 2: After Step 1 is completed, the zinc-magnesium mixture is transferred to an insulated crucible. Nitrogen gas is continuously introduced to make the pressure difference between the melting chamber and the atomization chamber of the atomizing furnace reach more than 3 kPa. The atomization pressure is adjusted to 10 bar, and the atomizing gas is nitrogen. The zinc-magnesium mixture falls through the free-fall nozzle extending from the bottom of the insulated crucible into the atomization chamber of the atomizing furnace, and is atomized into powder. The powder is then collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0046] The orifice diameter of the free-fall nozzle is 3mm.

[0047] Example 5

[0048] Step 1: Select an alumina crucible as the melting crucible and a graphite crucible as the heat preservation crucible. Take zinc and magnesium raw materials from the melting crucible at a molar ratio of 87.6:12.4 and put them into the melting crucible. Place the melting crucible and the heat preservation crucible in the melting chamber of the atomizing furnace. Then reduce the vacuum degree in the atomizing furnace to below 20 Pa and then introduce nitrogen gas to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa.

[0049] The melting crucible was then heated to 560°C within 30 minutes and held at that temperature for 8 minutes to obtain a zinc-magnesium mixture.

[0050] Step 2: After Step 1 is completed, the zinc-magnesium mixture is transferred to an insulated crucible, and nitrogen gas is continuously introduced to make the pressure difference between the melting chamber and the atomization chamber of the atomizing furnace reach more than 3 kPa. The atomization pressure is adjusted to 10.3 bar, and the atomizing gas is nitrogen. The zinc-magnesium mixture falls through the free-fall nozzle extending from the bottom of the insulated crucible into the atomization chamber of the atomizing furnace and is atomized into powder. Then the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

[0051] The orifice diameter of the free-fall nozzle is 3mm.

[0052] Example 6

[0053] The method is basically the same as in Example 1, except that the zinc raw material is zinc particles with a purity of 4N and a particle size of 5mm; and the magnesium raw material is magnesium particles with a purity of 4N and a particle size of 5mm.

[0054] Comparative Example 1

[0055] It is basically the same as Example 1, except that the orifice diameter of the free-fall nozzle is 1 mm.

[0056] Comparative Example 2

[0057] It is basically the same as Example 1, except that the orifice diameter of the free-fall nozzle is 5mm.

[0058] Comparative Example 3

[0059] It is basically the same as Example 1, except that the atomization pressure is 9 bar.

[0060] Comparative Example 4

[0061] It is basically the same as Example 1, except that the atomization pressure is 12 bar.

[0062] Comparative Example 5

[0063] It is basically the same as Example 1, except that in step 1, the temperature of the melting crucible is heated to 500°C.

[0064] Comparative Example 6

[0065] It is basically the same as Example 1, except that in step 1, the temperature of the melting crucible is heated to 600°C.

[0066] Comparative Example 7

[0067] It is basically the same as Example 1, except that in step 1, the holding time of the melting crucible is 20 minutes.

[0068] Comparative Example 8

[0069] It is basically the same as Example 1, except that in step 1, the holding time of the melting crucible is 2 minutes.

[0070] Performance testing:

[0071] Component distribution uniformity test: The Mg content in the zinc-magnesium alloy powder used for thermal spraying was tested using the internal standard method. The results are shown in Table 1.

[0072] Table 1

[0073]

[0074]

[0075] Results analysis:

[0076] As can be seen from Examples 1-6, when the materials are fed at a certain molar ratio, the magnesium content in the atomized zinc-magnesium alloy powder remains stable, and the magnesium composition has good uniformity, with the difference between the components in the upper, middle, and lower layers being less than 0.3 at%. Meanwhile, observations of Examples 1-5 and Example 6 show that the uniformity of component dispersion in zinc-magnesium alloy powder prepared from block raw materials is not significantly different from that in zinc-magnesium alloy powder prepared from granular raw materials.

[0077] However, when the holding time and heating temperature of the melting crucible were changed, the difference in composition between the upper, middle and lower layers increased significantly, and the uniformity of the composition decreased.

[0078] Particle size uniformity test: The polydispersity index (PDI) and median particle size (D50) of the alloy powder were measured using a Malvern particle size analyzer. The test results are shown in Table 2.

[0079] Table 2

[0080]

[0081]

[0082] Results analysis:

[0083] As can be seen from Examples 1-6, the polydispersity coefficient of alloy powder prepared using block raw materials is not significantly different from that of alloy powder prepared using granular raw materials. Furthermore, when the temperature of the melting crucible is controlled at 560°C and held for 8 minutes, and the atomization pressure is 10.3 bar with a nozzle diameter of 3 mm, the polydispersity coefficient of the alloy powder prepared is slightly smaller than that of the alloy powder prepared using granular raw materials, and its uniformity is slightly superior.

[0084] As can be seen from Example 1 and Comparative Examples 1-8, when any of the following factors are changed: the temperature of the melting crucible, the holding time of the melting crucible, the atomization pressure, and the nozzle orifice diameter, the uniformity of the alloy powder will decrease to a certain extent.

[0085] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing zinc-magnesium alloy powder for thermal spraying, characterized in that, The main steps include: Step 1: Mix zinc and magnesium raw materials in a molar ratio of 87.6:12.4, transfer the mixture to a melting crucible in the melting chamber of an atomizing furnace, heat it to 550-570℃ under nitrogen atmosphere to melt it, and hold it at that temperature for 5-10 minutes to obtain a zinc-magnesium mixture. Step 2: Transfer the zinc-magnesium mixture obtained in Step 1 to a heat-insulating crucible inside the atomization chamber of the atomization furnace. The bottom of the heat-insulating crucible is equipped with a free-fall nozzle that extends into the atomization chamber of the atomization furnace. The orifice diameter of the free-fall nozzle is 2-4 mm. Nitrogen gas is introduced into the melting chamber of the atomization furnace to make the pressure difference between the melting chamber and the atomization chamber of the atomization furnace reach more than 3 kPa. Driven by the pressure difference, the zinc-magnesium mixture flows out of the heat-insulating crucible and is atomized. The atomization pressure is 10.5 bar, and the atomizing gas is nitrogen. After atomization and powdering, the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

2. The method for preparing zinc-magnesium alloy powder for thermal spraying according to claim 1, characterized in that, Step 1 is specifically carried out in the melting chamber of the atomizing furnace. Before step 1, zinc raw materials and magnesium raw materials are put into the melting crucible according to the ratio. Then the melting crucible is placed in the melting chamber of the atomizing furnace, the vacuum degree in the atomizing furnace is reduced to below 20 Pa, and then nitrogen is introduced to raise the pressure in the melting chamber of the atomizing furnace to 3 kPa. The melting crucible is then heated to 550–570°C within 30 minutes and held at that temperature for 5–10 minutes to obtain a zinc-magnesium mixture.

3. The method for preparing zinc-magnesium alloy powder for thermal spraying according to any one of claims 1-2, characterized in that, Step 2 is specifically carried out in the atomization chamber of the atomization furnace. Before step 1, the heat-insulating crucible is placed in the melting chamber of the atomization furnace. After step 1 is completed, the zinc-magnesium mixture is transferred to the heat-insulating crucible. Then, nitrogen gas is introduced into the melting chamber of the atomization furnace to make the pressure difference between the melting chamber and the atomization chamber of the atomization furnace reach more than 3 kPa. Driven by the pressure difference, the zinc-magnesium mixture flows out of the heat-insulating crucible and flows into the atomization chamber of the atomization furnace through the free-fall nozzle and is atomized. After atomization and powdering, the powder is collected and sieved to obtain zinc-magnesium alloy powder for thermal spraying.

4. The method for preparing zinc-magnesium alloy powder for thermal spraying according to claim 1, characterized in that, The zinc raw material has a purity of 4N and is a zinc block with dimensions of 28mm × 25mm × 28mm; The magnesium raw material is a magnesium block with a purity of 4N and a size of 50mm×15mm×15mm.

5. The method for preparing zinc-magnesium alloy powder for thermal spraying according to claim 2, characterized in that, In step 1, the device for heating and melting the crucible is a medium-frequency induction furnace, which is located in the melting chamber of the atomizing furnace.

6. The method for preparing zinc-magnesium alloy powder for thermal spraying according to claim 1, characterized in that, The smelting crucible is an alumina crucible, and the heat-insulating crucible is a graphite crucible.

7. A zinc-magnesium alloy powder for thermal spraying, characterized in that, The zinc-magnesium alloy powder for thermal spraying is prepared using any one of the methods described in claims 1-6.

8. The zinc-magnesium alloy powder for thermal spraying according to claim 7, characterized in that, The median particle size of the zinc-magnesium alloy powder used for thermal spraying is 50–70 micrometers.

9. The zinc-magnesium alloy powder for thermal spraying according to claim 7, characterized in that, The difference in Mg element composition between the upper, middle, and lower layers of the zinc-magnesium alloy powder used for thermal spraying is less than 0.3 at.

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