阅读说明：本技术 用于模具修复的激光熔覆合金粉末及其制备方法 (Laser cladding alloy powder for die repair and preparation method thereof ) 是由 伍林麟 赵立晓 邢志勇 于 2020-06-23 设计创作，主要内容包括：本发明实施例公开了一种用于模具修复的激光熔覆合金粉末及其制备方法。所述用于模具修复的激光熔覆合金粉末按照质量百分比由以下成分组成：铬为18％-19％、镍为3.6％-4％、钼为1.5％-1.7％、硅为1.1％-1.3％、硼0.9％-1.1％、铌为0.5％-0.55％、碳为0.15％-0.2％、锰为0.2％-0.3％、钒为0.1％-0.15％、钴为0.1％-0.15％、氮为0.06％-0.08％以及余量为铁；以上各质量百分比之和为100％。本发明实施例有效解决现有的合金粉末经过激光熔覆之后所形成的熔覆层在酸性环境下易于被腐蚀的问题。(The embodiment of the invention discloses laser cladding alloy powder for repairing a mold and a preparation method thereof. The laser cladding alloy powder for repairing the die comprises the following components in percentage by mass: 18 to 19 percent of chromium, 3.6 to 4 percent of nickel, 1.5 to 1.7 percent of molybdenum, 1.1 to 1.3 percent of silicon, 0.9 to 1.1 percent of boron, 0.5 to 0.55 percent of niobium, 0.15 to 0.2 percent of carbon, 0.2 to 0.3 percent of manganese, 0.1 to 0.15 percent of vanadium, 0.1 to 0.15 percent of cobalt, 0.06 to 0.08 percent of nitrogen and the balance of iron; the sum of the mass percentages is 100 percent. The embodiment of the invention effectively solves the problem that a cladding layer formed by laser cladding of the existing alloy powder is easy to corrode in an acid environment.)

1. The laser cladding alloy powder for repairing the die is characterized by comprising the following components in percentage by mass:

18 to 19 percent of chromium, 3.6 to 4 percent of nickel, 1.5 to 1.7 percent of molybdenum, 1.1 to 1.3 percent of silicon, 0.9 to 1.1 percent of boron, 0.5 to 0.55 percent of niobium, 0.15 to 0.2 percent of carbon, 0.2 to 0.3 percent of manganese, 0.1 to 0.15 percent of vanadium, 0.1 to 0.15 percent of cobalt, 0.06 to 0.08 percent of nitrogen and the balance of iron;

the sum of the mass percentages is 100 percent.

2. The laser cladding alloy powder for mold repair of claim 1, wherein the particle size of the alloy powder is in the range of 15-175 μ ι η.

3. The laser cladding alloy powder for die repair of claim 1, wherein a cladding layer obtained after laser cladding on a substrate using the alloy powder has the following structure:

the surface layer of the cladding layer is fine grains;

the joint of the cladding layer and the substrate is fine grains;

the interior of the cladding layer is columnar crystal.

4. The laser cladding alloy powder for mold repair of claim 1, wherein said

5. A preparation method of laser cladding alloy powder for repairing a mold is characterized by comprising the following steps:

the raw materials are obtained according to the following components in parts by mass: 17.48 to 18.61 parts of chromium, 3.6 to 4 parts of nickel, 1.5 to 1.7 parts of molybdenum, 1.1 to 1.3 parts of silicon, 0.9 to 1.1 parts of boron, 0.5 to 0.55 part of niobium, 0.15 to 0.2 part of carbon, 0.2 to 0.3 part of manganese, 0.1 to 0.15 part of vanadium, 0.1 to 0.15 part of cobalt, 0.67 to 0.89 part of nitrogen-nitrided ferrochrome and 71.05 to 73.7 parts of iron;

heating all the raw materials to a liquid state to obtain a molten liquid;

atomizing the molten liquid in a nitrogen environment to obtain the laser cladding alloy powder for repairing the die as claimed in any one of claims 1 to 4.

6. The method for preparing laser cladding alloy powder for die repair according to claim 5, wherein the step of heating all raw materials to a liquid state to obtain a melt comprises the following steps:

heating all the raw materials to liquid state, and keeping the raw materials at 1550-1600 ℃ for 2-3min to obtain the melt.

7. The method for preparing laser cladding alloy powder for die repair according to claim 5, wherein the atomizing of the melt in a nitrogen environment is performed in a closed space, and comprises:

the melt flows downwards from the upper part of the closed space with the flowing diameter of 5.0-5.5 mm;

introducing nitrogen into the closed space at the pressure of 3.0-3.5 MPa; and introducing nitrogen into the closed space to atomize the flowing melt.

8. The method for preparing laser cladding alloy powder for die repair according to claim 5, further comprising:

and screening the laser cladding alloy powder for repairing the die, wherein the screening is required to screen out the alloy powder with the particle size range of 15-175 microns.

9. The method for preparing laser cladding alloy powder for die repair according to claim 5, further comprising:

carrying out component determination on the laser cladding alloy powder for repairing the die, wherein the component determination result is as follows:

the laser cladding alloy powder for repairing the die comprises the following components in percentage by mass: 18 to 19 percent of chromium, 3.6 to 4 percent of nickel, 1.5 to 1.7 percent of molybdenum, 1.1 to 1.3 percent of silicon, 0.9 to 1.1 percent of boron, 0.5 to 0.55 percent of niobium, 0.15 to 0.2 percent of carbon, 0.2 to 0.3 percent of manganese, 0.1 to 0.15 percent of vanadium, 0.1 to 0.15 percent of cobalt, 0.06 to 0.08 percent of nitrogen, 71.47 to 73.79 percent of iron and a small amount of inevitable impurities.

Technical Field

The invention relates to the technical field of laser cladding, in particular to laser cladding alloy powder for repairing a mold, and further relates to a preparation method of the alloy powder.

Background

At present, the laser cladding technology is widely applied to the repair of metal parts, alloy powder is cladded on the position to be repaired of the metal part through the laser cladding technology, and a cladding layer is formed on the position to be repaired.

However, the cladding layer formed after laser cladding of the existing alloy powder is easily corroded in an acidic environment.

Disclosure of Invention

Therefore, the embodiment of the invention provides laser cladding alloy powder for die repair and a preparation method of the alloy powder, which effectively solve the problems in the prior art.

On one hand, the laser cladding alloy powder for repairing the die provided by the embodiment of the invention comprises the following components in percentage by mass: 18 to 19 percent of chromium, 3.6 to 4 percent of nickel, 1.5 to 1.7 percent of molybdenum, 1.1 to 1.3 percent of silicon, 0.9 to 1.1 percent of boron, 0.5 to 0.55 percent of niobium, 0.15 to 0.2 percent of carbon, 0.2 to 0.3 percent of manganese, 0.1 to 0.15 percent of vanadium, 0.1 to 0.15 percent of cobalt, 0.06 to 0.08 percent of nitrogen and the balance of iron; the sum of the mass percentages is 100 percent.

In one embodiment of the invention, the alloy powder has a particle size in the range of 15-175 μm.

In one embodiment of the present invention, a cladding layer obtained after laser cladding on a substrate using the alloy powder has the following structure: the surface layer of the cladding layer is fine grains; the joint of the cladding layer and the substrate is fine grains; the interior of the cladding layer is columnar crystal.

In one embodiment of the invention, the alloy powderFlow rate value ofBulk density value

In another aspect, an embodiment of the present invention provides a method for preparing an alloy powder according to any one of the above embodiments, including: the method comprises the following steps: the raw materials are obtained according to the following components in parts by mass: 17.48 to 18.61 parts of chromium, 3.6 to 4 parts of nickel, 1.5 to 1.7 parts of molybdenum, 1.1 to 1.3 parts of silicon, 0.9 to 1.1 parts of boron, 0.5 to 0.55 part of niobium, 0.15 to 0.2 part of carbon, 0.2 to 0.3 part of manganese, 0.1 to 0.15 part of vanadium, 0.1 to 0.15 part of cobalt, 0.67 to 0.89 part of nitrogen-nitrided ferrochrome and 71.05 to 73.7 parts of iron; heating all the raw materials to a liquid state to obtain a molten liquid; atomizing the molten liquid in a nitrogen environment to obtain the laser cladding alloy powder for repairing the die.

In an embodiment of the present invention, the heating all the raw materials to a liquid state to obtain a melt includes: heating all the raw materials to liquid state, and keeping the raw materials at 1550-1600 ℃ for 2-3min to obtain the melt.

In an embodiment of the present invention, the atomizing the melt in a nitrogen environment is performed in a closed space, and includes: the melt flows downwards from the upper part of the closed space with the flowing diameter of 5.0-5.5 mm; introducing nitrogen into the closed space at the pressure of 3.0-3.5 MPa; and introducing nitrogen into the closed space to atomize the flowing melt.

In one embodiment of the present invention, further comprising: and screening the laser cladding alloy powder for repairing the die, wherein the screening is required to screen out the alloy powder with the particle size range of 15-175 microns.

In one embodiment of the present invention, further comprising: carrying out component determination on the laser cladding alloy powder for repairing the die, wherein the component determination result is as follows: the laser cladding alloy powder for repairing the die comprises the following components in percentage by mass: 18 to 19 percent of chromium, 3.6 to 4 percent of nickel, 1.5 to 1.7 percent of molybdenum, 1.1 to 1.3 percent of silicon, 0.9 to 1.1 percent of boron, 0.5 to 0.55 percent of niobium, 0.15 to 0.2 percent of carbon, 0.2 to 0.3 percent of manganese, 0.1 to 0.15 percent of vanadium, 0.1 to 0.15 percent of cobalt, 0.06 to 0.08 percent of nitrogen, 71.47 to 73.79 percent of iron and a small amount of inevitable impurities.

In summary, the above embodiments of the present application may have the following advantages or beneficial effects: the alloy powder properly increases the contents of chromium, nickel and molybdenum, and simultaneously increases the contents of cobalt, niobium, vanadium and nitrogen, so that the alloy powder is modified, and a cladding layer obtained after laser cladding has good corrosion resistance in an acid environment, particularly a weak acid environment with the pH value of 3.1-7.0.

For example, the working environment of the injection mold is changed into a weakly acidic environment due to the release of acidic gas caused by heating of the plastic material, and after the damaged part of the injection mold is repaired by laser cladding with the alloy powder provided by the embodiment, the cladding layer generated at the damaged part of the injection mold has good corrosion resistance in the acidic environment. For another example, a shaft of a large mechanical pump may encounter an acidic environment during use, for example, when the large mechanical pump works in a coal mine, after a damaged portion of the shaft is repaired by laser cladding using the alloy powder provided in this embodiment, a cladding layer generated at the damaged portion of the shaft has good corrosion resistance under the corresponding acidic environment. This is not to be taken as an example.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic process diagram of step S3 in the method for preparing the alloy powder of the first embodiment according to the second embodiment of the present invention.

FIG. 2 is an electron microscope image of alloy powder produced by the composition ratio of embodiment one in a second example of the present invention.

FIG. 3 is an electron microscope image of alloy powder produced by the component ratios of embodiment two in a second example of the invention.

Fig. 4 is an enlarged view 100 times of the clad layer and the substrate joint in the slicing process, which is obtained by laser cladding the alloy powder prepared in the first embodiment on the substrate, slicing the clad layer and the combined part of the substrate.

Fig. 5 is a 200-fold enlarged view of the middle region of the cladding layer in the slice of fig. 4.

FIG. 6 is an enlarged view of the near-surface area of the cladding layer in the slice of FIG. 4 taken at 200 times.

FIG. 7 is an enlarged view of the area of the cladding layer adjacent to the substrate in the slice of FIG. 4 taken at 200 times.

Fig. 8 is a schematic view of a test piece including the cladding layer 10 obtained by laser cladding the test piece with the alloy powder obtained in the first embodiment.

Fig. 9 is a schematic diagram of the test piece shown in fig. 8 subjected to a neutral salt spray test.

FIG. 10 is a schematic diagram of the neutral salt spray test shown in FIG. 9 followed by the accelerated copper salt spray test.

Description of the main element symbols:

10 is molten liquid; 20 is alloy powder; 30 is a closed space; 31 is a tundish; 40 is a spray disk; 41 is a molten liquid leak hole; 42 is an air flow channel; 50 is nitrogen input equipment; 60 is nitrogen reflux equipment; the width between AB is the flow diameter of the melt 10 flowing freely downwards.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

[ first embodiment ] A method for manufacturing a semiconductor device

The first embodiment of the invention provides alloy powder, which can repair a base body, wherein the base body can be a part made of metal or alloy materials, and specifically, the alloy powder is cladded on a part to be repaired of the base body made of metal materials through a laser cladding technology, so that a cladding layer is generated on the part to be repaired of the base body, and the aim of repairing the base body is fulfilled. In addition, the cladding layer has good corrosion resistance in an acid environment, so that the service life of the substrate in the acid environment can be prolonged, and the cost of the substrate can be reduced.

Preferably, the alloy powder is used for carrying out laser cladding on a part to be repaired of the mold to repair the mold, and the mold can be an injection mold or a die-casting mold made of metal materials, and can also be other types of molds. The mold works in an acid environment, for example, the working environment of the injection mold and the die-casting mold is weakly acidic because acid gas is generated by heating the plastic inevitably in the using process, and the acid gas can be HCl, HF or even H generated by heating the plastic₂S, and the like. And the cladding layer generated on the die after the alloy powder is subjected to laser cladding has good corrosion resistance in the weak acidic environment.

Certainly, the cladding layer generated by repairing parts made of other metal materials or alloy materials by using the alloy powder by adopting a laser cladding technology has good corrosion resistance in an acid environment, particularly a weak acid environment with the pH value of 3.1-7.0.

The alloy powder comprises the following components in percentage by mass: 18 to 19 percent of chromium element, 3.6 to 4 percent of nickel element, 1.5 to 1.7 percent of molybdenum element, 1.1 to 1.3 percent of silicon element, 0.9 to 1.1 percent of boron element, 0.5 to 0.55 percent of niobium element, 0.15 to 0.2 percent of carbon element, 0.2 to 0.3 percent of manganese element, 0.1 to 0.15 percent of vanadium element, 0.1 to 0.15 percent of cobalt element, 0.06 to 0.08 percent of nitrogen element and the balance of iron element; and the sum of the mass percentages of the components is 100 percent.

Compared with the existing alloy powder, the alloy powder improves the mass percentage content of chromium element, nickel element and molybdenum element, and increases trace cobalt element, niobium element, vanadium element and nitrogen element.

Specifically, the mass percentage content of the nickel element and the molybdenum element is increased, the passivation range of the cladding layer generated by laser cladding of the alloy powder can be effectively expanded, and therefore the corrosion resistance of the cladding layer, especially the corrosion resistance of the non-oxidizing acidic medium, can be improved.

The mass percentage content of the chromium element is improved, the chromium element can absorb the carbon element in the laser cladding process to form a compound of carbon and chromium, so that the influence of the carbon element on the corrosion resistance of the cladding layer is reduced; meanwhile, the chromium element with higher mass percentage content can be beneficial to resisting the intergranular corrosion in the cladding layer; moreover, the chromium element with higher mass percentage content is beneficial to generating a cladding layer with austenitic stainless steel on the part to be repaired of the metal part to be repaired in the laser cladding process of the alloy powder.

Adding trace nitrogen element to form corresponding nitride with the metal element in the metal part to be repaired, such as nitride of iron nitride, chromium nitride and the like; the nitride has good hardness, thermal stability and dispersivity, and can improve the hardness and wear resistance of the cladding layer.

And trace niobium and vanadium are added, so that a stable carbon niobium compound and/or carbon vanadium compound can be generated with carbon elements in a metal part to be repaired in the laser cladding process, and the generation amount of the carbon chromium compound is controlled, so that the harmful effect of carbon is reduced, and the influence of the chromium elements on the corrosion resistance of the cladding layer is correspondingly improved.

And trace cobalt element is added, so that the formation of austenite can be promoted in the laser cladding process, and the formation of a cladding layer with austenitic stainless steel is promoted at the part to be repaired of the metal part to be repaired.

The alloy powder also has, for example, the following physical properties: the grain size range of the alloy powder is 15-175 μm; the alloy powder has a flow rate value of

The bulk density value of the alloy powder is

The cladding layer formed by laser cladding of the alloy powder has the following characteristics: fine grains are generated at the joint of the cladding layer and the substrate, and the grain size of the fine grains is between 0.01 and 0.02 mm; fine grains are also generated on the surface layer of the cladding layer, and the grain diameter of the fine grains is also between 0.01 and 0.02 mm; columnar crystals are generated inside the cladding layer, the width of the columnar crystals is 0.01-0.02mm, and the length of the columnar crystals is 0.05-0.15 mm.

[ second embodiment ]

A second embodiment of the present invention provides a method of producing the alloy powder according to the first embodiment, for example, including the steps of:

step S1, obtaining the following raw materials in parts by mass: 17.48 to 18.61 parts of elemental chromium, 3.6 to 4 parts of elemental nickel, 1.5 to 1.7 parts of elemental molybdenum, 1.1 to 1.3 parts of elemental silicon, 0.9 to 1.1 parts of elemental boron, 0.5 to 0.55 part of elemental niobium, 0.15 to 0.2 part of elemental carbon, 0.2 to 0.3 part of elemental manganese, 0.1 to 0.15 part of elemental vanadium, 0.1 to 0.15 part of elemental cobalt, 0.67 to 0.89 part of nitrogen chromium nitride and 71.05 to 73.7 parts of elemental iron;

step S2, heating all the raw materials obtained in the step S1 to a liquid state to obtain a molten liquid;

in step S3, the melt is atomized in a nitrogen atmosphere, so as to obtain the alloy powder according to the first embodiment.

Specifically, all the raw materials in the step S1 may be in a powder form or a block form, and are not limited herein.

In step S2, the mixture may be heated by using a medium frequency induction crucible. Specifically, all the raw materials obtained in step S1 may be sequentially added to the intermediate frequency induction crucible for heating, or all the raw materials obtained in step S1 may be uniformly mixed and then added to the intermediate frequency induction crucible for heating; in the heating process, when all the raw materials are heated to the liquid state, in order to ensure that all the raw materials are in the liquid state, the medium frequency induction crucible can be kept at 1550-.

In step S3, the melt may be atomized by using an alloy powder atomizing device. Referring to fig. 1, the atomizing apparatus has, for example, a closed space 30, and a tundish 31 for containing the melt 10 obtained in step 2 is provided at the top of the closed space 30; the upper part of the closed space 30 is connected with a nitrogen input device 50, the nitrogen input device 50 is used for introducing nitrogen into the closed space 30, the lower part of the closed space 30 is connected with a nitrogen backflow device 60, and the nitrogen backflow device 60 is used for discharging nitrogen in the closed space 30, so that the nitrogen input into the closed space 30 by the nitrogen input device 50 can flow; the spray tray 40 is arranged in the closed space 30, the spray tray 40 is positioned below the tundish 31, the spray tray 40 is provided with a melt leakage hole 41, the melt leakage hole 41 is opposite to an opening (not shown in the figure) which is arranged on the tundish 31 and used for enabling the melt 10 to freely flow downwards, the spray tray 40 is also provided with an airflow channel 42, and the airflow channel 42 is used for changing the flowing direction of the nitrogen airflow.

Further, the process of implementing step S3 by using the atomization apparatus is, for example: transferring the melt 10 obtained in the step S2 to a tundish 31; the melt 10 freely flows downwards from the opening below the tundish 31, and the flow diameter (the width between AB in FIG. 1) of the melt 10 when freely flowing downwards is preferably 5.0-5.5 mm; and the melt 10 passes through the melt leakage hole 41 on the spray plate 40; on the other hand, the nitrogen input device 50 introduces nitrogen into the closed space 30 at a pressure of 3-3.6MPa, the flow direction of the nitrogen can be changed by the flow channel 42 on the disk 40 (as shown in fig. 1), the nitrogen flow with the changed direction can blow and scatter the melt 10 flowing below the disk 40 to realize the nitrogen atomization process, the atomized melt 10 falls on the bottom of the closed space 30 through free falling to form the alloy powder 20, and the alloy powder 20 is the alloy powder described in the first embodiment; when the nitrogen gas is input into the sealed space 30 by the nitrogen gas input device 50, the nitrogen gas in the sealed space 30 is discharged by the nitrogen gas reflux device 60, thereby realizing the flow of the nitrogen gas in the sealed space 30.

The preparation method for the composite material further comprises the following steps:

step S4, screening the alloy powder obtained in the step S3, wherein the screening requirement is to screen out the alloy powder with the grain size range of 15-175 μm; for example, the alloy powder may be sieved under 80-600 mesh conditions; of course, in order to obtain the alloy powder with more uniform particle size, the alloy powder obtained in step S3 may be sieved under the condition of 120-270 mesh.

The preparation method for the composite material further comprises the following steps:

step S5, component measurement is performed on the alloy powder obtained in step S3 or the sieved alloy powder obtained in step S4, and the result of the component measurement is: the alloy powder comprises the following components in percentage by mass: 18 to 19 percent of chromium element, 3.6 to 4 percent of nickel element, 1.5 to 1.7 percent of molybdenum element, 1.1 to 1.3 percent of silicon element, 0.9 to 1.1 percent of boron element, 0.5 to 0.55 percent of niobium element, 0.15 to 0.2 percent of carbon element, 0.2 to 0.3 percent of manganese element, 0.1 to 0.15 percent of vanadium element, 0.1 to 0.15 percent of cobalt element, 0.06 to 0.08 percent of nitrogen element, 71.47 to 73.79 percent of iron element and a small amount of inevitable impurities, and the prepared alloy powder is determined to be the alloy powder in the first embodiment.

Of course, other measurements, such as the flow rate and the bulk density, may be performed on the alloy powder obtained in step S3 or on the sieved alloy powder obtained in step S4; when the measured flow rate value is not more than

Bulk density value of not less thanThe alloy powder prepared by the customization is the alloy powder described in the first embodiment.

It is worth mentioning here that: the raw material composition in step S1 may also be a non-simple metal compound or a non-metal compound, and the ratio of the chromium element, the nickel element, the molybdenum element, the silicon element, the boron element, the niobium element, the carbon element, the manganese element, the vanadium element, the cobalt element, the nitrogen element, and the iron element in the finally obtained alloy powder may be in a corresponding range.

According to different selections of the mass components of the raw materials in the step S1, the method has at least five embodiments shown in the following table:

after the five embodiments listed in the above table respectively obtain the corresponding raw materials according to the components of each raw material, the steps S2 and S3, even the steps S4 and S5, are respectively performed, and finally the alloy powders corresponding to the five embodiments are obtained, which is not described herein again.

The grain size of the alloy powder obtained in the first embodiment and other physical states of the alloy powder can be seen from an electron microscope image of the alloy powder obtained in the first embodiment, and a scanning electron microscope image as shown in fig. 2 is obtained. The grain size of the alloy powder obtained in the second embodiment and other physical states of the alloy powder can be similarly seen from an electron microscope image of the alloy powder obtained in the second embodiment, as shown in fig. 2.

Specifically, the alloy powder obtained in the first embodiment is subjected to laser cladding on a substrate, for example, an injection mold made of a metal material, to obtain a cladding layer, then the cladding layer and a part of the substrate combined with the cladding layer are sliced, and then the slice is photographed under an optical metallographic microscope to obtain the following pictures:

referring to fig. 4, an enlarged view of 100 times of the junction of the cladding layer and the substrate in the cut sheet is shown. It can be observed that: the white part on the left side is the cladding layer, and the black part connected with the cladding layer is the substrate; wherein, the part of the cladding layer close to the substrate generates fine grains, and the middle area of the cladding layer generates columnar crystals.

Referring to fig. 5, which is a 200-fold enlarged view of the middle region of the cladding layer of the slice. The columnar crystals formed in the central region of the cladding layer were observed in detail.

Referring to fig. 6, which is a 200-fold enlarged view of the near-surface area of the cladding layer of the slice. It can be observed in detail that fine grains are generated in the region of the cladding layer near the surface.

Referring to fig. 7, which is a 200-fold enlarged view of the region of the cladding layer near the substrate of the cut sheet. It can be observed in detail that fine grains are generated in the region of the cladding layer close to the substrate.

Further, carrying out laser cladding on the alloy powder obtained in the first embodiment on the surface of a test piece made of a metal material to obtain a cladding layer, then carrying out a neutral salt spray test on the cladding layer generated on the surface of the test piece for 500 hours, and grading the cladding layer on the surface of the test piece according to the requirements of national standard GB/T6461-2002; and then, on the basis of the neutral salt spray test result, carrying out a 500-hour copper accelerated salt spray test on the test piece, and grading the cladding layer on the surface of the test piece again according to the requirements of the national standard GB/T6461-2002. The test requirements of the neutral salt spray test and the copper accelerated salt spray test are as follows:

the process of performing the center salt spray test and the accelerated salt spray test on the test piece is as follows:

referring to fig. 8, the test piece has a cylindrical structure, and a cladding layer 10 is formed on the surface of the test piece by using the alloy powder obtained in the first embodiment through a laser cladding technology; wherein the thickness of the cladding layer 10 is 1.4mm, and then, the cladding layer 10 is divided into at least 4 regions (a first region 11, a second region 12, a third region 13, and a fourth region 14) and refined to different degrees, respectively, to obtain a thickness of the first region 11 of 0.3mm, a thickness of the second region 12 of 0.4mm, a thickness of the third region of 0.5mm, and a thickness of the fourth region of 0.6 mm.

Then, the test piece was subjected to a neutral salt spray test according to the above test requirements, to obtain a test result as shown in fig. 9. It can be observed that the bare matrix of the test piece is corroded seriously and rusty spots appear more; however, the surface of the cladding layer 10 of the test piece exhibited metallic luster, excellent and intact appearance, and no rust spots on the surface; and grading the surface of the cladding layer 10 according to the requirements of the national standard GB/T6461-2002 to obtain a grade Rp of 10, so that the cladding layer 10 on the surface of the test piece completely meets the requirements of a neutral salt spray test.

Finally, the test piece was subjected to a copper accelerated salt spray test on the basis of the neutral salt spray test described above, and the test results shown in fig. 10 were obtained. It can be observed that the bare matrix of the test piece is severely corroded and a large amount of rusty spots appear; however, the surface of the cladding layer 10 of the test piece exhibited metallic luster, excellent and intact appearance, and no rust spots on the surface; and grading the surface of the cladding layer 10 according to the requirements of the national standard GB/T6461-2002, wherein the obtained grading result is that Rp is 10 grade, so that the cladding layer 10 on the surface of the test piece completely meets the requirements of the copper accelerated salt spray test.

As described above, after the alloy powder according to the first embodiment prepared by the preparation method according to the second embodiment is used for repairing a substrate made of a metal material by laser cladding, a cladding layer formed on the repaired portion of the substrate has very good corrosion resistance in an acidic environment, and particularly a weakly acidic environment with a pH value of 3.1-7.0.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.