Corrosion-resistant coating for gas compressor blade of gas turbine and preparation method of corrosion-resistant coating

Abstract

The invention discloses a corrosion-resistant coating for a gas turbine compressor blade and a preparation method of the corrosion-resistant coating, and belongs to the technical field of coatings. Rare earth elements are added into a traditional inorganic salt aluminum coating, and the corrosion resistance and oxidation resistance of the inorganic salt aluminum coating are improved. A corrosion product of the prepared Zn-Al-Mg-rare earth alloy coating is extremely compact, a corrosion channel is blocked, the self-sealing effect of the coating is improved, and the corrosion resistance of the coating is greatly improved; and meanwhile, the Zn-Al-Mg-rare earth alloy coating obtained through electric arc spraying is high in density and good in comprehensive mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a corrosion-resistant coating for gas turbine compressor blades and a preparation method thereof. Background Art

[0002] The compressor is one of the most important parts in both aircraft engines and industrial gas turbines. A large amount of stainless steel is used in the manufacturing process of compressor blades. During use, the blades of the last few stages have to withstand the impact of high-pressure and high-speed air, erosion by corrosive media, and high-temperature oxidation and corrosion, which are prone to corrosion or erosion damage. Problems such as compressor blade corrosion and high-temperature oxidation caused by dust, salt and other factors in the atmosphere have always attracted much attention. At present, the domestic corrosion and oxidation protection of compressor blades mainly adopts a composite coating of low-temperature aluminizing and inorganic salts, which has strong corrosion resistance, but the aluminizing layer has the disadvantages of thin thickness and loose texture, which will affect its long-term corrosion resistance, and the coating preparation process is complicated and the cost is high. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above and / or existing problems in the prior art, the present invention is proposed

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a corrosion-resistant coating for a gas turbine compressor blade.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions, including:

[0007] The inorganic salt aluminum coating is sprayed on the surface of the cleaned blade multiple times by air spraying, dried and solidified to form an inorganic salt aluminum coating; after the inorganic salt aluminum coating is shot peened and conductively treated, an arc spraying technology is used to prepare a Zn-Al-Mg-rare earth alloy coating on the surface of the inorganic salt aluminum coating;

[0008] The Zn-Al-Mg-rare earth alloy coating includes 20-30wt.% Al, 2-8wt.% Mg, 1-3wt.% rare earth elements, and the remaining components are Zn. The rare earth elements include one or more of Re, Ce, and La elements.

[0009] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blade of the present invention, the inorganic salt aluminum coating is prepared with water-soluble phosphate and chromate as binders and rare earth aluminum alloy powder as the main filler, including:

[0010] The mass fraction of H is 50-60%. 3 PO 4 After the solution is heated to 80-90°C, MgO powder is slowly added in batches under constant stirring until it is completely dissolved, and the temperature is raised to 120-150°C for reaction for 0.5-1.5h. After the reaction is completed, it is cooled to room temperature to form Mg(H 2 PO 4 ) 2 Solution;

[0011] Take MgO powder and slowly add it into CrO with a concentration of 150-350g / L. 3 Reaction in aqueous solution to form MgCrO 4 Solution;

[0012] Mg(H 2 PO 4 ) 2 Solution, MgCrO 4 The solution is mixed evenly, and then silica sol is added and stirred evenly to obtain a binder, and finally rare earth aluminum alloy powder is added and ultrasonically dispersed and then filtered to obtain an inorganic salt aluminum coating;

[0013] Among them, the H 3 PO 4 The mass ratio of CrO to MgO is 2.5-3.5:0.8-1.4; 3 The mass ratio of magnesium to MgO is 2.2-2.8:0.5-1.0.

[0014] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blades of the present invention, the particle size of the rare earth aluminum alloy powder is less than 5 μm, including 1.00-10.00% Ce, 0.10-0.50% Y, 0.10-2.50% Zr, and the rest is Al.

[0015] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blade of the present invention, wherein: the silica sol and Mg(H 2 PO 4 ) 2 MgCrO 4 The volume ratio of the mixed solution is 0.3-0.8:1-1.5; the mass ratio of the rare earth aluminum alloy powder and the binder is 0.5-1.2:1.5-2.2.

[0016] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blades according to the present invention, the air spraying is performed by drying in the air for 0.5 to 1 hour, then transferring to 70 to 90°C and heating for 0.5 to 1 hour, and then curing at 200 to 350°C for 0.5 to 3.5 hours.

[0017] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blade of the present invention, the cleaning treatment is to use a degreasing and rust removing agent to remove oil and rust from the blade surface, and then ultrasonically clean it for 0.5 to 1.5 hours; then use sand with a mesh size greater than 150 to perform wet sand blowing, the pressure of the compressed air used is 0.2 to 0.7 MPa, and then ultrasonically clean it for 0.5 to 1.5 hours, and finally blow dry;

[0018] The cleaning solution includes one or more of distilled water, anhydrous ethanol or acetone.

[0019] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blades of the present invention, the shot peening uses a mixture of 20-30 mesh glass shots and corundum sand, the blasting pressure is 45-60N, and after the treatment, the resistance of any area 30mm apart on the coating surface is less than 15Ω.

[0020] As a preferred embodiment of the method for preparing the corrosion-resistant coating of the gas turbine compressor blades according to the present invention, the arc spraying has a current of 100 to 150A, a voltage of 30 to 40V, a spraying distance of 120 to 200mm, and a gas pressure of 0.5 to 0.8MPa.

[0021] As a preferred embodiment of the method for preparing the corrosion-resistant coating for gas turbine compressor blades of the present invention, the thickness of the inorganic salt aluminum coating is 50 to 100 μm; the thickness of the Zn-Al-Mg-rare earth alloy coating is 100 to 200 μm.

[0022] Another object of the present invention is to overcome the deficiencies in the prior art and provide a corrosion-resistant coating for gas turbine compressor blades.

[0023] Beneficial effects of the present invention:

[0024] (1) The present invention adds rare earth elements to the traditional inorganic salt aluminum coating, thereby improving the corrosion resistance and oxidation resistance of the inorganic salt aluminum coating.

[0025] (2) The corrosion products of the Zn-Al-Mg-rare earth alloy coating prepared by the present invention are extremely dense, which blocks the corrosion channels, improves the self-sealing effect of the coating, and greatly improves the anti-corrosion performance of the coating; at the same time, the arc sprayed Zn-Al-Mg-rare earth alloy coating has high density and good comprehensive mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0027] Figure 1 The present invention is a schematic structural diagram of the corrosion-resistant coating for gas turbine compressor blades prepared in the present invention.

[0028] Figure 2 This is the appearance of the inorganic salt aluminum coating prepared in Example 1 after 1000 hours of salt spray test.

[0029] Figure 3 This is the appearance of the inorganic salt aluminum coating prepared in Example 1 after 3500 hours of salt spray test.

[0030] Figure 4 This is the appearance of the inorganic salt aluminum coating prepared in Example 1 after 100 salt spray-heat exposure cycles.

[0031] Figure 5 This is the microscopic morphology of the Zn-Al-Mg-rare earth alloy coating prepared in Example 1 after 500h salt spray test.

[0032] Figure 6 This is the appearance of the traditional inorganic salt aluminum coating prepared in this comparative example after 1000 hours of salt spray test.

[0033] Figure 7 This is the appearance of the traditional inorganic salt aluminum coating prepared in this comparative example after 100 salt spray-heat exposure cycles. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0037] The raw materials used in the present invention are all commercially available unless otherwise specified.

[0038] Phosphoric acid, MgO, CrO 3 , silica sol were analytically pure

[0039] The performance of the material prepared in the embodiment of the present invention was tested as follows:

[0040] 1) Adhesion test:

[0041] According to the ASTM C633 standard, the prepared gas turbine compressor corrosion-resistant coating sample proposed by the present invention is placed on a tensile machine for tensile testing.

[0042] 2) Salt spray test and salt spray-heat exposure test are used to test the corrosion resistance and oxidation resistance of the coating:

[0043] ① Carry out salt spray test according to ASTM B117 standard requirements, seal the cut edges of the specimens for protection, use a knife to scratch "×" on the surface of the specimens, and then put them into the salt spray test chamber. Take out the specimens after a certain period of time and take pictures to observe whether there is rust on the surface of the specimens, especially at the "×" mark. If rust occurs, it means that the specimen has been corroded and damaged.

[0044] ② Carry out a 500h salt spray test according to ASTM B117 standard. The test conditions are: the temperature in the salt spray chamber is controlled at 35±2℃, a neutral NaCl solution with a mass fraction of 5±0.5% is used for continuous salt spray, the pH range is 6.5-7.2, and the salt spray time is 500h. After the salt spray test, the sample is rinsed with deionized water, dried, and the surface morphology is observed to study the corrosion resistance of the coating.

[0045] ③ Salt spray-heat exposure test is carried out in accordance with ASTM B117 standard. First, a 1000h, 5% salt spray test is carried out, and then the test is kept in a heating furnace at 450±10℃ for 6 hours. This is one cycle, and a total of 100 cycles are carried out. After the test, observe the surface of the sample, especially the "×" mark to see if there is rust and the extension of the rust mark.

[0046] Example 1

[0047] This embodiment provides a method for preparing a corrosion-resistant coating. The coating structure is as shown in Figure 1 , specifically:

[0048] (1) The blade surface is degreased and rusted using a commercial degreasing and rust removing agent, and then ultrasonically cleaned for 1 hour using distilled water, anhydrous ethanol or acetone as the cleaning solution; then wet sandblasting is performed using sand with a mesh size greater than 150, and the compressed air pressure used is 0.5 MPa, followed by ultrasonic cleaning for 1 hour using anhydrous ethanol or acetone as the cleaning solution, and finally blown dry for use.

[0049] (2) 58% H 3 PO 4 The solution was heated to 85°C and the mass ratio of H 3 PO 4 MgO = 3.0:1.2 Take MgO powder and add it slowly and in batches into H 3 PO 4 The solution was completely dissolved, the temperature was raised to 130°C, the reaction was continued for 1 hour, and after the reaction was completed, the solution was cooled to room temperature to form Mg(H 2 PO 4 ) 2 solution, pH between 3 and 3.5; then, according to the mass ratio of CrO 3 :MgO=2.5:0.8 Take MgO powder and slowly add it into CrO with a concentration of 300g / L 3 Reaction in aqueous solution to form MgCrO 4 solution; then Mg(H 2 PO 4 ) 2 Solution, MgCrO 4 The solution is mixed evenly, and then silica sol is added and stirred evenly to obtain a binder. Finally, rare earth aluminum alloy powder (the particle size of rare earth aluminum alloy powder is less than 5μm, Ce is 5.00%, Y is 0.30%, Zr is 2.00%, and the rest is Al) is added according to the mass ratio of rare earth aluminum alloy powder: binder = 0.8:1.8, and then filtered after ultrasonic dispersion to obtain a coating. Silica sol in the coating: Mg(H 2 PO 4 ) 2 MgCrO 4 The volume ratio of the mixed solution = 0.6:1.2. The compressor blade surface was sprayed multiple times by air spraying, dried in air for 1 hour, heated at 80°C for 1 hour, and then cured at 320°C for 3 hours to form an inorganic salt aluminum coating with a coating thickness of 80 μm.

[0050] (3) The coating surface is shot peened with a mixture of 20-30 mesh glass beads and corundum sand at a blasting pressure of 50N. After treatment, the resistance of the coating surface measured by a multimeter at any distance of 30mm is less than 15Ω.

[0051] (4) Using arc spraying technology, Zn-Al-Mg-rare earth alloy coating is prepared on the surface of inorganic salt aluminum coating. Using arc spraying method, Zn-Al-Mg-rare earth powder core wire is used to prepare Zn-Al-Mg-rare earth alloy coating. The arc spraying process parameters are: current 120A, voltage 35V, spraying distance 170mm, gas pressure 0.6MPa. The composition of Zn-Al-Mg-rare earth alloy coating: Al is 25%, Mg is 4%, rare earth content is 6% (Re, Ce, La each 2%), and the rest is Zn. The thickness of Zn-Al-Mg-rare earth alloy coating is 150μm.

[0052] Figure 2 This is the appearance picture of the inorganic salt aluminum coating prepared in this example after 1000 hours of salt spray test.

[0053] Figure 3 This is the appearance picture of the inorganic salt aluminum coating prepared in this embodiment after 3500 hours of salt spray test.

[0054] Figure 4 This is the appearance of the inorganic salt aluminum coating prepared in this example after 100 salt spray-heat exposure cycles.

[0055] Figure 5 The surface microscopic morphology of the Zn-Al-Mg-rare earth alloy coating prepared in this embodiment after 500h salt spray test is shown. It can be seen that after 500h salt spray test, the surface of the Zn-Al-Mg-rare earth alloy coating is covered with a large number of white cellular corrosion products, and the enlarged micro-area observation shows that the corrosion products are tightly interlocked. This very dense layer of white corrosion products can effectively close the pores in the coating and fill the gaps, so that the entire coating maintains integrity, and further cuts off the penetration of the corrosive medium into the underlying inorganic salt aluminum coating and further the matrix alloy, thereby improving the overall corrosion resistance of the coating.

[0056] Example 2

[0057] The difference between this embodiment and embodiment 1 is that the rare earth element content of the rare earth aluminum alloy powder is adjusted to 2.00% Ce, 0.20% Y, and 0.80% Zr, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0058] Example 3

[0059] The difference between this embodiment and Embodiment 1 is that the composition of the Zn-Al-Mg-rare earth alloy coating is adjusted to 20% Al, 6% Mg, 2% rare earth content (1% each of Re, Ce, and La elements), and the remaining components are Zn. The rest of the preparation process is the same as that of Embodiment 1 to obtain a corrosion-resistant coating.

[0060] Comparative Example 1

[0061] This comparative example is a traditional inorganic salt aluminum coating, which is different from Example 1 in that the rare earth aluminum alloy powder is adjusted to aluminum alloy powder, specifically:

[0062] 58% H 3 PO 4 The solution was heated to 85°C and the mass ratio of H 3 PO 4 MgO = 3.0:1.2 Take MgO powder and add it slowly and in batches into H 3 PO 4 The solution was completely dissolved, the temperature was raised to 130°C, the reaction was continued for about 1 hour, and after the reaction was completed, the solution was cooled to room temperature to form Mg(H 2 PO 4 ) 2 solution, pH between 3 and 3.5; then, according to the mass ratio of CrO 3 :MgO=2.5:0.8 Take MgO powder and slowly add it into CrO with a concentration of 300g / L 3 Reaction in aqueous solution to form MgCrO 4 solution; then Mg(H 2 PO 4 ) 2 Solution, MgCrO 4 The solution is mixed evenly, and then silica sol is added and stirred evenly to obtain the binder. Finally, aluminum alloy powder is added according to the mass ratio of aluminum alloy powder: binder = 0.8:1.8, and the coating is obtained after ultrasonic dispersion and filtration. Silica sol in the coating: Mg(H 2 PO 4 ) 2 MgCrO 4 The volume ratio of the mixed solution is 0.6:1.2; the mass ratio of aluminum alloy powder: binder is 0.8:1.8. The compressor blade surface is sprayed multiple times by air spraying, dried in air for 1 hour, heated at 80°C for 1 hour, and then cured at 320°C for 3 hours to form an inorganic salt aluminum coating with a coating thickness of 80μm.

[0063] Figure 6 This is the appearance of the traditional inorganic salt aluminum coating prepared in this comparative example after 1000 hours of salt spray test.

[0064] Figure 7 This is the appearance of the traditional inorganic salt aluminum coating prepared in this comparative example after 100 salt spray-heat exposure cycles.

[0065] according to Figure 2 , 35. It can be seen from the comparison that the conventional inorganic salt aluminum coating sample rusted after 1000 hours of salt spray corrosion, while the inorganic salt aluminum coating sample with rare earth added proposed in the present invention still had no obvious rust on the sample surface after 3500 hours, and only a small amount of white corrosion products were formed at the "×" mark. The test results show that the inorganic salt aluminum coating with rare earth added proposed in the present invention has good salt spray corrosion resistance.

[0066] from Figure 4 and Figure 6 By comparison, it can be seen that after 100 salt spray-heat exposure cycles, the inorganic salt aluminum coating sample with added rare earth proposed in the present invention did not show obvious rust on the surface, only a small amount of rust spots appeared at the "×" mark, and did not expand outward. Therefore, it can be explained that the inorganic salt aluminum coating with added rare earth proposed in the present invention has good resistance to salt spray-heat exposure cycles.

[0067] The performance of the material prepared in the above embodiment was tested, and the comparison results with those in Example 1 are shown in Table 1.

[0068] Table 1

[0069] Breaking load / N Binding strength / MPa Salt spray resistance time Example 1 18395 37.5 ＞6000h Example 2 17904 36.5 5000h Example 3 17910 35.9 4500h

[0070] It can be seen from the above table that adjusting the rare earth content has a significant effect on the coating performance. This is because the rare earth elements can refine the coating particle structure, improve the density and uniformity of the coating structure, and make the coating have a better self-sealing effect and excellent corrosion resistance. According to the results in the above table, the rare earth elements and their contents of the rare earth aluminum alloy powder in the inorganic salt aluminum coating of the present invention are 5% Ce, 0.3% Y, and 2% Zr, respectively. When the rare earth element content of the Zn-Al-Mg-rare earth alloy coating is 6%, the best technical effect can be obtained.

[0071] Example 4

[0072] The difference between this embodiment and embodiment 1 is that the drying time of the air spraying method of the inorganic salt aluminum coating is adjusted to 0.5h, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0073] Example 5

[0074] The difference between this embodiment and embodiment 1 is that the air drying time of the inorganic salt aluminum coating air spraying method is adjusted to 1.2 hours, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0075] The performance of the material prepared in the above embodiment was tested, and the comparison results with those in Example 1 are shown in Table 2.

[0076] Table 2

[0077] Breaking load / N Binding strength / MPa Salt spray-heat exposure cycle Example 1 18395 37.5 1125 times Example 4 17463 35.6 812 times Example 5 17806 36.3 853 times

[0078] It can be seen from the above table that adjusting the drying time in the air has a significant effect on the coating adhesion, which in turn affects the coating's resistance to salt spray-heat exposure. This is because a longer drying time helps the coating to bond with the substrate, while providing a better coating structure for subsequent high-temperature heating and curing. According to the results in the above table, the inorganic salt aluminum coating air spraying method of the present invention can achieve the best technical effect when the drying time in the air is 1h.

[0079] Example 6

[0080] The difference between this embodiment and embodiment 1 is that the curing time of the inorganic salt aluminum coating air spraying method is adjusted to 1 hour, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0081] Example 7

[0082] The difference between this embodiment and embodiment 1 is that the curing temperature of the inorganic salt aluminum coating air spraying method is adjusted to 200°C, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0083] The performance of the material prepared in the above embodiment was tested, and the comparison results with those in Example 1 are shown in Table 3.

[0084] Table 3

[0085] Breaking load / N Binding strength / MPa Example 1 18395 37.5 Example 8 17071 34.8 Example 9 17512 35.7

[0086] It can be seen from the above table that adjusting the drying and curing temperature and time of the air spray method of the inorganic salt aluminum coating has a significant effect on the coating adhesion performance. According to the results in the above table, the best technical effect can be obtained when the drying and curing temperature in the present invention is 320°C and the curing time is 3h.

[0087] Example 8

[0088] The difference between this embodiment and embodiment 1 is that the arc spraying process parameters of the Zn-Al-Mg-rare earth alloy coating are adjusted to have a current of 110A and a voltage of 30V, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0089] Example 9

[0090] The difference between this embodiment and embodiment 1 is that the arc spraying process parameters of the Zn-Al-Mg-rare earth alloy coating are adjusted to have a current of 140A and a voltage of 40V, and the rest of the preparation process is the same as that of embodiment 1 to obtain a corrosion-resistant coating.

[0091] The performance of the material prepared in the above embodiment was tested, and the comparison results with those in Example 1 are shown in Table 4.

[0092] Table 4

[0093] Breaking load / N Binding strength / MPa Salt spray resistance time Salt spray-heat exposure cycle Example 1 18395 37.5 ＞6000h 1125 times Example 6 17708 36.1 4000h / Example 7 16776 34.2 ＞6000h 720 times

[0094] It can be seen from the above table that adjusting the arc spraying process current and voltage parameters of the Zn-Al-Mg-rare earth alloy coating has a significant effect on the coating performance, because lower and higher spraying powers will lead to different coating thickness and bonding strength, which in turn affects the salt spray-heat exposure resistance of the coating. According to the results in the above table, the best technical effect can be obtained when the arc spraying process current of the Zn-Al-Mg-rare earth alloy coating in the present invention is 120A and the voltage is 35V.

[0095] In summary, the present invention adds rare earth elements to the traditional inorganic salt aluminum coating, thereby improving the corrosion resistance and oxidation resistance of the inorganic salt aluminum coating. The corrosion products of the Zn-Al-Mg-rare earth alloy coating prepared by the present invention are extremely dense, blocking the corrosion channel, improving the self-sealing effect of the coating, and greatly improving the anti-corrosion performance of the coating; at the same time, the arc-sprayed Zn-Al-Mg-rare earth alloy coating has high density and good comprehensive mechanical properties.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a corrosion-resistant coating for a gas turbine compressor blade, characterized in that: include, The inorganic salt aluminum coating is sprayed on the cleaned blade surface multiple times by air spraying, and dried and solidified to form an inorganic salt aluminum coating; After the inorganic salt aluminum coating is subjected to shot peening and conductive treatment, an arc spraying technology is used to prepare a Zn-Al-Mg-rare earth alloy coating on the surface of the inorganic salt aluminum coating; Wherein, in terms of mass fraction, the Zn-Al-Mg-rare earth alloy coating includes 20-30% Al, 2-8% Mg, 1-3% rare earth elements, and the remaining component is Zn, and the rare earth elements include one or more of Re, Ce, and La elements.

2. The method for preparing the corrosion-resistant coating for gas turbine compressor blades according to claim 1, characterized in that: The inorganic salt aluminum coating is prepared by using water-soluble phosphate and chromate as binders and rare earth aluminum alloy powder as main filler, and includes: After heating a 50-60% H3PO4 solution to 80-90°C, slowly and in batches, add MgO powder until it is completely dissolved while stirring continuously, raise the temperature to 120-150°C, react for 0.5-1.5h, and cool to room temperature after the reaction to form a Mg(H2PO4)2 solution with a pH of 3-3.5; Take MgO powder and slowly add it into a CrO3 aqueous solution with a concentration of 150-350 g / L to react and generate a MgCrO4 solution; Mg(H2PO4)2 solution and MgCrO4 solution are mixed evenly, and then silica sol is added and stirred evenly to obtain a binder, and finally rare earth aluminum alloy powder is added and ultrasonically dispersed and filtered to obtain an inorganic salt aluminum coating; Among them, the mass ratio of H3PO4 and MgO is 2.5-3.5:0.8-1.4; the mass ratio of CrO3 and MgO is 2.2-2.8:0.5-1.

0.

3. The method for preparing the corrosion-resistant coating of a gas turbine compressor blade according to claim 2, characterized in that: The rare earth aluminum alloy powder has a particle size of less than 5 μm and comprises 1.00-10.00% Ce, 0.10-0.50% Y, 0.10-2.50% Zr, and the rest is Al.

4. The method for preparing the corrosion-resistant coating for gas turbine compressor blades according to claim 2, characterized in that: The volume ratio of the silica sol to the mixed solution of Mg(H2PO4)2 and MgCrO4 is 0.3-0.8:1-1.5; the mass ratio of the rare earth aluminum alloy powder to the binder is 0.5-1.2:1.5-2.

2.

5. The method for preparing the corrosion-resistant coating of a gas turbine compressor blade according to claim 1, characterized in that: The air spraying is to dry in the air for 0.5 to 1.2 hours, then transfer to 70 to 90° C. and heat for 0.5 to 1 hour, and then cure at 200 to 350° C. for 0.5 to 3.5 hours.

6. The method for preparing the corrosion-resistant coating of a gas turbine compressor blade according to claim 1, characterized in that: The cleaning treatment comprises using a degreasing and rust removing agent to remove oil and rust from the blade surface, and then ultrasonic cleaning for 0.5 to 1.5 hours; then wet sand blowing is performed using sand larger than 150 meshes, the pressure of the compressed air used is 0.2 to 0.7 MPa, and then ultrasonic cleaning is performed for 0.5 to 1.5 hours, and finally drying; Wherein, the cleaning solution includes one or more of distilled water, anhydrous ethanol or acetone.

7. The method for preparing the corrosion-resistant coating for gas turbine compressor blades according to claim 1, characterized in that: The shot peening treatment uses mixed particles of 20-30 mesh glass shots and corundum sand, the blasting pressure is 45-60N, and after the treatment, the resistance of any area 30mm apart on the coating surface is less than 15Ω.

8. The method for preparing the corrosion-resistant coating of a gas turbine compressor blade according to claim 1, characterized in that: The arc spraying has a current of 100-150A, a voltage of 30-40V, a spraying distance of 120-200mm, and a gas pressure of 0.5-0.8MPa.

9. The method for preparing the corrosion-resistant coating of a gas turbine compressor blade according to claim 1, characterized in that: The thickness of the inorganic salt aluminum coating is 50-100 μm; the thickness of the Zn-Al-Mg-rare earth alloy coating is 100-200 μm.

10. A corrosion-resistant coating for a gas turbine compressor blade prepared by the preparation method according to any one of claims 1 to 9.

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