Preparation Method of Inorganic Phosphate Anticorrosion Coating for Compressor Blades

Abstract

The present invention discloses a preparation method of an inorganic phosphate anti-corrosion coating for a compressor blade, which includes sandblasting, first weighing, automated spraying of the inorganic phosphate anti-corrosion coating, first vibratory finishing, grinding, second weighing, second vibratory finishing, and third weighing in sequence. The present invention can greatly reduce the rework rate of phenomena such as wrinkles, runs, and blisters on the blade body coating caused by manual spraying, better ensure the manufacturing compliance and consistency of the blade body coating, and improve the service performance of the compressor blade in a marine environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressor blade coating preparation, and specifically relates to a preparation process method of an inorganic phosphate anti-corrosion coating for compressor blades. Background Art

[0002] Compressor blades are one of the core components of aeroengines and gas turbines. The compressor needs to provide a stable compressed air flow to the combustion chamber under various complex environments. Aeroengines and ship gas turbines serve in the marine environment. When the engine is parked, the compressor blades are corroded by the continuous action of humidity and salt spray; when the engine is operating, the compressor blades are easily eroded by the continuous scouring of high-temperature, salt-containing and humid air, resulting in thermal corrosion damage and even corrosion cracks. The engine cycles between these two states, and problems such as equipment corrosion, corrosion fatigue, and service life attract attention.

[0003] The inorganic phosphate anti-corrosion coating is a high-temperature resistant coating made by mixing phosphates of alkali metals such as aluminum and magnesium as binders with metals and metal oxides, and its main components are phosphates, aluminum powder and water. In the Chinese invention patent (application number 202111241829.7), a dipping + drying process method is used to prepare the anti-corrosion coating, but this method has poor effect on the inorganic phosphate coating. In addition, there are also some other process methods for preparing inorganic phosphate coatings, which are prone to phenomena such as delamination, powdering, wrinkling, flowing, and foaming, which affect the coating thickness uniformity, excellent roughness, and the appearance of the blades to varying degrees, seriously restricting the production efficiency, anti-corrosion performance, and service life of the compressor blades.

[0004] For the above reasons, it is necessary to design a preparation method suitable for inorganic phosphate anti-corrosion coatings. Summary of the Invention

[0005] The present invention aims to provide a preparation method of an inorganic phosphate anti-corrosion coating for compressor blades, which can better ensure that the sprayed coating thickness, appearance uniformity, and coating flatness meet the design requirements, improve the surface roughness of the coating, and greatly reduce phenomena such as wrinkling, flowing, and foaming in manual spraying.

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

[0007] A preparation method of an inorganic phosphate anti-corrosion coating for compressor blades includes:

[0008] Step 1, sandblasting: degrease the parts of the compressor blade that need to be coated, shield and protect the non-sprayed areas, and then perform sandblasting on the compressor blade;

[0009] Step 2, first weighing: weigh the compressor blade qualified by sandblasting, and record the weighing result as m1, retaining at least two decimal places;

[0010] Step 3, Automatically spray an inorganic phosphate anti-corrosion coating: After protecting the non-sprayed parts of the compressor blades, start the automatic spraying of the inorganic phosphate anti-corrosion coating. After ensuring that a uniform coating is formed on the sprayed parts of the compressor blade surface, put the sprayed compressor blades into a high-temperature oven for coating curing;

[0011] Step 4, First vibratory finishing;

[0012] Step 5, Grinding: Check the appearance of the coating on the compressor blades after the first vibratory finishing. If the coating appearance is uneven (such as small particle bumps, accumulation at the leading and trailing edges and the blade tip, etc.) or there are local non-depth scratches, use a steel eraser or sandpaper (metallographic sandpaper with a grit size of 1000 or above) for grinding. During grinding, cleaning must be carried out simultaneously (i.e., let water flow slowly over the grinding area) to ensure that the residues of the steel eraser or sandpaper do not adhere to the coating surface;

[0013] Step 6, Second weighing: Weigh the ground compressor blades, and record the weighing result as m2, retaining at least two decimal places;

[0014] Step 7, Second vibratory finishing: Select different vibratory finishing durations according to the difference △m21 = m2 - m1 between the second weighing and the first weighing;

[0015] Step 8, Third weighing: Weigh the compressor blades after the second vibratory finishing, and record the weighing result as m3, retaining at least two decimal places. Calculate the difference △m31 = m3 - m1 between the third weighing and the first weighing, and judge whether the coating weight meets the design requirements according to the difference △m31.

[0016] As an alternative, in the said Step 1,

[0017] Remove oil by using a water-based cleaning agent, alcohol, acetone or other methods;

[0018] Use tape, rubber products, metal sheets or special fixtures for masking protection.

[0019] As an alternative, in the said Step 1, after sandblasting, remove the masking, check whether the sandblasted area is consistent with the surface to be sprayed, and inspect the appearance and roughness of the sandblasted surface to see if it is greater than or equal to 3.2 μm.

[0020] As an alternative,

[0021] In the said Step 3, install the compressor blades on a special fixture and cooperate with an automatic spraying device to apply the coating. The special fixture is rotatable, and always keep the nozzle of the automatic spraying device at a 90° angle to the parts of the compressor blades to be sprayed to ensure a uniform coating thickness;

[0022] In the third step, automated spraying is carried out in the following order and trajectory:

[0023] First step, spray on the pressure side of the compressor blade according to the spraying trajectory of pressure side flange → pressure side exhaust edge → pressure side tip → pressure side inlet edge;

[0024] Second step, after spraying on the pressure side flange is completed, turn to the back side flange and continue spraying;

[0025] Third step, spray on the back side of the compressor blade according to the spraying trajectory of back side flange → back side inlet edge → back side tip → back side exhaust edge;

[0026] Fourth step, spray the pressure and back side blade bodies.

[0027] As an alternative, when the nozzle of the automated spraying equipment moves uniformly to approach the part of the compressor blade to be sprayed, gradually increase the flow rate of the inorganic phosphate liquid, and then maintain uniform spraying. When the spraying is about to end, gradually reduce the flow rate of the inorganic phosphate liquid for edge finishing.

[0028] As an alternative, in the fourth step, a bowl-shaped spiral vibration lapping machine is used for the first vibration finishing. According to the different volumes of the bowl-shaped spiral vibration lapping machine, different numbers of compressor blades are placed equidistantly in the abrasive, and it is ensured that the compressor blades are completely immersed in abrasives of different specifications. Then, grinding fluid is added to the abrasive, and then the vibration frequency and vibration duration are selected. Finally, start the bowl-shaped spiral vibration lapping machine to carry out the first vibration finishing on the compressor blades, where:

[0029] For a bowl-shaped spiral vibration lapping machine with a volume of 250L, 80 - 100 compressor blades are placed each time;

[0030] For a bowl-shaped spiral vibration lapping machine with a volume of 600L, 180 - 200 compressor blades are placed each time;

[0031] The abrasive for the first vibration finishing is resin cones, and the resin cone specifications include 5×5, 15×15, 20×20, and 25×25. A single specification of resin cone or a mixture of two or more specifications of resin cones is used.

[0032] As an alternative, during the first vibration finishing, 120 - 180g of grinding fluid is added each time, the vibration frequency is 35 - 45Hz, and the vibration duration is 10 - 25min.

[0033] As an alternative, in the seventh step,

[0034] When △m21 is 0.10 - 0.15g, the vibration finishing duration is 20 - 25min;

[0035] When △m21 is 0.20 - 0.25 g, the vibration finishing time is 35 - 40 min;

[0036] When △m21 is 0.30 - 0.35 g, the vibration finishing time is 48 - 52 min.

[0037] As an alternative, in step seven, the compressor blades are immersed in the abrasive of the bowl - type spiral vibration grinding machine at equal intervals for the second vibration finishing, where:

[0038] For a bowl - type spiral vibration grinding machine with a volume of 250 L, 80 - 100 compressor blades are placed each time;

[0039] For a bowl - type spiral vibration grinding machine with a volume of 600 L, 180 - 200 compressor blades are placed each time;

[0040] The abrasive for the second vibration finishing is inclined - triangle corundum. The specifications of the inclined - triangle corundum include 8×8, 12×12, and 17×17, and a single - specification inclined - triangle corundum or a mixture of two or more specifications of inclined - triangle corundum is used;

[0041] During the second vibration finishing, 300 - 400 g of grinding fluid is added each time;

[0042] During the second vibration finishing, the vibration frequency is 35 - 45 Hz.

[0043] As an alternative, in step eight, the compressor blades with the smallest difference △m31 in each batch are selected for metallographic inspection to measure whether the coating thickness meets the design requirements. If the requirements are met, the compressor blades in this batch are qualified products.

[0044] Compared with the existing preparation process method of inorganic phosphate anti - corrosion coatings for compressor blades, the present invention can greatly reduce the rework rate caused by manual spraying, such as wrinkles, running, and blistering on the blade body coating, better ensure the manufacturing compliance and consistency of the blade body coating, and improve the service performance of compressor blades in the marine environment.

[0045] Specifically, the preparation method of the inorganic phosphate anti - corrosion coating of the present invention has the following advantages:

[0046] (1) Automated spraying: When using automated spraying equipment, the consistency of the spraying thickness can be greatly improved, which is suitable for mass production.

[0047] (2)Vibratory finishing: In the traditional coating preparation method of dip coating + drying, after each spraying, it is necessary to wait for drying and then perform grinding. This method has low efficiency, high labor intensity for operators, and poor product consistency. Vibratory finishing can improve the roughness and consistency of the blade body coating in batches. In addition, after the first vibratory finishing of the sprayed blade, obvious coating defects on the blade body can be quickly detected, and through the grinding process, the coating defects can be effectively eliminated.

[0048] (3)Grinding: It is carried out in a way of grinding while flushing with water. The water flow can carry away the debris generated by the friction between the sandpaper or steel eraser and the coating of the compressor blade, without invading the coating or remaining on the coating.

[0049] (4)Weighing method: Compared with the traditional manual spraying method, after which test pieces are randomly selected for metallographic inspection to determine whether the blades in this batch are qualified. The weighing method in the present invention can control the coating weight on the blades by 100%. After adopting automated spraying, it can further ensure the coating thickness of each blade. Description of the Drawings

[0050] Figure 1 It is the flow chart of the preparation method of the inorganic phosphate anti-corrosion coating of the present invention;

[0051] Figure 2 It is the cross-sectional view of the placement method of the compressor blade in the abrasive of the present invention;

[0052] Figure 3 It is the top view of the placement method of the compressor blade in the abrasive of the present invention;

[0053] Figure 4 It is the schematic diagram of the automated spraying trajectory of the compressor blade in the basin direction in the embodiment of the present invention;

[0054] Figure 5 It is the schematic diagram of the automated spraying trajectory of the compressor blade in the back direction in the embodiment of the present invention.

[0055] Figure 6 It is the spraying schematic diagram of the blade body of the compressor blade in the basin direction in the embodiment of the present invention;

[0056] Figure 7 It is the spraying schematic diagram of the compressor blade flange in the embodiment of the present invention;

[0057] Figure 8 It is the spraying schematic diagram of the blade body of the compressor blade in the back direction in the embodiment of the present invention;

[0058] In the figure: 1 - compressor blade, 2 - vibratory finishing equipment, 3 - abrasive, 4 - blade to be sprayed, 5 - nozzle, 6 - shroud towards the pressure side, 7 - trailing edge towards the pressure side, 8 - leading edge towards the pressure side, 9 - tip towards the pressure side, 10 - shroud towards the suction side, 11 - leading edge towards the suction side, 12 - trailing edge towards the suction side, 13 - tip towards the suction side. Detailed implementation manners

[0059] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, all modifications, substitutions and changes made according to common general knowledge and conventional means in the art are included in the scope of the present invention.

[0060] As Figures 1 to 8 shown, it is a method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade in the present invention, which specifically includes the following steps:

[0061] Step 1, sandblasting (increasing the friction force of the bonding surface of the spraying part): degrease the parts (6 - 13) of the compressor blade 1 that need to be sprayed with a coating, then shield and protect the non-spraying areas. Then, put the compressor blade 1 into a sandblasting machine for sandblasting. Finally, remove the shielding and check whether the sandblasted area is consistent with the surface to be sprayed, and inspect whether the appearance and roughness of the sandblasted surface meet the requirement of ≥3.2 μm. When this roughness is met, the bonding force between the coating and the substrate of the compressor blade 1 is better.

[0062] Preferably, degreasing is carried out by means of a water-based cleaning agent, alcohol, acetone, etc.;

[0063] Preferably, shielding and protection are carried out by means of tape, rubber products, metal sheets, special fixtures, etc.

[0064] Step 2, first weighing: weigh the compressor blade 1 that has passed the sandblasting, and record the weighing result as m1, and two decimal places must be reserved.

[0065] Step 3, automated spraying (spraying a coating that meets the requirements on the blade body and other parts that need to be sprayed): install the blade 4 to be sprayed on a special fixture, protect the non-spraying parts, and then start the automated spraying equipment for spraying. First step, the spraying trajectory on the pressure side of the blade is as Figure 4 shown: shroud towards the pressure side 6 → trailing edge towards the pressure side 7 → tip towards the pressure side 9 → leading edge towards the pressure side 8; Second step, after spraying on the shroud towards the pressure side 6 is completed, turn to the shroud towards the suction side 10 and continue spraying, as Figure 7 shown; Third step, the spraying trajectory on the suction side of the blade is as Figure 5 shown: shroud towards the suction side 10 → leading edge towards the suction side 11 → tip towards the suction side 13 → trailing edge towards the suction side 12; Fourth step, spray the pressure and suction side blade bodies, as Figure 6 、Figure 8 As shown, a uniform coating is formed on the sprayed parts of the surface of the compressor blade 1 (the shroud side flange 6, the shroud side exhaust edge 7, the shroud side inlet edge 8, the shroud side tip 9, the back side flange 10, the back side inlet edge 11, the back side exhaust edge 12, and the back side tip 13), and then the sprayed compressor blade 1 is placed in a high-temperature oven for coating curing.

[0066] Preferably, the special fixture for installing the blade 4 to be sprayed is rotatable and can always make the nozzle 5 of the automatic spraying equipment form a 90° angle with the part to be sprayed of the blade 4 to be sprayed, as shown in Figures 6 to 8 to ensure a consistent coating thickness.

[0067] Preferably, when the nozzle 5 moves uniformly to approach the part to be sprayed of the blade 4 to be sprayed, the flow rate of the inorganic phosphate liquid is gradually increased, and then, uniform spraying is maintained. When the spraying is about to end, the flow rate of the inorganic phosphate liquid is gradually decreased for edging.

[0068] Step Four: First vibratory finishing (to expose the defects of the coating in the sprayed area): According to the different volumes of the vibratory finishing equipment 2 of different models (a bowl-type spiral vibratory grinding machine is selected in this embodiment), different numbers of compressor blades 1 are placed equidistantly in the abrasive 3, and it is ensured that the compressor blades 1 are completely immersed in the abrasives 3 of different specifications. Then, grinding fluid is added to the abrasive 3, and then the vibration frequency and vibration duration are selected. Finally, the vibratory finishing equipment 2 is started to perform vibratory finishing on the compressor blades 1.

[0069] Preferably, for a bowl-type spiral vibratory grinding machine with a volume of 250 L, 80 - 100 compressor blades 1 are placed each time;

[0070] Preferably, for a bowl-type spiral vibratory grinding machine with a volume of 600 L, 180 - 200 compressor blades 1 are placed each time;

[0071] Preferably, the abrasive 3 for the first vibratory finishing is resin cones, and the resin cone specifications are 5×5, 15×15, 20×20, 25×25, etc. In this embodiment, the aforementioned four specifications of resin cones are mixed. The effect of mixing multiple specifications is better, and the ratio of different specifications is adjusted according to the test results. The mixing of multiple specifications has a substantial impact on the quality of the coating. For example, the ratio can be selected as 3:3:2:1 or 4:2:2:1. When the abrasive has been used for 20 hours, the ratio of various abrasives is judged in the following way: In the uniformly vibrating abrasive, randomly fill a 2 L bucket with the abrasive at one time, and then screen out various sizes of abrasives. When the specifications of each abrasive do not meet the above ratio, replenish them according to the above ratio and then continue to use;

[0072] Preferably, 120 - 180 g of grinding fluid is added each time;

[0073] Preferably, the vibration frequency is 35 - 45 Hz, the vibration duration is 10 - 25 min, and the grinding fluid is LM - 10.

[0074] Step Five, grinding (adopting the method of grinding while washing with water to eliminate coating defects): Check the coating appearance of the compressor blade 1 after the first vibratory finishing. If the coating appearance is uneven (such as small particle bumps, accumulation at the leading and trailing edges and the tip, etc.), or there are local non - deep scratches, a steel eraser or metallographic sandpaper with a grit size of more than 1000 meshes can be used for grinding. During grinding, cleaning must be carried out simultaneously, that is, let the water flow slowly rinse the grinding area to ensure that the residues of the steel eraser or metallographic sandpaper do not adhere to the blade coating.

[0075] Step Six, second weighing: Weigh the ground compressor blade 1, and record the weighing result as m2, which must be reserved to two decimal places.

[0076] Step Seven, second vibratory finishing (to increase the surface roughness of the coating): Immerse a certain number of compressor blades 1 into the abrasive in the bowl - type spiral vibration grinding machine at equal intervals, and select an appropriate vibratory finishing duration according to the difference △m21 = m2 - m1 between the second weighing and the first weighing. For example:

[0077] When △m21 is 0.10 - 0.15 g, the vibratory finishing duration is 20 - 25 min;

[0078] When △m21 is 0.20 - 0.25 g, the vibratory finishing duration is 35 - 40 min;

[0079] When △m21 is 0.30 - 0.35 g, the vibratory finishing duration is 48 - 52 min.

[0080] Preferably, for a bowl - type spiral vibration grinding machine with a volume of 250 L, 80 - 100 compressor blades 1 are placed each time;

[0081] Preferably, for a bowl - type spiral vibration grinding machine with a volume of 600 L, 180 - 200 compressor blades 1 are placed each time;

[0082] Preferably, the abrasive 3 for the second vibratory finishing is obliquely triangular corundum, and the specifications of the obliquely triangular corundum are 8×8, 12×12, 17×17, etc. In this embodiment, the above three specifications of obliquely triangular corundum are mixed. The effect of mixing multiple specifications is better, and the ratio of different specifications is adjusted according to the test effect. The mixing of multiple specifications has a substantial impact on the quality of the coating. For example, the ratio can be selected as 4:1:1 or 3:2:1. After the abrasive is used for 5 hours, judge the proportion of various abrasives in the following way: Randomly fill 2L buckets with the abrasive in a uniform vibration state, and then screen out various sizes of abrasives. When the abrasives of each specification do not meet the above ratio, replenish them according to the above ratio and then continue to use;

[0083] Preferably, 300 - 400 g of grinding fluid is added each time for the second vibratory finishing;

[0084] Preferably, the vibration frequency of the second vibratory finishing is 35 - 45 Hz.

[0085] Step Eight, the third weighing (to obtain whether the thickness of the coating sprayed on the blade meets the design requirements): Weigh the compressor blade 1 that has undergone the second vibratory finishing, and record the weighing result as m3, which must be reserved to two decimal places. Calculate whether the difference △m31 = m3 - m1 between the third weighing and the first weighing meets the coating weight specified by the design. And select the compressor blade 1 with the smallest weight difference △m31 in each batch of compressor blades 1 for metallographic inspection to confirm whether the coating thickness meets the design requirements. If the requirements are met, this batch of compressor blades 1 is qualified blades.

[0086] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art. Although the above specific embodiments describe the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the technical field, as long as various changes fall within the scope defined by the claims, they all belong to the protection scope of the present invention.

Claims

1. A method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade, characterized in that: including Step 1, sandblasting: degrease the parts of the compressor blade that need to be coated, shield and protect the non-sprayed areas, and then perform sandblasting on the compressor blade; Step 2, first weighing: weigh the compressor blade that has passed the sandblasting, record the weighing result as m1, and retain at least two decimal places; Step 3, automatically spray the inorganic phosphate anti-corrosion coating: after protecting the non-sprayed parts of the compressor blade, start the automatic spraying of the inorganic phosphate anti-corrosion coating. After ensuring that a uniform coating is formed on the sprayed parts of the compressor blade surface, put the sprayed compressor blade into a high-temperature oven for coating curing; Step 4, first vibratory finishing; Step 5, grinding: check the coating appearance of the compressor blade after the first vibratory finishing. If the coating appearance is uneven or there are local non-depth scratches, use a steel eraser or sandpaper for grinding. During grinding, cleaning must be carried out simultaneously to ensure that the residues of the steel eraser or sandpaper do not adhere to the coating surface; Step 6, second weighing: weigh the compressor blade after grinding, record the weighing result as m2, and retain at least two decimal places; Step 7, second vibratory finishing: select different vibratory finishing durations according to the difference △m21 = m2 - m1 between the second weighing and the first weighing; Step 8, third weighing: weigh the compressor blade after the second vibratory finishing, record the weighing result as m3, and retain at least two decimal places. Calculate the difference △m31 = m3 - m1 between the third weighing and the first weighing, and judge whether it meets the coating weight specified by the design according to the difference △m31.

2. The method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, wherein: In the above Step 1, use a water-based cleaning agent, alcohol or acetone for degreasing; use tape, rubber products, metal sheets or special fixtures for shielding and protection.

3. The method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, characterized in that: In the above Step 1, after sandblasting, remove the shield, check whether the sandblasted area is consistent with the surface to be sprayed, and inspect the appearance and roughness of the sandblasted surface to see if it is greater than or equal to 3.2 μm.

4. The method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, characterized in that: In the above Step 3, install the compressor blade on a special fixture and cooperate with an automatic spraying device to perform coating spraying. The special fixture is rotatable, and always keep the nozzle of the automatic spraying device at a 90° angle to the part of the compressor blade to be sprayed to ensure the consistency of the coating thickness; In the above Step 3, perform automatic spraying in the following order and trajectory: The first step, spray on the compressor blade's pressure side according to the spraying trajectory of pressure side flange → pressure side exhaust edge → pressure side tip → pressure side inlet edge; The second step, after spraying on the pressure side flange is completed, turn to the suction side flange and continue spraying; The third step, spray on the compressor blade's suction side according to the spraying trajectory of suction side flange → suction side inlet edge → suction side tip → suction side exhaust edge; The fourth step, spray the pressure and suction side blade bodies.

5. The method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade according to claim 4, characterized in that: When the nozzle of the automatic spraying device moves uniformly close to the part of the compressor blade to be sprayed, gradually increase the flow rate of the inorganic phosphate liquid, and then keep spraying at a constant speed. When the spraying is about to end, gradually reduce the flow rate of the inorganic phosphate liquid for edge finishing.

6. The preparation method of the inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, characterized in that: In the fourth step, a bowl-shaped spiral vibration grinding machine is used for the first vibration finishing. According to the different volumes of the bowl-shaped spiral vibration grinding machine, different numbers of compressor blades are evenly placed in the abrasive, and it is ensured that the compressor blades are completely immersed in abrasives of different specifications. Then, grinding fluid is added to the abrasive, and then the vibration frequency and vibration duration are selected. Finally, the bowl-shaped spiral vibration grinding machine is started to perform the first vibration finishing on the compressor blades, where: For a bowl-shaped spiral vibration grinding machine with a volume of 250L, 80 - 100 compressor blades are placed each time; For a bowl-shaped spiral vibration grinding machine with a volume of 600L, 180 - 200 compressor blades are placed each time; The abrasive for the first vibration finishing is resin cones, and the resin cone specifications include 5×5, 15×15, 20×20, and 25×25. A single specification of resin cones or a mixture of two or more specifications of resin cones is used.

7. The preparation method of the inorganic phosphate anti-corrosion coating for the compressor blade according to claim 6, characterized in that: During the first vibration finishing, 120 - 180g of grinding fluid is added each time, the vibration frequency is 35 - 45Hz, and the vibration duration is 10 - 25min.

8. The preparation method of the inorganic phosphate anti-corrosion coating for the compressor blade according to claim 1, characterized in that: In the seventh step, When △m21 is 0.10 - 0.15g, the vibration finishing duration is 20 - 25min; When △m21 is 0.20 - 0.25g, the vibration finishing duration is 35 - 40min; When △m21 is 0.30 - 0.35g, the vibration finishing duration is 48 - 52min.

9. The preparation method of the inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, wherein: In the seventh step, the compressor blades are immersed in the abrasive of the bowl-shaped spiral vibration grinding machine at equal intervals for the second vibration finishing, where: For a bowl-shaped spiral vibration grinding machine with a volume of 250L, 80 - 100 compressor blades are placed each time; For a bowl-shaped spiral vibration grinding machine with a volume of 600L, 180 - 200 compressor blades are placed each time; The abrasive for the second vibration finishing is oblique triangular corundum, and the oblique triangular corundum specifications include 8×8, 12×12, and 17×17. A single specification of oblique triangular corundum or a mixture of two or more specifications of oblique triangular corundum is used; During the second vibration finishing, 300 - 400g of grinding fluid is added each time; During the second vibration finishing, the vibration frequency is 35 - 45Hz.

10. The method for preparing an inorganic phosphate anti-corrosion coating for a compressor blade according to claim 1, wherein: In the eighth step, select the compressor blades with the smallest difference △m31 in each batch for metallographic inspection, and measure whether the coating thickness meets the design requirements. If the requirements are met, the compressor blades in this batch are qualified products.

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