Nickel-silicon-boron nitride abradable sealing coating, application and preparation method of nickel-silicon-boron nitride abradable sealing coating

Abstract

The invention discloses a nickel-silicon-boron nitride abradable sealing coating and application and a preparation method thereof, the abradable sealing coating comprises a bottom layer material in direct contact with a base material and a surface layer material located on the surface of the bottom layer material, the bottom layer material is nickel-chromium alloy, and the surface layer material is nickel-silicon-boron nitride. When the coating is prepared, automatic plasma spraying equipment is adopted, firstly, nickel-chromium alloy powder is adopted as a bottom layer material to be sprayed on the surface of a base material, and then nickel-silicon-boron nitride powder is adopted as a surface layer material to be sprayed on the surface of the bottom layer material. The prepared nickel-silicon-boron nitride abradable sealing coating can be applied to low-pressure turbine discs, high-pressure turbine guiders and sealing seats of aero-engines and gas turbines. According to the method, a traditional manual flame spraying operation mode is replaced, the safety is improved, the material utilization rate and the spraying efficiency are improved, the preparation period is shortened, the material cost is reduced, and the structure property, the bonding strength and the thermal shock resistance of the abradable seal coating are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coating preparation, and in particular relates to a method for preparing a nickel silicon boron nitride (NiSi / BN) abradable sealing coating by using plasma spraying equipment. Background Art

[0002] At present, the domestic method of processing nickel silicon boron nitride (NiSi / BN) coating is traditional manual flame spraying of rods, using GH3030 wire as the base, and the operator holds the spray gun for processing, which cannot realize spraying automation. In recent years, the coating technology of aircraft engines and gas turbines has tended to develop in the direction of automation, efficiency and complexity. The traditional manual processing method is increasingly unable to meet the requirements of high-quality, efficient and low-cost preparation.

[0003] The coating surface prepared by manual flame spraying of nickel silicon boron nitride rods is prone to large unmelted particles, requiring the operator to constantly scrape the large surface particles manually. Due to the frequent cleaning of unmelted particles and rod wire changing operations, the spraying process is paused for a long time and continuous processing cannot be achieved. At the same time, affected by the skill levels of different operators, the coating quality is difficult to guarantee and the product quality consistency is poor. At the same time, the labor intensity of manual spraying operators is high, and the operators are exposed to the spraying environment. There is a risk of deflagration every time the manual ignition starts. The working environment is harsh and the operation is highly dangerous. In addition, due to the bending and deformation of the rod, the spraying process is prone to backfire and the rod breaks, resulting in problems such as discontinuous spraying process, low spraying efficiency, and high coating rework rate. Summary of the invention

[0004] The present invention aims to provide a nickel silicon boron nitride abradable sealing coating, its application and its preparation method, which can replace the traditional manual flame spraying operation mode, improve safety and spraying efficiency, shorten the preparation cycle, improve material utilization, reduce material cost, improve the quality consistency and qualified rate of the abradable sealing coating, and improve the organizational properties, bonding strength and thermal shock resistance of the abradable sealing coating.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A nickel silicon boron nitride abradable sealing coating comprising:

[0007] A bottom material in direct contact with the base material, wherein the bottom material is a nickel-chromium alloy;

[0008] The surface layer material is located on the surface of the bottom layer material, and the surface layer material is nickel silicon boron nitride.

[0009] As an option, the base material is stainless steel or high temperature alloy.

[0010] As a solution, in the nickel-chromium alloy, the mass percentage of each component is:

[0011] Cr: 18.5%~20.5%;

[0012] Si: ≤0.5%;

[0013] Mo: ≤0.5%;

[0014] Fe: ≤1.0%;

[0015] The remainder is Ni.

[0016] As a solution, the mass percentage of each component in the nickel silicon boron nitride is:

[0017] Al: 0.2%~1.0%;

[0018] C: 1.0%~2.0%;

[0019] BN: 7.0%~12.0%;

[0020] SiO2: 4.0%~11.0%;

[0021] The remainder is Ni.

[0022] The nickel silicon boron nitride abradable sealing coating is used in low-pressure turbine disks, high-pressure turbine guide vanes and sealing seats of aircraft engines and gas turbines.

[0023] A method for preparing a nickel silicon boron nitride abradable sealing coating, comprising:

[0024] Use automated plasma spraying equipment;

[0025] Firstly, nickel-chromium alloy powder is used as the bottom layer material and sprayed on the surface of the base material, and then nickel silicon boron nitride powder is used as the surface layer material and sprayed on the surface of the bottom layer material.

[0026] Furthermore, the particle size of the nickel-chromium alloy powder is 45 μm to 106 μm.

[0027] Furthermore, the powder particle size of the nickel silicon boron nitride powder is 45 μm to 270 μm.

[0028] Further, the method for preparing the nickel silicon boron nitride abradable sealing coating also includes:

[0029] Preparation steps before plasma spraying: drying the nickel-chromium alloy powder and nickel-silicon-boron-nitride powder, and cleaning the surface to be sprayed, including degreasing;

[0030] Sand blasting treatment steps: first cover and protect the non-sprayed surface, then perform sand blasting on the sprayed surface. The sand blasting pressure is 0.2MPa~0.5MPa, the sand blasting distance is 100mm~200mm, and the sand blasting angle is 60°~75°.

[0031] As a scheme, in the process of using nickel-chromium alloy powder as the bottom layer material to be sprayed on the surface of the base material, the current of the automated plasma spraying equipment is 440A-460A, the power is 28kW-31kW, the hydrogen flow rate is 7NLPM-9NLPM, the argon flow rate is 40NLPM-50NLPM, the spraying distance is 100mm-130mm, the powder feeding amount is 50g / min-102g / min, and the bottom layer thickness is ≥0.10mm;

[0032] In the process of using nickel silicon boron nitride powder as the surface layer material and spraying it on the surface of the bottom layer material, the current of the automated plasma spraying equipment is 540A-560A, the power is 33kW-36kW, the hydrogen flow rate is 6NLPM-10NLPM, the argon flow rate is 46NLPM-50NLPM, the spraying distance is 100mm-130mm, the powder feeding amount is 44g / min-54g / min, and the surface layer thickness is ≥0.50mm.

[0033] Compared with the prior art, the present invention adopts automated plasma equipment to spray nickel silicon boron nitride powder instead of manual flame spraying to prepare nickel silicon boron nitride abradable sealing coating, thereby solving the problems of low coating spraying efficiency and unstable quality, and high requirements on workers' skill level in the prior art. Furthermore, the coating is applied to materials such as high-temperature alloys and stainless steel, and is promoted to be applied to low-pressure turbine discs, high-pressure turbine guides, sealing seats and other components of aircraft engines and gas turbines.

[0034] The coating prepared by the present invention has high bonding strength, hardness, good abradability and thermal shock resistance, has a dynamic sealing function, and can be widely used in the gas path sealing of aircraft engines and gas turbines to improve the power and efficiency of engines and gas turbines and reduce fuel consumption.

[0035] Compared with the prior art, the present invention uses automated plasma spraying equipment to replace manual flame spraying methods. The operation process is stable, the quality is good and the efficiency is high. The skill level of the workers is not high. The processing process can be automated and can meet all design requirements. The advantages of the present invention include:

[0036] (1) It realizes automatic control and replaces manual flame spraying operation. There is no ignition, deflagration, spray gun backfire, etc. in the spraying process, and the spraying process has a high safety factor.

[0037] (2) Mechanical automated spraying is far more efficient than manual spraying. Manual flame spraying requires two people to work together, while automatic spraying equipment only requires one person to operate, saving labor. In addition, the spraying process is continuous, without the need to stop the gun to change wires or clean the coating, thus shortening the production cycle of component spray coating.

[0038] (3) Plasma spraying uses powder materials, and the melting deposition efficiency is higher than that of rods. There is no material loss and waste caused by rod breakage during the non-spraying process. The material utilization rate is high, which can reduce material costs by 40% to 45%.

[0039] (4) The coating quality of automated plasma spraying is consistent, the process is continuous, there is no need to stop the gun for changing wires and cleaning coatings during manual spraying operations, the coating thickness is uniform, there is no inclusion of unmelted particles, and the one-time processing pass rate is over 95%, which is much higher than the 50% pass rate of manual spraying.

[0040] (5) The coating microstructure prepared by automated plasma spraying has good performance, with a coating microstructure porosity of 1% to 5% and a maximum pore diameter of 5 μm to 20 μm, which is better than the manual flame spray coating microstructure porosity of 3% to 10% and a maximum pore diameter of 10 μm to 25 μm.

[0041] (6) The bonding strength of the coating prepared by automated plasma spraying is higher than that of manual flame spraying, and the average bonding strength is 1Mpa to 2Mpa higher than that of manual flame spraying.

[0042] (7) The thermal shock resistance of the coating prepared by automated plasma spraying is better than that of manual flame spraying. The water cooling method was used for the test. The prepared sample was heated to the specified temperature, kept warm for 5 minutes, and then immersed in water at 20℃±5℃ for one cycle. After 5 cycles at 500℃, the coating prepared by manual flame spraying did not fall off or crack. After 15 cycles at 700℃, the coating prepared by automated plasma spraying did not fall off or crack. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 These are the surface and cross-sectional morphology photos of nickel silicon boron nitride powder for spraying;

[0044] Figure 2 This is a metallographic photograph of a plasma sprayed nickel silicon boron nitride coating;

[0045] Figure 3 These are macroscopic photos of plasma sprayed nickel silicon boron nitride coatings, where the left picture shows the sprayed state and the right picture shows the state after machining. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to common technical knowledge and customary means in the field are included in the scope of the present invention.

[0047] In order to realize the automatic spraying of nickel silicon boron nitride abradable sealing coating, the solution of the present invention is as follows:

[0048] 1. Use nickel-chromium alloy (NiCr) powder suitable for plasma spraying as the base powder instead of GH3030 wire used for manual flame spraying.

[0049] 2. As the base material, the nickel-chromium alloy coating has a similar expansion coefficient to stainless steel and high-temperature alloys, which can ensure high bonding strength between the substrate and the nickel-silicon-boron-nitride surface material and good thermal shock resistance.

[0050] 3. The mass percentage of the nickel-chromium alloy bottom layer powder composition is: Cr (18.5% to 20.5%), Si≤0.5%, Mo≤0.5%, Fe≤1.0%, Ni balance, the sum of each component is 100%, and the powder particle size is 45μm to 106μm.

[0051] 4. Use nickel silicon boron nitride (NiSi / BN) powder suitable for plasma spraying as the surface layer instead of nickel silicon boron nitride rods used for manual flame spraying.

[0052] 5. Nickel silicon boron nitride surface layer powder composition mass percentage: Al (0.2% ~ 1.0%), C (1.0% ~ 2.0%), BN (7.0% ~ 12.0%), SiO2 (4.0% ~ 11.0%), Ni balance, the sum of each component is 100%, the powder particle size is 45μm ~ 270μm, Figure 1 The powder and cross-sectional microstructures of nickel silicon boron nitride surface layer powder are shown in the figure.

[0053] 6. Use plasma spraying of nickel-chromium alloy powder instead of manual flame spraying of GH3030 wire to achieve automatic spraying equipment to spray the bottom layer.

[0054] 7. Use plasma spraying of nickel silicon boron nitride powder instead of manual flame spraying of nickel silicon boron nitride rods to realize the preparation of nickel silicon boron nitride sealing coating by automated spraying equipment.

[0055] A method for preparing a nickel silicon boron nitride abradable sealing coating mainly comprises the following steps:

[0056] Step 1: Preparation before spraying:

[0057] Before using the powder for spraying, it needs to be dried in an oven at (100-120)℃ for more than 1 hour. Before sandblasting and spraying, the drain valve of the oil-water separator in the compressed air pipeline must be opened to drain until the water is released. Visually check that no visible water mist is sprayed out. Use a brush (or cotton wool) dipped in acetone, anhydrous ethanol or other solvents to carefully scrub the parts to thoroughly remove oil and other dirt on the surface of the parts. After degreasing the parts, blow dry or air dry them with clean compressed air.

[0058] Step 2: Sand blasting:

[0059] Use special fixtures or spray protection tape to protect the non-sprayed surface of the parts; sandblast the surface of the parts to be sprayed, the sandblasting pressure is (0.2~0.5)MPa, the sandblasting distance is (100~200)mm, and the sandblasting angle is 60°~75°.

[0060] Step 3: Preparation of Ni-Cr alloy base layer:

[0061] The nickel-chromium alloy base layer was prepared by automated plasma spraying equipment, with a current of (440-460) A, a power of (28-31) kW, a hydrogen flow rate of (7-9) NLPM, an argon flow rate of (40-50) NLPM, a spraying distance of (100-130) mm, a powder feed rate of (50-102) g / min, and a recommended base layer thickness of (0.10-0.20) mm.

[0062] Step 4: Preparation of nickel silicon boron nitride surface layer:

[0063] The nickel silicon boron nitride surface layer is prepared by spraying using automated plasma equipment, with a current of (540-560) A, a power of (33-36) kW, a hydrogen flow rate of (6-10) NLPM, an argon flow rate of (46-50) NLPM, a spraying distance of (100-130) mm, a powder feed rate of (44-54) g / min, and a recommended surface layer thickness of (0.50-1.20) mm.

[0064] In the above-mentioned method for preparing the nickel silicon boron nitride abradable sealing coating, the operation time interval of each step from step 2 to step 4 is no more than 2 hours. The coating is prepared by automated plasma spraying equipment, and the coating quality and performance can be controlled by adjusting the process parameters and the spraying process.

[0065] Example:

[0066] The coating was prepared using the Meike MultiCoat atmospheric plasma spraying equipment, and the spray gun was a F4 conventional spray gun. The specific implementation of the present invention is described below in conjunction with the accompanying drawings:

[0067] S1, powder drying: the powder needs to be dried at (100-120)℃ for more than 1h before use. Spread the nickel-chromium alloy powder and nickel-silicon-boron-nitride powder on a tray with a lid, and dry them in an oven set at 110℃ for 1.5h. The dried powder should be stored in an oven or a special dryer before use.

[0068] S2, Parts degreasing: Use a brush or cotton wool dipped in acetone or anhydrous ethanol or other solvents to carefully scrub the sprayed surface of the parts to thoroughly remove the oil and other dirt on the surface of the parts; after degreasing the parts, blow dry with clean compressed air or dry them in the air.

[0069] S3, Parts protection: Use spray protection tape or special tooling to protect the non-sprayed surfaces of parts.

[0070] S4, Parts Sand Blowing: Sand blast the surface of the part to be sprayed, the sand blasting pressure is 0.3MPa, the sand blasting distance is 160mm, and the sand blasting angle is 75°. When sand blasting, the spray gun is not allowed to be fixed in one place to avoid deformation or over-blowing of the parts. After sand blasting, use compressed air to remove sand particles and dust on the surface of the parts. Visual inspection of the sand blasting surface should be a uniform, matte and rough surface, and no leakage is allowed. It is strictly forbidden to touch the sand blasting surface with bare hands, and sweat is prohibited from contacting the surface of the parts.

[0071] S5, spraying the bottom layer: Use MultiCoat plasma spraying equipment to prepare the nickel-chromium alloy bottom layer. Spray the nickel-chromium alloy bottom layer on the parts within 2 hours after sandblasting. Preheat the parts before processing. Spray the parts in the air twice without powder feeding, or put the parts in an oven for preheating. The preheating temperature is (80-100)°C and take them out before processing. The set nickel-chromium alloy bottom layer spraying process parameters are: current 450A, spraying power 30kW, hydrogen flow 8NLPM, argon flow 45NLPM, spraying distance 120mm, powder feeding plate speed 25%. The thickness of the spray bottom layer is 0.11mm. Turn on the cooling air during spraying to prevent overheating of the parts.

[0072] S6, spraying surface layer: Use MultiCoat plasma spraying equipment to prepare nickel silicon boron nitride surface layer. Immediately after the base layer is sprayed, the parts are sprayed with nickel silicon boron nitride surface layer, and the interval time should not exceed 2h. The set nickel silicon boron nitride surface layer spraying process parameters are: current 550A, spraying power 35kW, hydrogen flow 8NLPM, argon flow 48NLPM, spraying distance 120mm, powder feeding plate speed 50%. The spray surface layer thickness is 4.06mm, such as Figure 2 As shown in the figure, a 4.06mm top layer was sprayed on the basis of a 0.11mm bottom layer, and the total coating thickness was 4.17mm. During the spraying process, the cooling air was turned on to prevent the parts and coating from overheating.

[0073] S7, parts cleaning: remove the parts from the turntable, remove the protective tape or protective tooling, use an oilstone to remove excess coating, and then clean the surface. Pay attention to protecting the part substrate and coating from damage.

[0074] S8, Product Inspection: Visually inspect the appearance of parts. The coating color should be uniform and consistent, without overheating or overburning. The coating should be complete, the surface should be uniform and continuous, without defects such as cracks, peeling, delamination and edge warping. Metallographic structure, bonding strength, surface hardness, and thermal shock resistance tests should be carried out. Products will be issued after the test results are qualified. Figure 3 The figure shows the local macroscopic morphology of the parts after plasma spraying of nickel silicon boron nitride coating. The left picture shows the spraying state, and the right picture shows the state after turning.

[0075] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For the ordinary technical personnel in the field, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A nickel silicon boron nitride abradable sealing coating, characterized in that: include: A bottom material in direct contact with the base material, wherein the bottom material is a nickel-chromium alloy; The surface layer material is located on the surface of the bottom layer material, and the surface layer material is nickel silicon boron nitride.

2. A nickel silicon boron nitride abradable sealing coating according to claim 1, characterized in that: The matrix material is stainless steel and high-temperature alloy.

3. A nickel silicon boron nitride abradable sealing coating according to claim 1, characterized in that: In the nickel-chromium alloy, the mass percentage of each component is: Cr：18.5％～20.5％； Si: ≤0.5%; Mo: ≤0.5%; Fe: ≤1.0%; The remainder is Ni.

4. The nickel silicon boron nitride abradable sealing coating according to claim 1, characterized in that: In the nickel silicon boron nitride, the mass percentage of each component is: Al：0.2％～1.0％； C：1.0％～2.0％； BN: 7.0%~12.0%; SiO2: 4.0%~11.0%; The remainder is Ni.

5. The nickel silicon boron nitride abradable sealing coating as claimed in claim 1, 3 or 4 is used in low-pressure turbine disks, high-pressure turbine guide vanes and sealing seats of aircraft engines and gas turbines.

6. A method for preparing a nickel silicon boron nitride abradable sealing coating, characterized in that: include: Use automated plasma spraying equipment; Firstly, nickel-chromium alloy powder is used as the bottom layer material and sprayed on the surface of the base material, and then nickel silicon boron nitride powder is used as the surface layer material and sprayed on the surface of the bottom layer material.

7. The method for preparing a nickel silicon boron nitride abradable sealing coating according to claim 6, characterized in that: The particle size of the nickel-chromium alloy powder is 45 μm to 106 μm.

8. The method for preparing a nickel silicon boron nitride abradable sealing coating according to claim 6, characterized in that: The powder particle size of the nickel silicon boron nitride powder is 45 μm to 270 μm.

9. The method for preparing a nickel silicon boron nitride abradable sealing coating according to claim 6, characterized in that: Also includes: Preparation steps before plasma spraying: drying the nickel-chromium alloy powder and nickel-silicon-boron-nitride powder, and cleaning the surface to be sprayed, including degreasing; Sand blasting treatment steps: first cover and protect the non-sprayed surface, then perform sand blasting on the sprayed surface. The sand blasting pressure is 0.2MPa~0.5MPa, the sand blasting distance is 100mm~200mm, and the sand blasting angle is 60°~75°.

10. The method for preparing a nickel silicon boron nitride abradable sealing coating according to claim 6, characterized in that: In the process of using nickel-chromium alloy powder as the bottom layer material to spray on the surface of the base material, the current of the automated plasma spraying equipment is 440A-460A, the power is 28kW-31kW, the hydrogen flow rate is 7NLPM-9NLPM, the argon flow rate is 40NLPM-50NLPM, the spraying distance is 100mm-130mm, the powder feeding amount is 50g / min-102g / min, and the bottom layer thickness is ≥0.10mm; In the process of using nickel silicon boron nitride powder as the surface layer material and spraying it on the surface of the bottom layer material, the current of the automated plasma spraying equipment is 540A-560A, the power is 33kW-36kW, the hydrogen flow rate is 6NLPM-10NLPM, the argon flow rate is 46NLPM-50NLPM, the spraying distance is 100mm-130mm, the powder feeding amount is 44g / min-54g / min, and the surface layer thickness is ≥0.50mm.

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