Preparation and application method of cobalt chromium tungsten-nickel aluminum high-temperature wear-resistant coating

Abstract

The invention relates to preparation and application methods of a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating, powder for preparing the coating is cobalt-chromium-tungsten powder and nickel-aluminum powder, and the cobalt-chromium-tungsten powder and the nickel-aluminum powder are mixed according to the mass ratio of 1: 1 to prepare composite powder; and the melting state of the powder is improved by utilizing the self-heat-release characteristic of the nickel-aluminum powder, so that the bonding strength of the coating and a matrix is improved while the hardness of the coating is not reduced, and the deposition efficiency of the coating can be improved. According to the technical scheme, an automatic plasma spraying means is adopted for coating, the spraying cost is low, and the efficiency is high. The coating is suitable for a part coating at the temperature below 750 DEG C, and has good wear resistance, bonding strength, oxidation resistance and adhesion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine coating materials, and in particular to a preparation method of a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating and an application method thereof. Background Art

[0002] Wear-resistant coatings are used on some wear parts with relative motion, usually to resist abrasive wear, adhesive wear, erosion wear, etc. The main materials are tungsten carbide, chromium carbide, aluminum oxide / titanium oxide, etc. Different types of coatings are selected and the coating preparation methods are different under different operating temperatures and different operating conditions. Wear-resistant coatings are usually prepared by plasma spraying, supersonic spraying and explosion spraying. Compared with the other two methods, plasma spraying has low equipment investment and operating costs, a wide range of sprayable materials, and is more widely used in the market.

[0003] The outer ring of the low-pressure guide vane of a certain type of aircraft engine is equipped with 15 grooves with a width of 10 mm, which are used to cooperate with the low-pressure guide vane for installation and to position the vane. The temperature of the parts at this position is relatively high and the operating conditions are harsh. The coating is required to have high hardness, strength and anti-adhesion properties at high temperatures. Conventional wear-resistant coatings cannot meet the requirements. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating and its application; the specific technical scheme is as follows:

[0005] A method for preparing a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating, wherein the powder for preparing the coating is cobalt-chromium-tungsten powder and nickel-aluminum powder, and the two powders are mixed in a mass ratio of 1:1 to prepare a composite powder;

[0006] The cobalt-chromium-tungsten powder has a Co content of 50-58%, a Cr content of 24.5-26.5%, a W content of 7.2-8.2%, a Ni content of 9.5-11.5%, a C content of 0.8-0.9%, a Mn and Si content of no more than 0.5%, a B content of no more than 0.01%, and a Fe content of no more than 2.0%; the particle size distribution is +105μm≤2%, -105μm~+45μm≥95%, -45μm≤3%;

[0007] The nickel aluminum powder has a Ni content of 88-90%, an Al content of 8-11%, a free nickel content of less than 1%, and a total impurity content of less than 1%; the particle size distribution is +90 μm≤5%, -90 μm to +45 μm≥85%, and -45 μm≤10%.

[0008] An application method of a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating comprises the following steps:

[0009] Step 1: Spread the cobalt-chromium-tungsten and nickel-aluminum powders on a covered tray respectively, and dry them in an oven set at 80°C for 1 hour. The dried powders are stored in an oven or other dry container before use. Before use, the cobalt-chromium-tungsten powder and the nickel-aluminum powder are mixed at a mass ratio of 1:1 to prepare the composite powder; stir thoroughly for 20 minutes to ensure the uniformity of the powder;

[0010] Step 2: Use absorbent cotton or a brush dipped in acetone to carefully wipe and clean the spraying area and adjacent areas of the parts to thoroughly remove the oil stains on the surface of the parts; use compressed air to blow dry, and wear clean gloves to touch the parts to avoid secondary contamination of the parts;

[0011] Step 3: Use special tooling or pressure-sensitive tape to protect the non-spraying area. After confirming that the protection is effective, use a pressure sandblasting machine to blow sand. After sandblasting, use clean compressed air to blow away the floating dust on the surface of the parts after sandblasting.

[0012] Step 4: The coating is prepared by automated plasma spraying. The robot holds the spray gun, and the running program is linked with the spray equipment, which can be started with one button. The parts are preheated with the spray gun. The time interval between sand blowing and each coating spraying shall not exceed 2 hours. The spraying area shall be cleaned with compressed air before each spraying.

[0013] Step 5: The spray coating process parameters are: argon flow rate 42.5-47.2 L / min, hydrogen flow rate 4.7-6.1 L / min, current 450-510 A, powder feeding rate 30-45 g / min, spraying distance 130-145 mm, and spray coating thickness 0.12 mm;

[0014] After spraying, the coating tensile strength was measured to be 51MPa, the hardness was 78HR15N, and it reached a complete anti-oxidation level after being kept at 750℃ for 200h.

[0015] The preferred embodiment of the application method of the cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating is that in step three, the sand blowing pressure is 0.40 MPa, the sand blowing distance is 130 mm, and the sand blowing angle is 75°.

[0016] The preferred embodiment of the application method of the cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating is that in step 4, the temperature at which the parts are preheated is 80-100°C.

[0017] The preferred embodiment of the application method of the cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating is that the cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating is suitable for parts at a temperature below 750°C.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] The technical solution proposed by the present invention is to add nickel aluminum powder to cobalt chromium tungsten powder in a ratio of 1:1, and utilize the self-exothermic characteristics of nickel aluminum powder to improve the melting state of the powder, thereby improving the bonding strength between the coating and the substrate without reducing the hardness of the coating, and can improve the coating deposition efficiency. The coating is applied by automated plasma spraying, with low spraying cost and high efficiency. The coating can be used below 750°C and has good wear resistance, bonding strength, oxidation resistance and adhesion resistance.

[0020] The coating of this technical solution can not only be used for low-pressure guides of aircraft engines, but also for wear-resistant parts of high-temperature parts such as combustion chambers and flame tubes. It can meet the needs of high-temperature wear resistance and anti-adhesion on the surface of aircraft engine components, and can also be used for related parts in other industries, with high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the spraying part of the low-pressure guide;

[0022] Figure 2 for Figure 1 Middle I enlarged image.

[0023] In the figure: 1-Spraying area. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-2 The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings.

[0025] A method for preparing a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating and its application, comprising the following steps:

[0026] Step 1: Spread the cobalt-chromium-tungsten and nickel-aluminum powders on a covered tray respectively, and dry them in an oven set at 80°C for 1 hour. The dried powders are stored in an oven or other dry container before use. Before use, mix the two powders in a mass ratio of 1:1 and stir them thoroughly for 20 minutes to ensure the uniformity of the powders.

[0027] Step 2: Use absorbent cotton or a brush dipped in acetone to carefully wipe and clean the spray area 1 and adjacent areas of the part to thoroughly remove the oil stains on the surface of the part; blow dry with compressed air and wear clean gloves to touch the parts to avoid secondary contamination of the parts;

[0028] Step 3: Use tooling or pressure-sensitive tape to protect the non-spraying area. After confirming that the protection is effective, use a pressure-type sandblasting machine for sandblasting. The sandblasting air pressure is 0.40MPa, the sandblasting distance is 130mm, and the sandblasting angle is 75°. After sandblasting, use clean compressed air to blow away the floating dust on the surface of the parts after sandblasting.

[0029] Step 4: Use METCO 9MC plasma spray equipment to prepare the coating, and the spray gun is METCO 9MB type; use the spray gun to preheat the parts, and the preheating temperature is 80-100℃; the time interval between sandblasting and each coating spraying shall not exceed 2h, and the spraying area shall be cleaned with compressed air before each spraying;

[0030] Step 5: Spray coating, current is 500A, argon flow rate is 45L / min, hydrogen flow rate is 5.0L / min, powder feeding rate is 35g / min, spraying distance is 130mm; spray coating thickness is 0.12mm.

[0031] After spraying, the coating tensile strength was measured to be 51MPa, the hardness was 78HR15N, and the coating reached a complete anti-oxidation level after being kept at 750℃ for 200h.

[0032] Matters not covered by the present invention are known technologies.

[0033] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a cobalt-chromium-tungsten-nickel-aluminum high-temperature wear-resistant coating, characterized in that: The powder for preparing the coating is cobalt-chromium-tungsten powder and nickel-aluminum powder, and the two powders are mixed in a mass ratio of 1:1 to prepare a composite powder; The cobalt-chromium-tungsten powder has a Co content of 50-58%, a Cr content of 24.5-26.5%, a W content of 7.2-8.2%, a Ni content of 9.5-11.5%, a C content of 0.8-0.9%, a Mn and Si content of no more than 0.5%, a B content of no more than 0.01%, and a Fe content of no more than 2.0%; the particle size distribution is +105μm≤2%, -105μm~+45μm≥95%, -45μm≤3%; The nickel aluminum powder has a Ni content of 88-90%, an Al content of 8-11%, a free nickel content of less than 1%, and a total impurity content of less than 1%; the particle size distribution is +90 μm≤5%, -90 μm to +45 μm≥85%, and -45 μm≤10%.

2. The application method of a cobalt-chromium-tungsten-nickel-aluminum high temperature wear-resistant coating according to claim 1, characterized in that: The steps include: Step 1: Spread the cobalt-chromium-tungsten and nickel-aluminum powders on a covered tray respectively, and dry them in an oven set at 80°C for 1 hour. The dried powders are stored in an oven or other dry container before use. Before use, the cobalt-chromium-tungsten powder and the nickel-aluminum powder are mixed at a mass ratio of 1:1 to prepare the composite powder; stir thoroughly for 20 minutes to ensure the uniformity of the powder; Step 2: Use absorbent cotton or a brush dipped in acetone to carefully wipe and clean the spraying area and adjacent areas of the parts to thoroughly remove the oil stains on the surface of the parts; use compressed air to blow dry, and wear clean gloves to touch the parts to avoid secondary contamination of the parts; Step 3: Use special tooling or pressure-sensitive tape to protect the non-spraying area. After confirming that the protection is effective, use a pressure sandblasting machine to blow sand. After sandblasting, use clean compressed air to blow away the floating dust on the surface of the parts after sandblasting. Step 4: The coating is prepared by automated plasma spraying. The robot holds the spray gun, and the running program is linked with the spray equipment, which can be started with one button. The parts are preheated with the spray gun. The time interval between sand blowing and each coating spraying shall not exceed 2 hours. The spraying area shall be cleaned with compressed air before each spraying. Step 5: The spray coating process parameters are: argon flow rate 42.5~47.2L / min, hydrogen flow rate 4.7~6.1L / min, current 450~510A, powder feeding rate 30~45g / min, spraying distance 130~145mm, and spray coating thickness 0.12mm.

3. The application method of a cobalt-chromium-tungsten-nickel-aluminum high temperature wear-resistant coating according to claim 2, characterized in that: In step three, the sand blowing air pressure is 0.40 MPa, the sand blowing distance is 130 mm, and the sand blowing angle is 75°.

4. The application method of the cobalt-chromium-tungsten-nickel-aluminum high temperature wear-resistant coating according to claim 2 is characterized in that: In step 4, the temperature for preheating the parts is 80-100°C.

5. The application method of the cobalt-chromium-tungsten-nickel-aluminum high temperature wear-resistant coating according to claim 1, characterized in that: Cobalt-chromium-tungsten-nickel-aluminum high temperature wear-resistant coating is suitable for parts with temperatures below 750°C.

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