A method for preparing a wear-resistant lubricating film layer for aviation shaft parts

Abstract

The present invention discloses a method for preparing a wear-resistant lubricating film layer for aviation shaft parts, the method comprising the following steps: finishing the surface of the aviation shaft parts; cleaning oil stains on the surface of the parts; shielding the surface of the parts where no film layer needs to be deposited using a protective tool; hanging the parts on the furnace of a vacuum coating device; preparing a metal adhesion layer of NiCr, Cr, and W on the surface of a landing gear using magnetron sputtering; preparing a diamond-like film layer on the metal adhesion layer using acetylene using a plasma-enhanced chemical vapor deposition method; removing the protective tool and testing the film layer for quality. The diamond-like film layer of the present invention has a gradient transition structure of NiCr, a NiCr / Cr mixed layer, a Cr / W mixed layer, a W / Cr mixed layer, and a DLC functional layer. The prepared diamond-like film layer is uniform and dense, has excellent wear resistance, and has high process controllability. The film layer has a thickness of 3μm to 6μm, a hardness of HV2000 or above, and a friction coefficient of less than 0.2, meeting the use requirements of wear-resistant and lubricating shaft parts.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation parts processing, and in particular relates to a method for preparing a wear-resistant lubricating film layer of aviation shaft parts. Background Art

[0002] During use, aviation shaft parts are subject to heavy load rotation and vibration, which can lead to sliding wear, fretting wear, and pitting wear, causing component seizure and reducing part reliability and service life. Therefore, it is necessary to prepare a coating with high hardness, low friction coefficient, high bonding strength, and good chemical stability for aviation shaft parts to improve wear resistance and increase service life.

[0003] Shaft parts require high assembly precision, and the cost of replacing or repairing them after wear is high. The current wear protection method for aviation shaft parts is hard chrome electroplating. This process uses a large amount of hexavalent chromium, which is highly toxic and polluting. The hard chrome layer contains numerous microcracks, which affect the sealing of parts requiring sealing. The hard chrome layer has high internal stress, which significantly reduces the fatigue strength of the parts. The electroplated hard chrome layer has poor uniformity, requiring a thickness of at least 25 microns, which significantly affects part assembly. Post-plating grinding is often used to ensure part precision and roughness, which increases process cycle time and poses the risk of chromium chipping.

[0004] Based on the above problems, aviation shaft parts are in urgent need of a high-quality, efficient and environmentally friendly new process to replace electroplated hard chromium and solve the lubrication, wear and sealing problems of shaft parts. In recent years, with the development of manufacturing technology, high-hardness hard film layers have shined in the manufacturing field, such as TiN, CrN, CrAlN, c-BN, etc. These hard films have great potential to replace electroplated hard chromium, but their application in aviation shafts has problems such as too high process temperature, low film bonding strength, high friction coefficient, and poor corrosion resistance. Diamond-like carbon film is mainly composed of diamond-structured SP 3 Hybridized carbon atoms and sp 2 It is composed of carbon atoms and has the advantages of high hardness, low friction coefficient, acid and alkali resistance. It is an ideal friction and wear protection material. Summary of the Invention

[0005] To overcome these shortcomings, the inventors of this invention, through long-term exploration, numerous experiments, and continuous innovation, have developed a wear-resistant lubricating film for aviation shaft parts and a method for its preparation. Through structural and process control, the film's adhesion is improved, the process temperature is reduced, and the application requirements of aviation shaft parts are met. The wear-resistant lubricating film for aviation shaft parts comprises a NiCr layer, a NiCr / Cr mixed layer, a Cr / W mixed layer, a W / Cr mixed layer, and a DLC functional layer (diamond-like carbon functional layer). A layer-by-layer, gradual transition is achieved from the metal substrate to the DLC functional layer, balancing the performance differences between the different layers. The resulting wear-resistant lubricating film exhibits a uniform and dense structure, good adhesion to the substrate, low process temperature, and excellent wear resistance and friction reduction. This process is highly controllable, with a total film thickness of 3 to 6 μm, a hardness exceeding HV2000, and a coefficient of friction below 0.2.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a method for preparing a wear-resistant lubricating film layer for aviation shaft parts. The steps include:

[0007] a. Finish the surface of aviation shaft parts;

[0008] b. Clean the oil stains on the surface of parts;

[0009] c. Determine the area where the diamond-like carbon film needs to be prepared, and use protective tooling to shield the surface of the parts that do not need to deposit the film;

[0010] d. Fix the parts in the vacuum coating chamber with the area to be coated facing the magnetron sputtering target, connect the landing gear to the negative pole of the bias power supply, and connect the vacuum coating chamber to the positive pole of the power supply;

[0011] e. Turn on the argon plasma cleaning source and perform argon plasma etching and cleaning on the landing gear surface for a cleaning time of not less than 0.5 hours;

[0012] f. Using magnetron sputtering to prepare a metal adhesion layer of NiCr, Cr, and W on the landing gear surface;

[0013] g. preparing a diamond-like carbon film on the metal adhesion layer using a plasma enhanced chemical vapor deposition method;

[0014] h. Remove the protective tooling on the surface of the parts and conduct a qualification test on the film layer.

[0015] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts of the present invention, a further preferred technical solution is: before step a, the surface condition of the parts is checked, and finishing is performed only after there are no bumps or scratches.

[0016] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts of the present invention, a further preferred technical solution is: in step a, finishing must make the surface roughness of the part less than Ra0.2μm.

[0017] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts described in the present invention, a further preferred technical solution is: in step b, the parts are ultrasonically cleaned with anhydrous ethanol and acetone, and no traces of rust are found after cleaning. After the parts are moistened with deionized water, the water film is checked to be continuous for 30 seconds. If there is no water film rupture, it is qualified. After passing the inspection, the parts are blown dry in time to check whether there is rust on the parts. If unqualified, the cleaning process is repeated.

[0018] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts described in the present invention, a further preferred technical solution is: in step f, by controlling the sputtering power of NiCr, Cr, and W, the prepared metal adhesion layer has the organizational structure of NiCr, NiCr / Cr mixed layer, and Cr / W mixed layer; in step g, by controlling the sputtering power and gas flow of W, the prepared diamond-like film layer has the organizational structure of W / C mixed layer and diamond-like functional layer.

[0019] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts of the present invention, a further preferred technical solution is: in step f, the specific operation is: first, turn on the NiCr target sputtering power supply, the current is 40~70A / m 2 , deposit NiCr layer, bias voltage -50V~-200V; turn on Cr target sputtering power supply, Cr target current 120~170A / m 2 , forming a NiCr / Cr mixed layer; turn off the NiCr target, turn on the W target sputtering power supply, and the W target current is 100~130 A / m 2 , forming a Cr / W mixed layer.

[0020] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts described in the present invention, its further preferred technical solution is: in step g, the specific operations are: turning off the Cr target, introducing a carbon-containing gas source, and gradually increasing the flow rate to 500 sccm; gradually reducing the W target power until it is turned off, and gradually increasing the bias voltage to -500V~-700V, and preparing the DLC functional layer by plasma enhanced chemical vapor deposition.

[0021] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts described in the present invention, a further preferred technical solution is: in step g, the carbon-containing gas source is one or a mixture of methane, ethane, ethylene or acetylene.

[0022] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts of the present invention, a further preferred technical solution is that the thickness of the diamond-like film layer is not less than 2 microns.

[0023] According to the method for preparing a wear-resistant lubricating film layer for aviation shaft parts described in the present invention, a further preferred technical solution is: the protective tooling is shielded by aluminum foil, protective tape or a dedicated protective device.

[0024] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits:

[0025] 1. By combining magnetron sputtering and plasma-enhanced chemical vapor deposition, the wear-resistant lubricating film produced has a uniform and dense structure, good adhesion to the substrate, low processing temperature, and excellent wear resistance and friction reduction properties. This process is highly controllable, and the total film thickness is 3μm to 6μm, with a hardness exceeding HV2000 and a friction coefficient below 0.2.

[0026] 2. The film structure features a gradient transition layer structure of NiCr / NiCr-Cr / Cr-W / WC / DLC. The number of gradient transition layers is increased to alleviate interfacial stress. The sputtering current gradient is regulated to achieve a gradual transition between transition layers, increasing interfacial bonding strength. The DLC film achieves a level 1 indentation bonding strength, making it less likely to peel during service.

[0027] 3. The process temperature used in the present invention is lower than 2000°C, which will not have an adverse effect on the tensile properties and fatigue properties of the substrate.

[0028] 4. After the processing of the present invention is completed, the film layer is dense and does not require additional sealing steps to meet the sealing requirements.

[0029] 5. The total thickness of the film layer is 3μm to 6μm, which has no effect on the dimensional accuracy of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 The present invention is a flow chart of a method for preparing a wear-resistant lubricating film layer for aviation shaft parts.

[0032] Figure 2These are the micromorphologies of electroplated hard chromium and DLC film layers, where a) and c) are electroplated hard chromium, and b) and d) are DLC film layers.

[0033] Figure 3 It is a film layer structure diagram of a method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it may not be further defined or explained in subsequent drawings.

[0036] Example 1:

[0037] like Figure 1 As shown, a method for preparing a wear-resistant lubricating film layer for aviation shaft parts. The steps include:

[0038] a. Finish the surface of aviation shaft parts. The surface roughness of the parts must be less than Ra0.2μm.

[0039] b. Clean the oil stains on the surface of the parts, use anhydrous ethanol and acetone to ultrasonically clean the parts. After cleaning, there should be no signs of rust. Use deionized water to wet the parts and check if the water film is continuous for 30 seconds. If there is no water film breakage, it is qualified. After passing the inspection, blow dry in time and check if the parts are free of rust. If unqualified, repeat the cleaning process until the standard is met;

[0040] c. Determine the area where the diamond-like carbon film needs to be deposited, and use protective tooling to mask the surface of the parts where the film does not need to be deposited. Protective tooling is a general term and can take many forms. For example, protective tooling can be achieved by using aluminum foil, protective tape, or a dedicated protective device to achieve masking;

[0041] d. Fix the parts in the vacuum coating chamber with the area to be coated facing the magnetron sputtering target, connect the landing gear to the negative pole of the bias power supply, and connect the vacuum coating chamber to the positive pole of the power supply;

[0042] e. Turn on the argon plasma cleaning source and perform argon plasma etching and cleaning on the landing gear surface. The cleaning time should be no less than 0.5 hours. Of course, the cleaning time can be flexibly set according to needs and can also be less than 0.5 hours;

[0043] f. Using magnetron sputtering to prepare a metal adhesion layer of NiCr, Cr, and W on the landing gear surface;

[0044] g. preparing a diamond-like carbon film on the metal adhesion layer using a plasma enhanced chemical vapor deposition method;

[0045] h. After the preset film thickness is reached, turn off the anode layer ion source and bias power supply. After the temperature in the chamber drops below 80°C, open the furnace door, take out the landing gear, remove the protective tooling on the surface of the part, and conduct a qualification test on the film layer. The thickness of the diamond-like carbon film layer is required to be no less than 2 microns.

[0046] At the same time, before step a, it is necessary to check the surface condition of the parts and confirm that there are no bumps or scratches before finishing.

[0047] In step f, by controlling the sputtering power of NiCr, Cr, and W, the prepared metal adhesion layer has the organizational structure of NiCr, NiCr / Cr mixed layer, and Cr / W mixed layer. The specific operation is as follows: first, turn on the NiCr target sputtering power supply, the current is 40~70A / m2, and the NiCr layer is deposited with a bias voltage of -50V~-200V; turn on the Cr target sputtering power supply, the Cr target current is 120~170A / m2, and the NiCr / Cr mixed layer is formed; turn off the NiCr target, turn on the W target sputtering power supply, the W target current is 100~130A / m2, and the NiCr / Cr mixed layer is formed; m2, forming a Cr / W mixed layer. In step g, by controlling the W sputtering power and gas flow, the deposited diamond-like carbon film has a microstructure of a W / C mixed layer and a DLC functional layer (diamond-like functional layer). The specific operation is as follows: turning off the Cr target, introducing a carbon-containing source gas, and gradually increasing the flow rate to 500 sccm; gradually reducing the W target power until it is turned off, and gradually increasing the bias voltage to -500V to -700V to deposit the DLC functional layer via plasma-enhanced chemical vapor deposition. In step g, the carbon-containing source gas introduced is one or a mixture of methane, ethane, ethylene, or acetylene. Of course, other gases that can achieve the same effect can also be used. Figure 2 This is a comparison between the hard chromium layer with a large number of microcracks and the DLC film layer.

[0048] Example 2:

[0049] Based on Example 1, the coating parameters are further illustrated in detail. In step f, the NiCr target sputtering power supply is first turned on with a current of 60 A / m 2, deposit NiCr layer, deposition time 40min, bias voltage -100V; turn on Cr target sputtering power, Cr target current 140 A / m 2 , forming a NiCr / Cr mixed layer, the deposition time is 50min; turn off the NiCr target, turn on the W target sputtering power supply, the W target current is 110 A / m 2 , forming a Cr / W mixed layer, the deposition time is 30min.

[0050] In step g, acetylene gas was introduced with the flow rate gradually increased from 50 sccm to 200 sccm, the Cr target was turned off, and the W target current was gradually reduced to zero to form a W / C mixed layer for 30 min. The W target was turned off, the acetylene flow rate was increased from 200 sccm to 600 sccm, and the bias voltage was increased from -100 V to -600 V to prepare a DLC functional layer by plasma-enhanced chemical vapor deposition for 500 min.

[0051] Working principle: Use magnetron sputtering and discharge plasma enhanced chemical vapor deposition method. Magnetron sputtering refers to the use of glow plasma discharge to ionize argon gas to produce argon ions, while applying a negative bias to the target material (NiCr, Cr, W target material). Under the magnetic field constraint of the equipment, argon ions are accelerated in the electric field and continuously sputter the target material, sputtering target atoms out of the target surface. Some target atoms collide with the argon ions and are ionized. The target atoms and ions reach the workpiece surface through the combined action of thermal motion and the negative bias applied to the part. By controlling the power of the target power supply, the thickness of the metal adhesion layer is controlled, and the metal adhesion layer is deposited. Plasma enhanced chemical vapor deposition refers to applying a high negative bias to the part to cause acetylene to glow discharge on the surface of the part. Acetylene is ionized into C-containing ions, which are deposited as a DLC functional layer on the surface of the part. The final film structure is as follows Figure 3 shown.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0053] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0054] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a wear-resistant lubricating film layer for aviation shaft parts, characterized in that: The steps include: a. polishing the surface of aviation shaft parts; b. cleaning the oil stains on the surface of the parts; c. determining the area where the diamond-like film layer needs to be prepared, and using protective tooling to shield the surface of the parts that do not need to deposit the film layer; d. fixing the parts in a vacuum coating chamber with the area to be coated facing the magnetron sputtering target, connecting the landing gear to the negative pole of the bias power supply, and connecting the vacuum coating chamber to the positive pole of the power supply; e. turning on the argon plasma cleaning source, and performing argon plasma etching and cleaning on the surface of the landing gear for a cleaning time of not less than 0.5h; f. using magnetron sputtering to prepare a metal adhesion layer of NiCr, Cr, and W on the surface of the landing gear, and by controlling the sputtering power of NiCr, Cr, and W, the prepared metal adhesion layer has the organizational structure of NiCr, NiCr / Cr mixed layer, and Cr / W mixed layer; g. using a plasma-enhanced chemical vapor deposition method to prepare a DLC functional layer on the metal adhesion layer, and by controlling the sputtering power and gas flow of W, the prepared diamond-like film layer has the organizational structure of W / C mixed layer and diamond-like functional layer; h. Remove the protective tooling on the surface of the parts and conduct a qualification test on the film layer.

2. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 1, characterized in that: Before step a, check the surface condition of the parts and make sure there are no bumps or scratches before finishing.

3. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 1, characterized in that: In step a, finishing must make the surface roughness of the part less than Ra0.2μm.

4. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 1, characterized in that: In step b, use anhydrous ethanol and acetone to ultrasonically clean the parts. After cleaning, there is no trace of rust. After wetting the parts with deionized water, check whether the water film is continuous for 30 seconds. If there is no water film rupture, it is qualified. After passing the inspection, blow dry in time and check whether the parts are free of rust. If unqualified, perform the cleaning process again.

5. A method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to any one of claims 1 to 4, characterized in that: In step f, the specific operation is as follows: first, turn on the NiCr target sputtering power supply, the current is 40~70A / m 2 , deposit NiCr layer, bias voltage -50V~-200V; turn on Cr target sputtering power supply, Cr target current 120~170A / m 2 , forming a NiCr / Cr mixed layer; turn off the NiCr target, turn on the W target sputtering power supply, and the W target current is 100~130 A / m 2 , forming a Cr / W mixed layer.

6. A method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to any one of claims 1 to 5, characterized in that: In step g, the specific operations are as follows: turn off the Cr target, introduce a carbon-containing gas source, and gradually increase the flow rate to 500 sccm; gradually reduce the W target power until it is turned off, and gradually increase the bias voltage to -500V~-700V to prepare the DLC functional layer by plasma enhanced chemical vapor deposition.

7. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 6, characterized in that: In step g, the carbon-containing gas source introduced is one or a mixture of any of methane, ethane, ethylene or acetylene.

8. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 6, characterized in that: The thickness of the DLC functional layer is not less than 2 microns.

9. The method for preparing a wear-resistant lubricating film layer for aviation shaft parts according to claim 1, characterized in that: The protective tooling is implemented by using aluminum foil and protective tape to achieve shielding.

Images