Tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing

Abstract

The invention relates to the technical field of bushings, and specifically discloses a tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing, the process comprising inspection, chemical cleaning pretreatment, chemical cleaning, lubricating layer preparation, interface elimination and inspection procedures; the invention adopts an interface elimination process, and uses a strong pulse beam to bombard the lubricating layer on the surface of a metal bushing substrate, so that the hierarchical interface between the metal bushing substrate surface and the lubricating layer is eliminated, and the bonding degree between the lubricating layer and the metal bushing substrate surface is improved, thereby reducing the risk of the high-load anti-friction lubricating layer falling off under extreme conditions; a lubricating layer is formed on the surface of the metal bushing substrate through physical meteorological deposition, so that the tungsten carbide coating attached to the surface of the metal bushing substrate has higher isotropic stability, and the stress corrosion resistance of the entire high-load anti-friction lubricating layer in extreme working environments is improved, thereby increasing the service life of the entire bushing.

Description

Technical Field

[0001] The invention relates to the technical field of bushings, and in particular to a tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing. Background Art

[0002] The self-lubricating bushing mainly plays a role of sealing, supporting and wearing protection between the movement of the shaft and the hole. In the application of aviation equipment, the requirements for self-lubricating bushings are higher, and the bushings are required to have high wear resistance, high lubricity and lightness. The self-lubricating bushings in the prior art include copper alloy bushings and tungsten carbide coated bushings. The strength of the copper alloy bushing is lower than that of the tungsten carbide coated bushing, while the tungsten carbide coated bushing has higher strength. For example, a wear-resistant bushing of a rocker arm of a coal mining machine disclosed in patent number CN221647423U includes a bushing substrate, and the inner hole surface of the bushing substrate is provided with a tungsten carbide cobalt-chromium coating. The bushing has high hardness, good wear resistance and a long service life, so it can meet general use requirements, but it still has the following disadvantages in actual use:

[0003] 1. In the prior art, there is a bonding interface between the bushing substrate and the tungsten carbide coating. However, in the extremely high temperature and high pressure environment encountered during the use of aviation equipment, the tungsten carbide coating has a great risk of falling off from the bushing substrate due to the existence of the bonding interface. Therefore, the bonding degree between the tungsten carbide and the tungsten carbide coating needs to be further improved;

[0004] 2. In the prior art, the tungsten carbide coated bushing is attached to the surface of the bushing substrate by thermal spraying, so the stability of the coating in all directions is not uniform enough. Therefore, under severe vibration, high temperature and high pressure, fatigue points are easily generated due to insufficient stability on the surface, which makes the coating easily eroded by stress, reducing the service life of the bushing in extreme environments. Therefore, the stability of the coating surface needs to be further improved. Summary of the invention

[0005] The purpose of the present invention is to provide a tungsten carbide coating and interface vanishing process for a high-load self-lubricating bushing to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing, wherein the high-load self-lubricating bushing specifically comprises a metal bushing substrate and a high-load anti-friction lubricating layer arranged in the metal bushing substrate, the metal bushing substrate is a cylindrical structure, and the high-load anti-friction lubricating layer is attached to the inner surface of the metal bushing substrate.

[0007] The process of the tungsten carbide coating and interface disappearance process of the high-load self-lubricating bushing specifically includes the following steps:

[0008] Step 1: Check the quality, material and surface condition of the metal bushing substrate, and determine the preparation materials required for subsequent processes based on the specific quality, material and surface condition of the metal bushing substrate;

[0009] Step 2: Chemical cleaning pretreatment, pre-treating the surface of the metal bushing substrate to remove the attached debris and dust on the surface;

[0010] Step 3: Chemical cleaning: using chemicals to pre-treat the surface of the metal bushing substrate to remove grease, oil and other impurities attached to the surface of the metal bushing substrate;

[0011] Step 4: preparing a lubricating layer, forming a lubricating layer on the surface of the metal bushing substrate by physical vapor deposition, and preparing a tungsten carbide coating on the surface of the metal bushing substrate by target sputtering technology, and the tungsten carbide coating is a lubricating layer on the surface of the metal bushing substrate;

[0012] Step 5: Eliminate the interface. Use high-energy beam atomic diffusion technology to bombard the lubricating layer on the surface of the metal bushing substrate with a strong pulse beam, so that the atomic particles of tungsten carbide in the lubricating layer are evenly diffused to the surface of the metal bushing substrate, so that the hierarchical interface between the surface of the metal bushing substrate and the lubricating layer is eliminated, so that a high-load-bearing and anti-friction lubricating layer attached to the surface of the metal bushing substrate is formed;

[0013] Step six: Inspection: The hardness, thickness and bonding strength of the high-load-bearing anti-friction lubrication layer attached to the surface of the metal bushing substrate are tested.

[0014] Preferably, in step 2, the specific pretreatment process is to put the metal bushing substrate into an ultrasonic cleaning tank, the cleaning tank is filled with clean water, the cleaning time is controlled at 3 min-5 min, and the water temperature is controlled at 20°C-40°C.

[0015] Preferably, in the step three, the metal bushing substrate is placed in an ultrasonic cleaning tank, the cleaning tank contains a well-proportioned chemical cleaning agent solution, the cleaning time is controlled at 20min-30min, the water temperature is controlled at 20℃-35℃, after the cleaning is completed, the metal bushing substrate is placed in an ultrasonic clean water tank for rinsing, the rinsing water temperature is controlled at 40℃-50℃, the rinsing time is controlled at 3min-5min, after the rinsing is completed, the metal bushing substrate is placed in a drying box, the moisture on the surface of the metal bushing substrate is dried, the drying temperature is controlled at 100℃, and the drying time is controlled at 50min-60min.

[0016] Preferably, in step 4, tungsten carbide is used as the sputtering target, and the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3Pa, the arc current is set to 70A-80A, the temperature is controlled at 450℃-500℃, the arc spot electromagnetic field intensity is medium, the arc source working mode is set to pulse, and the deposition time is controlled at 260min-300min.

[0017] Preferably, in step 5, the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3 Pa, the working voltage of the cathode ion source is controlled at 4KV, the working current is controlled at 150mA, and the working time is controlled at 30min-50min.

[0018] Compared with the prior art, the present invention has the following advantages: the present invention has a reasonable structure, strong functionality, and the following advantages:

[0019] 1. In the present invention, an interface elimination process is adopted, and a strong pulse beam is used to bombard the lubricating layer on the surface of the metal bushing substrate through high-energy beam atomic diffusion technology, so that the atomic particles of tungsten carbide in the lubricating layer are evenly diffused to the surface of the metal bushing substrate, so that the hierarchical interface between the surface of the metal bushing substrate and the lubricating layer is eliminated, and the bonding degree between the lubricating layer and the surface of the metal bushing substrate is improved, making the bonding more stable, so that the risk of falling off of the high-load-bearing anti-friction lubricating layer can be reduced under extreme conditions;

[0020] 2. In the present invention, a lubricating layer is formed on the surface of the metal bushing substrate by physical vapor deposition, so that the tungsten carbide coating attached to the surface of the metal bushing substrate has higher isotropic stability, and the stress corrosion resistance of the entire high-load-bearing anti-friction lubricating layer in extreme working environments is improved, thereby increasing the service life of the entire bushing;

[0021] 3. In the present invention, high-energy beam atomic diffusion technology is used to bombard the lubricating layer on the surface of the metal bushing substrate with a strong pulse beam, so that the atomic particles of tungsten carbide in the lubricating layer are evenly diffused to the surface of the metal bushing substrate, further improving the overall stability of the entire high-load-bearing and anti-friction lubricating layer, thereby further improving the service life of the entire bushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an axial side view of the overall structure of the high-load self-lubricating bushing in the present invention;

[0023] Figure 2 It is an exploded view of the shaft side of the high load-bearing self-lubricating bushing of the present invention;

[0024] Figure 3 It is a schematic diagram of the process flow of the present invention;

[0025] Figure 4 Schematic diagram of the diffusion of atoms in the lubricating layer on the surface of a metal bushing substrate at room temperature caused by an intense pulse beam;

[0026] Figure 5 It is the distribution quantity of atoms in the lubricating layer at different depths from the surface of the metal bushing substrate.

[0027] In the figure: 1. Metal bushing substrate; 2. High load-bearing anti-friction lubricating layer. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figures 1 to 5 The present invention provides a technical solution: a tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing. The high-load self-lubricating bushing specifically includes a metal bushing substrate 1 and a high-load anti-friction lubricating layer 2 arranged in the metal bushing substrate 1. The metal bushing substrate 1 is a cylindrical structure, and the high-load anti-friction lubricating layer 2 is attached to the inner surface of the metal bushing substrate 1.

[0030] A tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing specifically includes the following steps:

[0031] Step 1: Check the quality, material and surface condition of the metal bushing substrate. According to the specific quality, material and surface condition of the metal bushing substrate, determine the preparation materials required for the subsequent process. For example, set the subsequent cleaning time and the proportion of cleaning materials according to the surface condition of the metal bushing. If the surface of the metal bushing is dirty, increase the cleaning time. If the surface is heavily oily, increase the proportion of chemical cleaning agents.

[0032] Step 2: Chemical cleaning pretreatment, pre-treating the surface of the metal bushing substrate to remove the attached debris and dust on the surface, such as ultrasonic cleaning, or plasma cleaning;

[0033] Step three, chemical cleaning, using chemicals to pre-treat the surface of the metal bushing substrate to remove grease and oily impurities attached to the surface of the metal bushing substrate. The specific operation is to mix the cleaning chemicals according to the grease attached to the surface of the metal bushing substrate and pour them into the pool, and heat the pool water to a certain temperature, the temperature is controlled at 25℃-50℃, soak the metal bushing substrate in the pool water, and then perform ultrasonic cleaning. After the cleaning is completed, the metal bushing is placed in a clean water pool for rinsing. After the rinsing is completed, the metal bushing is dried and transferred to the next process;

[0034] Step 4: Lubricating layer preparation: a lubricating layer is formed on the surface of the metal bushing substrate by physical vapor deposition, and a tungsten carbide coating is prepared on the surface of the metal bushing substrate by target sputtering technology. The tungsten carbide coating is a lubricating layer on the surface of the metal bushing substrate, wherein tungsten carbide is a sputtering target, and the entire coating process can be achieved by a multifunctional ion plating machine;

[0035] Step 5: Eliminate the interface, such as Figure 4 As shown, A is the metal bushing substrate, B is the lubricating layer, and between A and B is the gradient layer formed after bombardment. Through high-energy beam atomic diffusion technology, a strong pulse beam is used to bombard the lubricating layer on the surface of the metal bushing substrate, so that the atomic particles of tungsten carbide in the lubricating layer are evenly diffused to the surface of the metal bushing substrate, so that the hierarchical interface between the surface of the metal bushing substrate and the lubricating layer is eliminated, so that a high-load-bearing and friction-reducing lubricating layer attached to the surface of the metal bushing substrate is formed. The whole process can be realized by a multifunctional ion plating machine, which performs reverse bombardment on the lubricating layer on the surface of the metal bushing substrate, controls the energy of the ion beam, and makes the atoms in the lubricating layer diffuse to the surface of the metal bushing substrate at room temperature, thereby improving the isotropic stability of the atoms in the lubricating layer and eliminating the hierarchical interface between the surface of the metal bushing substrate and the lubricating layer. Figure 5 As shown, the upper left is the depth parameter from the metal bushing substrate, and the lower right is the number of atoms distributed per unit volume at different depths from the metal bushing substrate in the lubricating layer. It can be seen that after the bombardment, the atomic density of the surface layer in the lubricating layer is increased, the stability of its surface is improved, the surface stress erosion resistance of the entire high-load-bearing anti-friction lubricating layer is improved, and the service life of the entire bushing is improved;

[0036] Step six, inspection, the hardness, thickness and bonding strength of the high-load anti-friction lubrication layer attached to the surface of the metal bushing substrate are tested. After the interface elimination process is completed, routine inspections are carried out on batches of bushings, and the hardness, thickness and bonding strength of the high-load anti-friction lubrication layer on the surface of the metal bushing substrate are tested item by item.

[0037] Furthermore, in step two, the specific pretreatment process is to put the metal bushing substrate into an ultrasonic cleaning tank with clean water, the cleaning time is controlled at 3min-5min, the water temperature is controlled at 20℃-40℃, the cleaning time is controlled according to the surface condition of the metal bushing substrate, and the water temperature is controlled according to the working environment temperature. When the ambient temperature is low, the water temperature is appropriately increased to 40℃, and the water temperature is controlled at about 25℃ under normal working environment. When the surface of the metal bushing substrate is relatively clean, it is cleaned for 3min, and when the surface is dirty, the cleaning time is controlled to 5min.

[0038] Furthermore, in step three, the metal bushing substrate is placed in an ultrasonic cleaning tank, which contains a well-proportioned chemical cleaning agent solution. The cleaning time is controlled at 20min-30min, and the water temperature is controlled at 20℃-35℃. The cleaning time can be controlled according to the severity of the oil pollution on the surface of the metal bushing substrate, and the water temperature can be controlled according to the working environment temperature. If the oil pollution on the surface of the metal bushing substrate is more serious, the cleaning time is increased to 30min as much as possible. When the ambient temperature is low, the water temperature is controlled at 35℃. After cleaning, the metal bushing substrate is placed in an ultrasonic water cleaning tank. Rinse, the rinsing water temperature is controlled at 40℃-50℃, and the rinsing time is controlled at 3min-5min. Among them, rinsing can be performed in multiple times, each time is controlled at 1-2 minutes. After rinsing, the metal bushing substrate is placed in a drying box to dry the moisture on the surface of the metal bushing substrate. The drying temperature is controlled at 100℃, and the drying time is controlled at 50min-60min. The drying time is determined according to the size of the metal bushing substrate and the number of batches. If the metal bushing substrate is large in size and the number of batches is large, the drying time is increased to 60min.

[0039] Furthermore, in step 4, tungsten carbide is used as the sputtering target, and the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3 Pa, the arc current is set to 70A-80A, the temperature is controlled at 450℃-500℃, the arc spot electromagnetic field intensity is medium, the arc source working mode is set to pulse, and the deposition time is controlled at 260min-300min. The arc current can be set according to the coating thickness of the tungsten carbide coating. If the coating thickness is large, the arc current is reduced to 70A and the deposition time is increased to 300min. If the coating thickness is small, the arc current can be increased to 80A, and the deposition time is controlled at 260min. The larger the arc current, the larger the tungsten carbide particle size, and the smaller the arc current, the smaller and more uniform the tungsten carbide particles.

[0040] Furthermore, in step 5, the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3 Pa, the working voltage of the cathode ion source is controlled at 4KV, the working current is controlled at 150mA, and the working time is controlled at 30min-50min. The working time is controlled according to the thickness of the tungsten carbide coating. The thicker the thickness, the longer the working time. The work is divided into multiple times, and each working time is 10min, so that the surface of the tungsten carbide coating can be processed more densely and evenly.

[0041] In summary, the 2mm thick tungsten carbide coating prepared according to the present process has a surface hardness of 3200HV-4200HV, a surface friction coefficient of <0.06, and a dynamic load bearing capacity that meets the radial dynamic load requirement of ≥400MPa, that is, the swing requirement of ±30°. According to the GJB10850 test requirements, the wear amount is ≤0.11mm. Compared with ordinary tungsten carbide coated bushings, the present invention improves the performance of tungsten carbide coatings.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A tungsten carbide coating and interface disappearance process for a high-load self-lubricating bushing, characterized in that: The high-load self-lubricating bushing specifically comprises a metal bushing base (1) and a high-load anti-friction lubricating layer (2) arranged in the metal bushing base (1); the metal bushing base (1) is a cylindrical structure, and the high-load anti-friction lubricating layer (2) is attached to the inner surface of the metal bushing base (1). The process of the tungsten carbide coating and interface disappearance process of the high-load self-lubricating bushing specifically includes the following steps: Step 1: Check the quality, material and surface condition of the metal bushing substrate, and determine the preparation materials required for subsequent processes based on the specific quality, material and surface condition of the metal bushing substrate; Step 2: Chemical cleaning pretreatment, pre-treating the surface of the metal bushing substrate to remove the attached debris and dust on the surface; Step 3: Chemical cleaning: pre-treating the surface of the metal bushing substrate with chemicals to remove grease, oil and impurities attached to the surface of the metal bushing substrate; Step 4: preparing a lubricating layer, forming a lubricating layer on the surface of the metal bushing substrate by physical vapor deposition, and preparing a tungsten carbide coating on the surface of the metal bushing substrate by target sputtering technology, and the tungsten carbide coating is a lubricating layer on the surface of the metal bushing substrate; Step 5: Eliminate the interface. Use high-energy beam atomic diffusion technology to bombard the lubricating layer on the surface of the metal bushing substrate with a strong pulse beam, so that the atomic particles of tungsten carbide in the lubricating layer are evenly diffused to the surface of the metal bushing substrate, so that the hierarchical interface between the surface of the metal bushing substrate and the lubricating layer is eliminated, so that a high-load-bearing and anti-friction lubricating layer attached to the surface of the metal bushing substrate is formed; Step six: Inspection: the hardness, thickness and bonding strength of the high-load-bearing anti-friction lubricating layer attached to the surface of the metal bushing substrate are tested.

2. The tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing according to claim 1, characterized in that: In the step 2, the specific pretreatment process is to put the metal bushing substrate into an ultrasonic cleaning tank, the cleaning tank is filled with clean water, the cleaning time is controlled at 3 min-5 min, and the water temperature is controlled at 20°C-40°C.

3. The tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing according to claim 1, characterized in that: In the step three, the metal bushing substrate is placed in an ultrasonic cleaning tank, which contains a well-proportioned chemical cleaning solution. The cleaning time is controlled at 20min-30min, and the water temperature is controlled at 20℃-35℃. After cleaning, the metal bushing substrate is placed in an ultrasonic clean water tank for rinsing. The rinsing water temperature is controlled at 40℃-50℃, and the rinsing time is controlled at 3min-5min. After rinsing, the metal bushing substrate is placed in a drying box to dry the moisture on the surface of the metal bushing substrate. The drying temperature is controlled at 100℃, and the drying time is controlled at 50min-60min.

4. The tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing according to claim 1, characterized in that: In step 4, tungsten carbide is used as the sputtering target, and the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3 Pa, the arc current is set to 70A-80A, the temperature is controlled at 450℃-500℃, the arc spot electromagnetic field intensity is medium, the arc source working mode is set to pulse, and the deposition time is controlled at 260min-300min.

5. The tungsten carbide coating and interface disappearance process of a high-load self-lubricating bushing according to claim 1, characterized in that: In step 5, the initial vacuum degree of the vacuum coating machine is controlled to be 10 -3 Pa, the working voltage of the cathode ion source is controlled at 4KV, the working current is controlled at 150mA, and the working time is controlled at 30min-50min.

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