A composite coating structure on an aluminum alloy piece of a vacuum pump and a vacuum pump

Abstract

The application discloses a composite coating structure on an aluminum alloy part of a vacuum pump and the vacuum pump, and the composite coating structure comprises an aluminum alloy base body, an anodic oxidation film layer and a NiP-PTFE composite plating layer which are prepared on the aluminum alloy base body from inside to outside in sequence. The composite coating structure can effectively improve the corrosion resistance of the aluminum alloy part.

Description

Technical Field

[0001] The embodiments of this utility model relate to the field of metal electroplating technology. More specifically, this utility model relates to a composite coating structure on an aluminum alloy part of a vacuum pump and a vacuum pump. Background Technology

[0002] A vacuum pump is used to remove gas from a vacuum chamber to reduce the vacuum level to below standard atmospheric pressure. This type of equipment has been widely used in many industries, including semiconductors, photovoltaic solar energy, new energy batteries, and aerospace.

[0003] However, with continuous advancements in manufacturing processes, these industries often involve highly corrosive media. When handling these corrosive media, the aluminum alloy components in vacuum pumps that come into contact with the gas have limited corrosion resistance, failing to meet the requirements of more demanding corrosive environments. Over time, these components suffer severe corrosion, leading to reduced pumping efficiency and even malfunctions and shutdowns. In extreme cases, corrosion can even cause safety accidents, resulting in pump damage. This not only significantly shortens the service life of components but also causes substantial economic losses and extended production cycles for the industry, while increasing production safety risks. Therefore, these factors severely limit the application of vacuum pumps under more stringent process conditions. Utility Model Content

[0004] To address one or more of the technical problems mentioned above, this utility model provides a composite coating structure on an aluminum alloy part of a vacuum pump and a vacuum pump.

[0005] According to a first aspect of the present invention, a composite coating structure for an aluminum alloy component of a vacuum pump is provided. The composite coating structure includes an aluminum alloy substrate, and an anodic oxide film and a NiP-PTFE composite coating sequentially formed from the inside to the outside on the aluminum alloy substrate.

[0006] In some embodiments, the thickness of the anodic oxide film ranges from 5 μm to 20 μm.

[0007] In some embodiments, the thickness of the anodic oxide film is 5 μm.

[0008] In some embodiments, the anodic oxide film layer includes an inner barrier layer and an outer porous layer, wherein the thickness of the inner barrier layer is less than the thickness of the outer porous layer.

[0009] In some embodiments, the thickness of the NiP-PTFE composite coating ranges from 5 μm to 40 μm.

[0010] In some embodiments, the thickness of the NiP-PTFE composite coating is 15 μm.

[0011] In some embodiments, the NiP-PTFE composite coating comprises a substrate formed of a nickel-phosphorus alloy and particles made of polytetrafluoroethylene embedded within the substrate.

[0012] According to a second aspect of the present invention, a vacuum pump is provided. The vacuum pump includes an aluminum alloy component and the aforementioned composite coating structure.

[0013] In some embodiments, a worm gear is also included, which is constructed of an aluminum alloy.

[0014] In some embodiments, the vacuum pump is a magnetically levitated molecular pump.

[0015] The composite coating structure described above has the following advantages:

[0016] (1) Since the anodic oxide film is derived from the oxidation of aluminum alloy substrate, the anodic oxide film layer and the NiP-PTFE composite coating layer have extremely strong bonding performance. Even in the face of complex working conditions, the composite coating structure of this utility model embodiment is not easy to crack, delaminate, or fall off.

[0017] (2) Because the NiP-PTFE composite coating has a sealing effect on the anodic oxide film, it solves the surface porosity of the anodic oxide film, making the anodic oxide film and the NiP-PTFE composite coating more dense. Moreover, both the anodic oxide film and the NiP-PTFE composite coating have excellent corrosion resistance, providing dual protection for the parts and giving them extremely strong corrosion resistance, making them more resistant to harsh processes.

[0018] (3) Due to the high hardness of NiP in the NiP-PTFE composite coating, with a hardness range of 400-600 HV, and the low coefficient of friction of PTFE in the NiP-PTFE composite coating (as low as 0.09), the anodic oxide film and the NiP-PTFE composite coating possess excellent wear-resistant and self-lubricating properties.

[0019] (4) Due to the high and low temperature resistance of the anodic oxide film and the NiP-PTFE composite coating, it can be used for a long time at -200~260℃ and can withstand up to 300℃.

[0020] (5) Due to the low surface energy of the PTFE layer in the NiP-PTFE composite coating, the anodic oxide film and the NiP-PTFE composite coating have anti-stick properties, which can effectively prevent powder and other process materials from being deposited on the protected parts.

[0021] (6) The composite coating structure of this utility model embodiment is non-toxic, environmentally friendly and safe, with uniform thickness, easy to prepare, and has no restrictions on the shape of the parts, which makes the protected equipment have lower maintenance costs, significantly reduces costs, saves parts materials, and has good social benefits and economic value. Attached Figure Description

[0022] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0023] Figure 1 This is a schematic diagram of the composite coating structure according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0025] Figure 1 A composite coating structure 100 on an aluminum alloy part of a vacuum pump according to an embodiment of the present invention is shown. For example... Figure 1 As shown, the composite coating structure 100 includes an aluminum alloy substrate 1, and an anodic oxide film layer 2 and a NiP-PTFE composite coating layer 3 sequentially formed from the inside to the outside on the aluminum alloy substrate 1.

[0026] The preparation process of the composite coating structure 100 according to an embodiment of the present invention is as follows:

[0027] Step 1: Perform pre-plating treatment on the aluminum alloy substrate 1.

[0028] Detailed preparation process: The aluminum alloy substrate 1 is subjected to degreasing and cleaning, alkaline etching, chemical polishing, and nitric acid immersion to remove the black film in sequence. After each step, it is washed with ultrapure water and finally dried for later use.

[0029] Step 2: Anodize the aluminum alloy substrate 1 after pre-plating treatment to form an oxide film.

[0030] Detailed manufacturing process: The pre-treated aluminum alloy substrate 1 is placed in a special electrolyte solution, and an electric current is passed through it to form an anodic oxide film on the surface of the aluminum alloy substrate 1. After anodizing, a sealing process is performed, and finally, the parts are promptly cleaned with ultrapure water and dried.

[0031] Step 3: After the anodizing in step 2, promptly electrolessly deposit a NiP-PTFE composite coating 3.

[0032] Detailed preparation process: The aluminum alloy substrate 1, which has undergone anodizing in step 2, is placed in a chemical plating tank containing a special chemical plating solution. A NiP-PTFE composite coating 3 is deposited on the surface of the parts through a chemical reaction. After the chemical plating is completed, the parts are promptly cleaned with deionized water and dried.

[0033] Step 4, post-plating treatment.

[0034] The aluminum alloy substrate 1 with the chemically plated NiP-PTFE composite coating 3 prepared in step 3 is placed in a heat treatment furnace for annealing heat treatment. After the heat treatment is completed, the parts are promptly cleaned with deionized water and dried.

[0035] After the above steps, an anodized film layer 2 and a NiP-PTFE composite coating layer 3 are formed from the inside to the outside on the aluminum alloy substrate 1. Thus, when the composite coating structure 100 according to this embodiment of the invention is applied to aluminum alloy parts of a vacuum pump, it has the following advantages:

[0036] (1) Since the anodic oxide film is derived from the oxidation of aluminum alloy substrate, the anodic oxide film layer 2 and the NiP-PTFE composite coating layer 3 have extremely strong bonding performance. Even in the face of complex working conditions, the composite coating structure 100 of this utility model embodiment is not easy to crack, delaminate or fall off.

[0037] (2) Since the NiP-PTFE composite coating 3 has a sealing effect on the anodic oxide film 2, it solves the surface pores of the anodic oxide film 2, making the anodic oxide film 2 and the NiP-PTFE composite coating 3 more compact. Moreover, both the anodic oxide film 2 and the NiP-PTFE composite coating 3 have excellent corrosion resistance, providing dual protection for the parts, giving them extremely strong corrosion resistance and making them more resistant to harsh processes.

[0038] (3) Due to the high hardness of NiP in the NiP-PTFE composite coating 3, with a hardness range of 400-600 HV, and the low coefficient of friction of PTFE in the NiP-PTFE composite coating 3 (as low as 0.09), the anodic oxide film 2 and the NiP-PTFE composite coating 3 possess excellent wear-resistant and self-lubricating properties.

[0039] (4) Because the anodic oxide film layer 2 and the NiP-PTFE composite coating layer 3 are resistant to high and low temperatures, they can be used for a long time at -200 to 260℃ and can withstand up to 300℃.

[0040] (5) Due to the low surface energy of the PTFE layer in the NiP-PTFE composite coating 3, the anodic oxide film layer 2 and the NiP-PTFE composite coating 3 have anti-stick properties, which can effectively prevent powder and other process materials from being deposited on the protected parts.

[0041] (6) The composite coating structure of this utility model embodiment is 100% non-toxic, environmentally friendly and safe, with uniform thickness, easy to prepare, and no restrictions on the shape of the parts, which makes the protected equipment have lower maintenance costs, significantly reduces costs, saves parts materials, and has good social benefits and economic value.

[0042] In some embodiments, the thickness of the anodic oxide film 2 ranges from 5 μm to 20 μm. Preferably, the thickness of the anodic oxide film 2 is 5 μm.

[0043] In some embodiments, the anodic oxide film layer 2 includes an inner barrier layer and an outer porous layer, wherein the thickness of the inner barrier layer is less than the thickness of the outer porous layer.

[0044] In this application, the process conditions for anodizing the aluminum alloy substrate 1 include:

[0045] In the specially formulated electrolyte solution, sulfuric acid 100–500 g / L, organic acid 10–60 g / L, pH 3–6, temperature -10–20 °C; the current method uses pulsed current, constant DC, or constant DC plus pulsed current, with a current density of 0.5–10 A / dm³. 2 During the sealing process, pure water, nickel acetate, or potassium dichromate are used for sealing. The sealing temperature is 70–100℃, and the sealing time is 20–120 min. The thickness of the anodic oxide film layer 2 is 5–20 μm.

[0046] Optimal process conditions: In the specially prepared electrolyte solution, sulfuric acid 250g / L, organic acid 20g / L, pH 4, temperature -5℃; constant DC current mode, current density 0.5~10A / dm2; in the sealing process, pure water is used for sealing, sealing temperature 95℃, sealing time 60min; the thickness of the anodic oxide film layer 2 is 5μm.

[0047] In some embodiments, the thickness of the NiP-PTFE composite coating 3 ranges from 5 μm to 40 μm. Preferably, the thickness of the NiP-PTFE composite coating 3 is 15 μm.

[0048] In some embodiments, the NiP-PTFE composite coating 3 includes a substrate formed of a nickel-phosphorus alloy and particles made of polytetrafluoroethylene embedded in the substrate.

[0049] In this application, the process conditions for electroless plating of a NiP-PTFE layer after anodizing in step 2 include:

[0050] In the specially formulated chemical plating solution, nickel sulfate is 10–40 g / L, sodium hypophosphite is 1–40 g / L, and the complexing agents are: lactic acid 10–50 g / L (main complexing agent), sodium glycolate 10–55 g / L (auxiliary complexing agent), citric acid 5–40 g / L (auxiliary complexing agent), and succinic acid 2–20 g / L (auxiliary complexing agent); the stabilizers are: sodium thiosulfate 0.05–20 g / L and potassium iodide 0.05–20 g / L. Thiourea 0.1–20 ppm, ammonium fluoride 0.05–10 g / L, sodium acetate 5–40 g / L (buffer), propionic acid 1–30 mL / L (accelerator), PTFE emulsion 10–100 mL / L (PTFE solid content in PTFE emulsion 5–60%) and water, pH 3.5–6.5, temperature 40–100 °C; the thickness of NiP-PTFE composite coating 3 is 5–40 μm.

[0051] Optimal process conditions: In the specially prepared chemical plating solution, nickel sulfate 20-25 g / L, sodium hypophosphite 30-35 g / L, complexing agents: lactic acid 25 g / L (main complexing agent), sodium glycolate 30 g / L (auxiliary complexing agent), citric acid 15 g / L (auxiliary complexing agent), succinic acid 5-10 g / L (auxiliary complexing agent), stabilizers: sodium thiosulfate 0.4 g / L, potassium iodide 0.1 g / L, thiourea 1-3 ppm, ammonium hydrogen fluoride 0.3-0.5 g / L, sodium acetate 18 g / L (buffer), propionic acid 7 mL / L (accelerator), PTFE emulsion 40 mL / L (PTFE solid content in the PTFE emulsion is 30%) and water, pH value 5, temperature 90℃; the thickness of NiP-PTFE composite coating 3 is 15 μm.

[0052] It should be added that:

[0053] In this application, the process conditions for pre-plating treatment of the aluminum alloy substrate 1 include:

[0054] Degreasing and cleaning involves immersion in an organic solvent formed by mixing acetone and anhydrous alcohol in different proportions for 1–20 minutes; alkaline etching involves immersion in a 20–200 g / L NaOH solution for 10–40 seconds at a temperature of 30–70°C; chemical polishing involves immersion in a solution formed by mixing 30–70% (mass fraction) phosphoric acid, 5–20% (mass fraction) nitric acid, and 5–30% (mass fraction) sulfuric acid for 1–10 minutes at a temperature of 50–100°C; nitric acid immersion to remove the black film involves immersion in a 5–30% (mass fraction) nitric acid solution for 5–30 minutes at a temperature of 15–45°C; and ultrapure water rinsing takes 10–120 seconds each time.

[0055] Optimal process conditions: Degreasing and cleaning involves immersion in an organic solvent formed by mixing acetone and anhydrous alcohol in a 4:1 ratio for 5 minutes; Alkaline etching involves immersion in a 100 g / L NaOH solution for 20 seconds at 40°C; Chemical polishing involves immersion in a solution formed by mixing 60% (mass fraction) phosphoric acid, 5% (mass fraction) nitric acid, and 10% (mass fraction) sulfuric acid for 2 minutes at 90°C; Nitric acid immersion to remove the black film involves immersion in a 15% (mass fraction) nitric acid solution for 20 minutes at 25°C; Each ultrapure water cleaning session lasts 30 seconds.

[0056] In this application, the detailed preparation process for the post-plating treatment includes:

[0057] The annealing heat treatment process involves holding the temperature at 100–200℃ for 1–5 hours, followed by cooling in the furnace to room temperature before removal.

[0058] Optimal process conditions: The annealing heat treatment process involves holding at 150℃ for 2 hours and then cooling in the furnace to room temperature before removal.

[0059] According to a second aspect of the present invention, a vacuum pump is provided. The vacuum pump includes an aluminum alloy component and the aforementioned composite coating structure 100.

[0060] In some embodiments, a worm gear is also included, which is constructed of an aluminum alloy.

[0061] In this application, the aluminum alloy parts, in addition to the worm gear, can also be other aluminum alloy parts, which are aluminum alloy parts that require improved strength and corrosion resistance.

[0062] In some embodiments, the vacuum pump may be a magnetically levitated molecular pump.

[0063] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0064] Based on the above description of this application, those skilled in the art will also understand that the following terms used, such as "upper," "lower," "front," "rear," "left," "right," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "center," "longitudinal," "transverse," "clockwise," or "counterclockwise," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this application. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as a limitation on the present invention.

[0065] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0066] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A composite coating structure on an aluminum alloy part of a vacuum pump, characterized in that, It includes an aluminum alloy substrate, and an anodic oxide film and a NiP-PTFE composite coating formed sequentially from the inside to the outside on the aluminum alloy substrate.

2. The composite coating structure according to claim 1, characterized in that, The thickness of the anodic oxide film ranges from 5 μm to 20 μm.

3. The composite coating structure according to claim 2, characterized in that, The thickness of the anodic oxide film is 5 μm.

4. The composite coating structure according to any one of claims 1-3, characterized in that, The anodic oxide film layer includes an inner barrier layer and an outer porous layer, wherein the thickness of the inner barrier layer is less than the thickness of the outer porous layer.

5. The composite coating structure according to claim 1, characterized in that, The thickness of the NiP-PTFE composite coating ranges from 5 μm to 40 μm.

6. The composite coating structure according to claim 5, characterized in that, The thickness of the NiP-PTFE composite coating is 15 μm.

7. The composite coating structure according to any one of claims 1, 5, and 6, characterized in that, The NiP-PTFE composite coating comprises a substrate formed of a nickel-phosphorus alloy and particles made of polytetrafluoroethylene embedded within the substrate.

8. A vacuum pump, characterized in that, It includes aluminum alloy parts and composite coating structures according to any one of claims 1-7.

9. The vacuum pump according to claim 8, characterized in that, It also includes a worm gear, which is constructed from the aluminum alloy component.

10. The vacuum pump according to claim 8, characterized in that, The vacuum pump is a magnetically levitated molecular pump.

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