Composite coating for self-lubricating surface of base material of internal component and preparation method of composite coating

Abstract

The invention provides an internal component base material surface self-lubricating composite coating which covers the surface of an internal component base material and comprises a toughening layer and a lubricating layer on the surface of the toughening layer, the toughening layer is prepared from a titanium-rare earth mixture, the lubricating layer is prepared from polytetrafluoroethylene and Ti3SiC2, and the thickness of the toughening layer accounts for 70%-95% of the thickness of the composite coating. The invention also provides a preparation method of the composite coating. The preparation method comprises the following steps: S1, cleaning the surface of an internal component base material to be subjected to surface treatment to remove surface impurities; s2, a titanium-rare earth mixture is deposited on the surface of the inner component base material subjected to ultrasonic cleaning to form a toughening layer; and S3, polytetrafluoroethylene and Ti3SiC2 are continuously deposited on the surface, where the toughening layer is formed, of the inner component base material to form a lubricating layer, and the self-lubricating composite coating is obtained. The composite coating provided by the invention not only solves the problem that catalyst slurry is severely adhered to the surface of an inner component, but also reduces heat transfer resistance in the normal operation process of the device and improves heat exchange efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of composite coatings, and in particular relates to a self-lubricating composite coating on the surface of an internal component substrate and a preparation method thereof. Background Art

[0002] During the shutdown process of the Fischer-Tropsch synthesis slurry bed reactor, the residual wax in the reactor needs to be unloaded. However, during the unloading process, part of the residual wax has a lower temperature and an increased viscosity, which can easily adhere to the surface of the internal components (including internal heat exchange tubes, support parts, cyclone separators, etc.) and form bridges. At present, the residual wax adhering to the surface of the internal components can only be cleaned manually, which is not only labor-intensive, but also has high safety risks and is time-consuming and labor-intensive.

[0003] CN113106443B discloses a 304 stainless steel coated with a self-lubricating wear-resistant composite coating and a preparation method thereof. The composite coating material is obtained from raw materials by laser cladding process, and the composite coating material includes the following raw materials: metal cobalt, metal copper and Ti3SiC2. The composite coating improves the hardness, wear resistance, corrosion resistance and self-lubricity of the composite coating. However, this solution mainly enhances the wear resistance of stainless steel, and its lubricity does not change much, and the invention is suitable for the manufacture of frictional moving parts such as piston rings, turbine blades and engine bearings.

[0004] CN103612438B discloses a treatment process for stainless steel products with non-stick surfaces. The solution introduces a treatment process for the non-stick surface of stainless steel products, including: (1) polishing (2) shot blasting (3) cleaning (4) spraying (5) sintering. The advantages of the invention are that the cleanliness of the stainless steel surface is enhanced, scale is avoided on the stainless steel surface, and the surface strength of the stainless steel non-stick product is improved. However, the solution is not suitable for high temperature and high pressure environments, and the surface coating contains chloride ions, and cannot be used for the surface coating of internal components of chemical equipment.

[0005] CN114351088A discloses a solid self-lubricating coating and its preparation method. The coating is composed of a hard diamond-like phase and a soft graphitized phase. It is characterized by high hardness, high load-bearing capacity, low wear and ultra-slip performance, and can provide wear-resistant lubrication protection for the substrate or workpiece under high load, high speed and other environments. The preparation method is simple, the operability is strong, and it is easy to industrialize. However, the cost of the invention technology is high, and the strength of the graphitized phase is low.

[0006] CN115926502A discloses a non-stick material and a preparation method thereof and a non-stick coating. The coating is composed of fatty acid metal salt particles and nano silicon dioxide particles. The coating is mainly used for surface treatment of cooking utensils to solve the "sticking pot" phenomenon. The disadvantage of the coating is that the surface is relatively rough and is not suitable for stainless steel surface treatment of chemical equipment.

[0007] In summary, although the prior art has conducted some research on composite coatings, there are still some adaptability issues for the substrates of internal components of chemical equipment. It is necessary to design a new internal component coating with anti-sticking function. Summary of the invention

[0008] In order to overcome the deficiencies in the prior art, the present invention provides a self-lubricating composite coating on the surface of the internal component substrate, which not only solves the problem of serious adhesion of catalyst slurry on the surface of the internal component during shutdown and maintenance, but also reduces heat transfer resistance and improves heat exchange efficiency during normal operation of the device due to the improved glossiness of the heat exchange tube surface.

[0009] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a self-lubricating composite coating on the surface of an internal component substrate, wherein the composite coating is covered on the surface of the internal component substrate and comprises a toughening layer in contact with the surface of the internal component substrate and a lubricating layer on the surface of the toughening layer;

[0011] The toughening layer is made of a titanium-rare earth mixture, and the lubricating layer is made of polytetrafluoroethylene and Ti3SiC2, wherein the toughening layer accounts for 70% to 95% of the thickness of the composite coating, such as 72%, 85%, 90%, and preferably 75% to 85%, such as 77%, 80%.

[0012] In the composite coating provided by the present invention, polytetrafluoroethylene and Ti3SiC2 are lubricating layers, which improve the surface finish and lubricity of the composite coating, and have excellent thermal conductivity, high elasticity, and self-lubricating properties. Polytetrafluoroethylene and Ti3SiC2 have different characteristics, support each other, and have a good synergistic effect, which can not only reduce the thickness of the toughening phase, but also improve the lubricity of the coating. In some specific embodiments, the mass proportion of polytetrafluoroethylene is 4% to 16%, such as 5%, 15%, preferably 6% to 10%, such as 8%, 9%.

[0013] In the composite coating provided by the present invention, in the toughening layer, the mass proportion of titanium is 75% to 90%, for example, 78%, 88%; preferably 80% to 85%, for example, 83%.

[0014] In some specific embodiments, in the titanium-rare earth mixture, the rare earth element is selected from one or more of scandium, praseodymium, neodymium, lanthanum, yttrium, niobium, cerium, ytterbium, dysprosium or terbium. In some preferred embodiments, the rare earth element can be selected from scandium, praseodymium, neodymium and niobium.

[0015] In a second aspect, the present invention provides a method for preparing the above-mentioned composite coating, comprising the following steps:

[0016] S1. Cleaning the surface of the inner component substrate to be surface treated to remove surface impurities;

[0017] S2, depositing a titanium-rare earth mixture on the surface of the inner component substrate after ultrasonic cleaning to form a toughening layer;

[0018] S3. Continue to deposit polytetrafluoroethylene and Ti3SiC2 on the surface of the inner component substrate where the toughening layer is formed to form a lubricating layer, thereby obtaining a self-lubricating composite coating.

[0019] In some specific implementations, ultrasound is used to clean the surface of the internal component in step S1; preferably, the frequency of the ultrasound is 60 to 98 KHz.

[0020] In the preparation method provided by the present invention, step S2 uses pulsed magnetron sputtering to deposit the titanium-rare earth mixture;

[0021] The conditions of the pulse magnetron sputtering method are: in an argon atmosphere, the flow rate of argon is 70-90 cm 3 / min, working gas pressure is 0.6~2.5Pa, substrate temperature is 300~500℃, bias power supply voltage is 150~190V, target power supply pulse frequency is 75~100KHz, target power supply power is 150~210kW, sputtering is 3~5h, and the target material is a titanium-rare earth mixture.

[0022] In a specific embodiment of the preparation method provided by the present invention, step S3 adopts pulse magnetron sputtering to deposit polytetrafluoroethylene and Ti3SiC2; the conditions of the pulse magnetron sputtering method are: in an argon atmosphere, the substrate temperature is 200-350°C, the bias power supply voltage is 160-200V, the target power supply pulse frequency is 70-110KHz, the target power supply power is 120-200kW, sputtering is 1-2h, and the target material is a mixture of polytetrafluoroethylene and Ti3SiC2.

[0023] The above technical solution has the following technical effects:

[0024] The composite coating provided by the present invention can prevent the slurry from adhering to the surface of the internal component due to condensation during shutdown, thereby reducing the workload of cleaning the condensed residual wax and shortening the maintenance cycle.

[0025] The composite coating provided by the present invention improves the glossiness of the heat exchange internal component and thus improves the heat transfer coefficient, thereby enhancing the heat transfer efficiency of the internal component. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : A specific embodiment of the self-lubricating composite coating on the surface of the internal component substrate provided by the present invention. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0028] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0029] In the following examples, the following methods were used to determine the performance indicators of the composite coating:

[0030] (1) Determination of heat transfer coefficient K: record the heat exchange area S, the temperature inside the heat exchange tube T1 and the slurry temperature T2, and the mass flow rate of the cold fluid q c , the cold fluid inlet and outlet enthalpy values ​​h1, h2, calculate the heat transfer Q = q c *(h2-h1), and then the heat transfer coefficient K can be calculated using the following formula: K=Q / [S*(T2-T1)];

[0031] (2) Coating tensile strength σ: refers to the ultimate ability of the interface between the coating and the substrate to withstand tensile stress in the normal direction, generally measured on a tensile testing machine;

[0032] (3) Coating surface gloss: refers to the glossiness of the coating surface, which reflects the coating surface's ability to reflect light. It is generally measured using a gloss meter.

[0033] Example 1

[0034] The self-lubricating composite coating (such as Figure 1 shown), including:

[0035] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0036] S2. A titanium-rare earth mixture (including praseodymium oxide, scandium and niobium) is prepared as a deposition target in a mass ratio of 6:1, and deposited on the surface of the cleaned internal component by magnetron sputtering. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0037] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:9, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0038] According to the test and analysis, the thickness of the toughening layer in the composite coating is 3000nm, the thickness of the lubricating layer is 500nm, the tensile strength of the composite coating is 1100MPa, the surface gloss is 75%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 3000W / (m 2 ×℃).

[0039] Example 2

[0040] The self-lubricating composite coating (such as Figure 1 shown), including:

[0041] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0042] S2. A deposition target prepared by a mixture of titanium-praseodymium oxide, scandium and niobium in a mass ratio of 3:1 is deposited on the surface of the cleaned internal component by a magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80 cm 3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0043] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:9, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0044] According to the test and analysis, the thickness of the toughening layer in the composite coating is 3100nm, the thickness of the lubricating layer is 500nm, the tensile strength of the composite coating is 1000MPa, the surface gloss is 74%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 2960W / (m2 ×℃).

[0045] Example 3

[0046] The self-lubricating composite coating (such as Figure 1 shown), including:

[0047] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0048] S2. A deposition target prepared by a mixture of titanium-praseodymium oxide, scandium and niobium in a mass ratio of 6:1 is deposited on the surface of the cleaned internal component by a magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80 cm 3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0049] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:14, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0050] According to the test and analysis, the thickness of the toughening layer in the composite coating is 3000nm, the thickness of the lubricating layer is 500nm, the tensile strength of the composite coating is 1100MPa, the surface gloss is 72%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 2800W / (m 2 ×℃).

[0051] Example 4

[0052] The self-lubricating composite coating (such as Figure 1 shown), including:

[0053] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0054] S2. A deposition target prepared by a mixture of titanium-metal lanthanum, ytterbium oxide, and yttrium oxide in a mass ratio of 6:1 is deposited on the surface of the cleaned internal component by a magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80 cm3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0055] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:9, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0056] According to the test and analysis, the thickness of the toughening layer in the composite coating is 2800nm, the thickness of the lubricating layer is 400nm, the tensile strength of the composite coating is 900MPa, the surface gloss is 70%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 2900W / (m 2 ×℃).

[0057] Comparative Example 1

[0058] The self-lubricating composite coating is prepared by the following method, comprising:

[0059] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0060] S2. A deposition target prepared by a mixture of titanium-praseodymium oxide, scandium and niobium in a mass ratio of 6:1 is deposited on the surface of the cleaned internal component by a magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80 cm 3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0061] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:25, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0062] According to the test and analysis, the thickness of the toughening layer in the composite coating is 3000nm, the thickness of the lubricating layer is 200nm, the tensile strength of the composite coating is 1000MPa, the surface gloss is 61%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 2680W / (m 2 ×℃).

[0063] Comparative Example 2

[0064] The self-lubricating composite coating is prepared by the following method, comprising:

[0065] S1. Perform ultrasonic cleaning on the surface of the inner component substrate at 80KHz to remove impurities on the surface;

[0066] S2. A deposition target prepared by a mixture of titanium-terbium oxide and yttrium-europium oxide in a mass ratio of 6:1 is deposited on the surface of the cleaned internal component by a magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80 cm 3 , the working gas pressure is 1.0Pa, the substrate temperature is 450℃, the bias power supply voltage is 150V, the target power supply pulse frequency is 90KHz, the target power supply power is 200kW, the sputtering time is 3h, and a toughening layer is deposited on the surface of the inner component substrate;

[0067] S3, polytetrafluoroethylene and Ti3SiC2 are used as deposition targets in a mass ratio of 1:9, and the deposition is continued on the toughening layer by using the magnetron sputtering method. The conditions of the pulsed magnetron sputtering method are: Ar is the working gas source, and the flow rate of argon is 80cm 3 , the substrate temperature is 260℃, the bias power supply voltage is 180V, the target power supply pulse frequency is 90KHz, the target power supply power is 180kW, the sputtering time is 2h, and a lubricating layer is deposited on the toughening layer.

[0068] According to the test and analysis, the thickness of the toughening layer in the composite coating obtained above is 2700nm, the thickness of the lubricating layer is 420nm, the tensile strength of the composite coating is 600MPa, the surface gloss is 71%, and the heat transfer coefficient of the heat exchanger coated with the composite coating is 2760W / (m 2 ×℃).

Claims

1. A self-lubricating composite coating on the surface of an internal component substrate, characterized in that: The composite coating is covered on the surface of the internal component substrate, and includes a toughening layer in contact with the surface of the internal component substrate and a lubricating layer on the surface of the toughening layer; The toughening layer is made of a titanium-rare earth mixture, and the lubricating layer is made of polytetrafluoroethylene and Ti3SiC2, wherein the toughening layer accounts for 70% to 95% of the thickness of the composite coating, preferably 75% to 85%.

2. The composite coating according to claim 1, characterized in that: During the preparation of the lubricating layer, the mass proportion of polytetrafluoroethylene is 4% to 16%.

3. The composite coating according to claim 2, characterized in that: During the preparation of the lubricating layer, the mass proportion of polytetrafluoroethylene is 6% to 10%.

4. The composite coating according to any one of claims 1 to 3, characterized in that: In the toughening layer, the mass proportion of titanium is 75% to 90%.

5. The composite coating according to claim 4, characterized in that: In the toughening layer, the mass proportion of titanium is 80% to 85%.

6. The composite coating according to claim 4, characterized in that: In the titanium-rare earth mixture, the rare earth element is selected from one or more of scandium, praseodymium, neodymium, lanthanum, yttrium, niobium, cerium, ytterbium, dysprosium or terbium; Preferred are scandium, praseodymium, neodymium and niobium.

7. The method for preparing a composite coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Cleaning the surface of the inner component substrate to be surface treated to remove surface impurities; S2, depositing a titanium-rare earth mixture on the surface of the inner component substrate after ultrasonic cleaning to form a toughening layer; S3. Continue to deposit polytetrafluoroethylene and Ti3SiC2 on the surface of the inner component substrate where the toughening layer is formed to form a lubricating layer, thereby obtaining a self-lubricating composite coating.

8. The preparation method according to claim 7, characterized in that: In step S1, the surface of the internal component is cleaned by ultrasound; Preferably, the frequency of the ultrasound is 60-98 KHz.

9. The preparation method according to claim 8, characterized in that: Step S2: Deposition of titanium-rare earth mixture by pulsed magnetron sputtering; The conditions of the pulse magnetron sputtering method are: in an argon atmosphere, the flow rate of argon is 70-90 cm 3 / min, working gas pressure is 0.6~2.5Pa, substrate temperature is 300~500℃, bias power supply voltage is 150~190V, target power supply pulse frequency is 75~100KHz, target power supply power is 150~210kW, sputtering is 3~5h, and the target material is a titanium-rare earth mixture.

10. The preparation method according to claim 9, characterized in that: Step S3: Deposition of polytetrafluoroethylene and Ti3SiC2 by pulsed magnetron sputtering; The conditions of the pulse magnetron sputtering method are: in an argon atmosphere, the substrate temperature is 200-350°C, the bias power supply voltage is 160-200V, the target power supply pulse frequency is 70-110KHz, the target power supply power is 120-200kW, the sputtering time is 1-2h, and the target material is a mixture of polytetrafluoroethylene and Ti3SiC2.

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