Preparation method for preparing high-temperature-resistant tungsten coating on surface of stainless steel base material

Abstract

The invention discloses a method for preparing a high-temperature-resistant tungsten coating on the surface of a stainless steel base material, and relates to the technical field of coating preparation on the surface of the base material, a direct-current magnetron sputtering mode is adopted for coating, and the method comprises the following steps that firstly, the base material directly faces a titanium target material, a bias power source and an HALL ion source are started, and plasma cleaning is conducted on the surface of the base material; secondly, after plasma cleaning is completed, a HALL power source is turned off, a direct-current magnetic control power source of the titanium target material is turned on, and titanium coating deposition is conducted; and (3) after the titanium coating is deposited, turning off the titanium target direct-current magnetic control power supply, enabling the base material to face the tungsten target material, and turning on the tungsten target material power supply to perform tungsten coating deposition. The intermediate metal film is introduced, the adhesion of the tungsten coating is improved, the tungsten coating with high purity and strong adhesive force is prepared on the surface of the stainless steel base material, the thickness of the high-temperature-resistant tungsten coating is controlled by adjusting magnetron sputtering process parameters, and then the high-temperature resistance of the 316 base material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing coatings on substrate surfaces, and in particular to a method for preparing high-temperature resistant tungsten coatings on the surface of a stainless steel substrate. Background Art

[0002] A tokamak is a magnetic confinement nuclear fusion experiment designed to simulate the nuclear fusion process occurring inside the sun and other stars. In this device, high-temperature plasma produces high-energy particles, which have a strong irradiation effect on the material. Tungsten has a very high melting point (approximately 3422°C) and can maintain structural stability at high temperatures, which is crucial for the parts of the tokamak that must withstand high temperatures and radiation.

[0003] Traditional methods for preparing high-temperature resistant coatings often suffer from issues such as weak bonding between the coating and the substrate, uneven coating thickness, and insufficient high-temperature resistance. 316 stainless steel is widely used in industry due to its excellent corrosion resistance and mechanical properties, but its oxidation resistance at high temperatures is limited.

[0004] Directly coating tungsten on a 316 stainless steel substrate can lead to poor adhesion between the film and the substrate due to differences in thermal expansion coefficients and mismatched chemical properties, making it prone to detachment. Furthermore, due to tungsten's high melting point, defects such as cracks and holes can easily form during the coating process, impacting the film's quality and performance. Summary of the Invention

[0005] Based on the current problems of insufficient adhesion between tungsten film and substrate, easy falling off, and easy generation of cracks and holes during the preparation process, the purpose of the present invention is to provide a preparation method for high-temperature resistant tungsten coating on the surface of stainless steel substrate. By using magnetron sputtering method, an intermediate metal film is introduced to improve the adhesion of tungsten coating, so as to realize the preparation of high-purity and strong adhesion tungsten coating on the surface of stainless steel substrate. Moreover, by adjusting the magnetron sputtering process parameters, the thickness of high-temperature resistant tungsten coating can be controlled, thereby improving the high-temperature resistance of 316 substrate.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present application provides a method for preparing a high-temperature resistant tungsten coating on the surface of a stainless steel substrate, which adopts a DC magnetron sputtering coating method, comprising the following steps:

[0008] Step 1: Place the substrate facing the titanium target, start the bias power supply and HALL ion source, and perform plasma cleaning on the substrate surface;

[0009] Step 2: After plasma cleaning is completed, the HALL power supply is turned off and the DC magnetron power supply of the titanium target is started to deposit the titanium coating;

[0010] Step 3: After the titanium coating is deposited, turn off the titanium target DC magnetron power supply, place the substrate directly against the tungsten target, start the tungsten target power supply, and deposit the tungsten coating.

[0011] The present invention adopts the physical deposition method of magnetron sputtering, and by introducing an intermediate metal film, weakens the difference in thermal expansion coefficient between coatings, improves the adhesion of the tungsten coating, and achieves strong bonding and uniformity of the tungsten coating on the substrate surface.

[0012] Furthermore, during plasma cleaning in step 1, the background vacuum of the chamber is 4×10 -3 Pa~6×10 - 3 Pa, the reaction vacuum degree of the cabin is 0.5Pa~2Pa.

[0013] Furthermore, the bias power in step 1 is 150W to 300W, and the HALL source power is 500W to 1000W.

[0014] Furthermore, when depositing the titanium coating in step 2, the reaction vacuum degree of the chamber is 0.5Pa to 2Pa.

[0015] Furthermore, in step 2, the DC magnetron power is 2 kW to 4 kW, and the deposition time is 10 min to 60 min.

[0016] Furthermore, when depositing the tungsten coating in step three, the reaction vacuum degree of the chamber is 0.5Pa to 2Pa.

[0017] Furthermore, when depositing the tungsten coating in step three, the DC magnetron power is 2kW to 4kW, and the deposition time is 30min to 120min.

[0018] The present invention realizes the controllable preparation of tungsten coating by controlling the process parameters during magnetron sputtering, thereby achieving the high-temperature resistance of the substrate. Compared with thin film materials prepared by other methods, the tungsten film prepared by DC magnetron sputtering with the introduction of a transition layer has significant advantages in performance.

[0019] During the entire coating process, applying a negative bias voltage to the workpiece can control the energy and quantity of ions reaching the substrate, improving sputtering efficiency and film quality. Secondly, HALL plasma cleaning and titanium coating deposition are key steps before tungsten coating deposition. HALL plasma cleaning removes dust and other contaminants from the substrate surface, activates molecules on the substrate surface, and breaks their chemical bonds, thereby increasing surface activity and providing a better foundation for subsequent coating adhesion, which in turn helps to improve bonding strength. Titanium, as a highly active metal material, acts as an intermediate layer in the coating, effectively enhancing the coating's bonding strength.

[0020] Furthermore, the stainless steel substrate includes a 316 stainless steel substrate.

[0021] Furthermore, the substrate is cleaned before being coated, comprising the following steps:

[0022] The substrate was placed in an acetone solution for ultrasonic cleaning;

[0023] The substrate was taken out of the acetone solution and ultrasonically cleaned with anhydrous ethanol to remove residual acetone;

[0024] The substrate was ultrasonically cleaned using deionized water to remove anhydrous ethanol;

[0025] After ultrasonic cleaning was completed, the substrate was taken out and dried with nitrogen gas.

[0026] Furthermore, before cleaning, the substrate is polished to remove any surface oxide layers, scratches, and burrs. Initially, dry mechanical polishing is performed using 800-grit sandpaper to remove minor scratches and oxide layers. Subsequently, the surface is refined and polished using wet mechanical polishing, using aluminum oxide as a polishing agent, to further refine the surface roughness and achieve a mirror finish.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] (1) The present invention loads a negative bias voltage on the substrate during the physical vapor deposition process, which can increase the energy of ions sputtered from the target surface when they reach the substrate. This increased energy helps to improve the sputtering efficiency and makes it easier for the ions to overcome the potential barrier on the substrate surface, thereby forming a thin film on the substrate.

[0029] (2) The present invention effectively improves the bonding strength between the coating and the substrate by depositing a titanium intermediate layer on a stainless steel substrate to meet the needs of industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0031] Figure 1 This is a digital photo of the 316 stainless steel substrate after tungsten plating in Example 4 of the present invention;

[0032] Figure 2These are metallographic micrographs of the 316 stainless steel substrates after tungsten plating in Examples 1, 2, 3, and 4 of the present invention at a magnification of 5 times; (a) represents the metallographic micrograph of Example 1, (b) represents the metallographic micrograph of Example 2, (c) represents the metallographic micrograph of Example 3, and (d) represents the metallographic micrograph of Example 4;

[0033] Figure 3 This is a metallographic microscopic cross-sectional view of a 316 stainless steel substrate after tungsten plating at 20 times magnification in Example 4 of the present invention;

[0034] Figure 4 These are metallographic micrographs of the 316 stainless steel substrates after tungsten plating in Example 4 of the present invention and Comparative Example 1 at a magnification of 5 times; (a) represents the metallographic micrograph of Comparative Example 1, and (b) represents the metallographic micrograph of Example 4. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0036] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, well-known materials or methods are not specifically described to avoid obscuring the present invention.

[0037] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, one skilled in the art will be able to combine and combine different embodiments or examples, and features of different embodiments or examples, described in this specification, without mutual inconsistency.

[0038] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] Example 1

[0040] This embodiment provides a method for preparing a high-temperature resistant tungsten coating on the surface of a stainless steel substrate, using DC magnetron sputtering to coat the film. A 316 stainless steel substrate with a size of 40*40mm and a thickness of 5mm is selected. The specific preparation method is as follows:

[0041] S1. Substrate pretreatment

[0042] S1-1. Polish the 316 substrate to remove defects such as oxide layer, scratches and burrs on the substrate surface. Initially, dry mechanical polishing method is adopted, and 800 grit sandpaper is used to perform preliminary grinding on the substrate surface to remove tiny scratches and oxide layer on the surface.

[0043] S1-2, enter the fine polishing stage, use aluminum oxide as a polishing agent, through mechanical polishing, further refine the surface roughness to achieve a mirror effect.

[0044] S2. Substrate cleaning

[0045] Before coating, a cleaning step is required to remove grease and rust from the surface of the 316 substrate to ensure that the coating adheres firmly. The substrate is ultrasonically cleaned using an ultrasonic cleaning tank.

[0046] S2-1. Place the substrate in an acetone solution, set the ultrasonic vibration frequency to 28 kHz, and perform ultrasonic cleaning for 10 minutes.

[0047] S2-2. Remove the substrate from the acetone solution and ultrasonically clean the substrate with anhydrous ethanol for 10 minutes to remove the residual acetone from the previous step.

[0048] S2-3. Use deionized water to ultrasonically clean the substrate to remove the anhydrous ethanol in the previous step, and ultrasonically clean for 10 minutes.

[0049] S2-4. After ultrasonic cleaning is completed, the substrate is taken out and dried with nitrogen.

[0050] S3, substrate clamping

[0051] Use steel bars to install and fix the 316 stainless steel substrate. After the fixation is completed, place the substrate workpiece into the vacuum chamber of the magnetron sputtering coating system and adjust it to the appropriate position. After confirming that all components of the coating system are normal, close the vacuum chamber door.

[0052] S4, magnetron sputtering coating

[0053] Start the mechanical pump, Roots pump, molecular pump, etc. of the magnetron sputtering coating system in sequence to evacuate the vacuum chamber. After the vacuum degree of the chamber reaches the background vacuum degree, introduce high-purity argon gas with a purity of 99.99% to adjust the reaction vacuum degree of the chamber.

[0054] S4-1, through the revolution and rotation, the substrate is placed directly against the titanium target, the bias power supply and the HALL ion source are started, and the surface of the substrate is plasma cleaned. The background vacuum of the chamber is 4×10 -3 Argon gas was introduced to make the reaction chamber vacuum degree 0.5 Pa, the bias power was set to 150 W, the HALL plasma cleaning power was set to 1000 W, and the cleaning time was set to 20 min.

[0055] After plasma cleaning is complete, turn off the Hall power supply and activate the DC magnetron power supply for the titanium target. The workpiece is aligned with the titanium target through revolution and rotation. The titanium target power supply is activated to begin titanium coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the titanium target magnetron power supply is 3.3 kW, and the deposition time is set to 30 minutes.

[0056] After the titanium coating is deposited, the titanium target DC magnetron power supply is turned off. The workpiece is then aligned with the tungsten target through revolution and rotation. The tungsten target power supply is then turned on to begin tungsten coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the tungsten target magnetron power supply is 3.5 kW, and the deposition time is set to 30 minutes.

[0057] After the deposition is completed, turn off the magnetron power supply, and turn off the molecular pump, Roots pump, mechanical pump, etc. in turn to shut down the magnetron sputtering coating system.

[0058] Example 2

[0059] This embodiment provides a method for preparing a high-temperature resistant tungsten coating on a stainless steel substrate. The coating is deposited using a DC magnetron sputtering method. A 316 stainless steel substrate with dimensions of 40*40mm and a thickness of 5mm is selected. Unlike Example 1, the tungsten coating is deposited for 60 minutes in this embodiment. Other technical features are the same as in Example 1. The specific preparation method is as follows:

[0060] S1. Substrate pretreatment

[0061] S1-1. Polish the 316 substrate to remove defects such as oxide layer, scratches and burrs on the substrate surface. Initially, dry mechanical polishing method is adopted, and 800 grit sandpaper is used to perform preliminary grinding on the substrate surface to remove tiny scratches and oxide layer on the surface.

[0062] S1-2, enter the fine polishing stage, use aluminum oxide as a polishing agent, through mechanical polishing, further refine the surface roughness to achieve a mirror effect.

[0063] S2. Substrate cleaning

[0064] Before coating, a cleaning step is required to remove grease and rust from the surface of the 316 substrate to ensure that the coating adheres firmly. The substrate is ultrasonically cleaned using an ultrasonic cleaning tank.

[0065] S2-1. Place the substrate in an acetone solution, set the ultrasonic vibration frequency to 28 kHz, and perform ultrasonic cleaning for 10 minutes.

[0066] S2-2. Remove the substrate from the acetone solution and ultrasonically clean the substrate with anhydrous ethanol for 10 minutes to remove the residual acetone from the previous step.

[0067] S2-3. Use deionized water to ultrasonically clean the substrate to remove the anhydrous ethanol in the previous step, and ultrasonically clean for 10 minutes.

[0068] S2-4. After ultrasonic cleaning is completed, the substrate is taken out and dried with nitrogen.

[0069] S3, substrate clamping

[0070] Use steel bars to install and fix the 316 stainless steel substrate. After the fixation is completed, place the substrate workpiece into the vacuum chamber of the magnetron sputtering coating system and adjust it to the appropriate position. After confirming that all components of the coating system are normal, close the vacuum chamber door.

[0071] S4, magnetron sputtering coating

[0072] Start the mechanical pump, Roots pump, molecular pump, etc. of the magnetron sputtering coating system in sequence to evacuate the vacuum chamber. After the vacuum degree of the chamber reaches the background vacuum degree, introduce high-purity argon gas with a purity of 99.99% to adjust the reaction vacuum degree of the chamber.

[0073] S4-1, through the revolution and rotation, the substrate is placed directly against the titanium target, the bias power supply and the HALL ion source are started, and the surface of the substrate is plasma cleaned. The background vacuum of the chamber is 4×10 -3 Argon gas was introduced to make the reaction chamber vacuum degree 0.5 Pa, the bias power was set to 150 W, the HALL plasma cleaning power was set to 1000 W, and the cleaning time was set to 20 min.

[0074] After plasma cleaning is complete, turn off the Hall power supply and activate the DC magnetron power supply for the titanium target. The workpiece is aligned with the titanium target through revolution and rotation. The titanium target power supply is activated to begin titanium coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the titanium target magnetron power supply is 3.3 kW, and the deposition time is set to 30 minutes.

[0075] After the titanium coating is deposited, the titanium target DC magnetron power supply is turned off. The workpiece is then aligned with the tungsten target through revolution and rotation. The tungsten target power supply is then turned on to begin tungsten coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the tungsten target magnetron power supply is 3.5 kW, and the deposition time is set to 60 minutes.

[0076] After the deposition is completed, turn off the magnetron power supply, and turn off the molecular pump, Roots pump, mechanical pump, etc. in turn to shut down the magnetron sputtering coating system.

[0077] Example 3

[0078] This embodiment provides a method for preparing a high-temperature resistant tungsten coating on a stainless steel substrate. The coating is deposited using DC magnetron sputtering. A 316 stainless steel substrate with dimensions of 40 x 40 mm and a thickness of 5 mm is used. Unlike Example 1, the tungsten coating is deposited for 90 minutes in this embodiment. Other technical features are the same as in Example 1. The specific preparation method is as follows:

[0079] S1. Substrate pretreatment

[0080] S1-1. Polish the 316 substrate to remove defects such as oxide layer, scratches and burrs on the substrate surface. Initially, dry mechanical polishing method is adopted, and 800 grit sandpaper is used to perform preliminary grinding on the substrate surface to remove tiny scratches and oxide layer on the surface.

[0081] S1-2, enter the fine polishing stage, use aluminum oxide as a polishing agent, through mechanical polishing, further refine the surface roughness to achieve a mirror effect.

[0082] S2. Substrate cleaning

[0083] Before coating, a cleaning step is required to remove grease and rust from the surface of the 316 substrate to ensure that the coating adheres firmly. The substrate is ultrasonically cleaned using an ultrasonic cleaning tank.

[0084] S2-1. Place the substrate in an acetone solution, set the ultrasonic vibration frequency to 28 kHz, and perform ultrasonic cleaning for 10 minutes.

[0085] S2-2. Remove the substrate from the acetone solution and ultrasonically clean the substrate with anhydrous ethanol for 10 minutes to remove the residual acetone from the previous step.

[0086] S2-3. Use deionized water to ultrasonically clean the substrate to remove the anhydrous ethanol in the previous step, and ultrasonically clean for 10 minutes.

[0087] S2-4. After ultrasonic cleaning is completed, the substrate is taken out and dried with nitrogen.

[0088] S3, substrate clamping

[0089] Use steel bars to install and fix the 316 stainless steel substrate. After the fixation is completed, place the substrate workpiece into the vacuum chamber of the magnetron sputtering coating system and adjust it to the appropriate position. After confirming that all components of the coating system are normal, close the vacuum chamber door.

[0090] S4, magnetron sputtering coating

[0091] Start the mechanical pump, Roots pump, molecular pump, etc. of the magnetron sputtering coating system in sequence to evacuate the vacuum chamber. After the vacuum degree of the chamber reaches the background vacuum degree, introduce high-purity argon gas with a purity of 99.99% to adjust the reaction vacuum degree of the chamber.

[0092] S4-1, through the revolution and rotation, the substrate is placed directly against the titanium target, the bias power supply and the HALL ion source are started, and the surface of the substrate is plasma cleaned. The background vacuum of the chamber is 4×10 -3 Argon gas was introduced to make the reaction chamber vacuum degree 0.5 Pa, the bias power was set to 150 W, the HALL plasma cleaning power was set to 1000 W, and the cleaning time was set to 20 min.

[0093] After plasma cleaning is complete, turn off the Hall power supply and activate the DC magnetron power supply for the titanium target. The workpiece is aligned with the titanium target through revolution and rotation. The titanium target power supply is activated to begin titanium coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the titanium target magnetron power supply is 3.3 kW, and the deposition time is set to 30 minutes.

[0094] After the titanium coating is deposited, the titanium target DC magnetron power supply is turned off. The workpiece is then aligned with the tungsten target through revolution and rotation. The tungsten target power supply is then turned on to begin tungsten coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the tungsten target magnetron power supply is 3.5 kW, and the deposition time is set to 90 minutes.

[0095] After the deposition is completed, turn off the magnetron power supply, and turn off the molecular pump, Roots pump, mechanical pump, etc. in turn to shut down the magnetron sputtering coating system.

[0096] Example 4

[0097] This embodiment provides a method for preparing a high-temperature resistant tungsten coating on a stainless steel substrate. The coating is deposited using DC magnetron sputtering. A 316 stainless steel substrate with dimensions of 40 x 40 mm and a thickness of 5 mm is used. Unlike Example 1, the tungsten coating is deposited for 120 minutes in this embodiment. Other technical features are the same as in Example 1. The specific preparation method is as follows:

[0098] S1. Substrate pretreatment

[0099] S1-1. Polish the 316 substrate to remove defects such as oxide layer, scratches and burrs on the substrate surface. Initially, dry mechanical polishing method is adopted, and 800 grit sandpaper is used to perform preliminary grinding on the substrate surface to remove tiny scratches and oxide layer on the surface.

[0100] S1-2, enter the fine polishing stage, use aluminum oxide as a polishing agent, through mechanical polishing, further refine the surface roughness to achieve a mirror effect.

[0101] S2. Substrate cleaning

[0102] Before coating, a cleaning step is required to remove grease and rust from the surface of the 316 substrate to ensure that the coating adheres firmly. The substrate is ultrasonically cleaned using an ultrasonic cleaning tank.

[0103] S2-1. Place the substrate in an acetone solution, set the ultrasonic vibration frequency to 28 kHz, and perform ultrasonic cleaning for 10 minutes.

[0104] S2-2. Remove the substrate from the acetone solution and ultrasonically clean the substrate with anhydrous ethanol for 10 minutes to remove the residual acetone from the previous step.

[0105] S2-3. Use deionized water to ultrasonically clean the substrate to remove the anhydrous ethanol in the previous step, and ultrasonically clean for 10 minutes.

[0106] S2-4. After ultrasonic cleaning is completed, the substrate is taken out and dried with nitrogen.

[0107] S3, substrate clamping

[0108] Use steel bars to install and fix the 316 stainless steel substrate. After the fixation is completed, place the substrate workpiece into the vacuum chamber of the magnetron sputtering coating system and adjust it to the appropriate position. After confirming that all components of the coating system are normal, close the vacuum chamber door.

[0109] S4, magnetron sputtering coating

[0110] Start the mechanical pump, Roots pump, molecular pump, etc. of the magnetron sputtering coating system in sequence to evacuate the vacuum chamber. After the vacuum degree of the chamber reaches the background vacuum degree, introduce high-purity argon gas with a purity of 99.99% to adjust the reaction vacuum degree of the chamber.

[0111] S4-1, through the revolution and rotation, the substrate is placed directly against the titanium target, the bias power supply and the HALL ion source are started, and the surface of the substrate is plasma cleaned. The background vacuum of the chamber is 4×10 -3 Argon gas was introduced to make the reaction chamber vacuum degree 0.5 Pa, the bias power was set to 150 W, the HALL plasma cleaning power was set to 1000 W, and the cleaning time was set to 20 min.

[0112] After plasma cleaning is complete, turn off the Hall power supply and activate the DC magnetron power supply for the titanium target. The workpiece is aligned with the titanium target through revolution and rotation. The titanium target power supply is activated to begin titanium coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the titanium target magnetron power supply is 3.3 kW, and the deposition time is set to 30 minutes.

[0113] After the titanium coating is deposited, the titanium target DC magnetron power supply is turned off. The workpiece is then aligned with the tungsten target through revolution and rotation. The tungsten target power supply is then turned on to begin tungsten coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the tungsten target magnetron power supply is 3.5 kW, and the deposition time is set to 120 minutes.

[0114] After the deposition is completed, turn off the magnetron power supply, and turn off the molecular pump, Roots pump, mechanical pump, etc. in turn to shut down the magnetron sputtering coating system.

[0115] like Figure 1 As shown in FIG, after the Ti transition layer is selected in this embodiment, the stress of the tungsten coating is well released during the preparation process. Even after 120 minutes of deposition, the surface of the tungsten coating is smooth and no cracks appear. The tungsten coatings prepared by the methods of Examples 1, 2, 3 and 4 were subjected to metallographic testing. The results are shown in FIG. Figure 2 As shown in FIG, it is observed that as the deposition time increases, no obvious cracks appear on the film surface, and only a small amount of scratches exist on the film surface after 120 minutes of tungsten deposition. Figure 3As shown, further observation from the cross section shows that the film layer has good adhesion and no falling off occurs. The film layer is uniform and has a thickness of about 17.94 μm.

[0116] Comparative Example 1

[0117] This comparative example provides a method for preparing a high-temperature resistant tungsten coating on a stainless steel substrate. The coating is deposited using a DC magnetron sputtering method. A 316 stainless steel substrate with dimensions of 40 x 40 mm and a thickness of 5 mm is selected. Unlike Example 1, no titanium coating is deposited in this comparative example. The specific preparation method is as follows:

[0118] S1. Substrate pretreatment

[0119] S1-1. Polish the 316 substrate to remove defects such as oxide layer, scratches and burrs on the substrate surface. Initially, dry mechanical polishing method is adopted, and 800 grit sandpaper is used to perform preliminary grinding on the substrate surface to remove tiny scratches and oxide layer on the surface.

[0120] S1-2, enter the fine polishing stage, use aluminum oxide as a polishing agent, through mechanical polishing, further refine the surface roughness to achieve a mirror effect.

[0121] S2. Substrate cleaning

[0122] Before coating, a cleaning step is required to remove grease and rust from the surface of the 316 substrate to ensure that the coating adheres firmly. The substrate is ultrasonically cleaned using an ultrasonic cleaning tank.

[0123] S2-1. Place the substrate in an acetone solution, set the ultrasonic vibration frequency to 28 kHz, and perform ultrasonic cleaning for 10 minutes.

[0124] S2-2. Remove the substrate from the acetone solution and ultrasonically clean the substrate with anhydrous ethanol for 10 minutes to remove the residual acetone from the previous step.

[0125] S2-3. Use deionized water to ultrasonically clean the substrate to remove the anhydrous ethanol in the previous step, and ultrasonically clean for 10 minutes.

[0126] S2-4. After ultrasonic cleaning is completed, the substrate is taken out and dried with nitrogen.

[0127] S3, substrate clamping

[0128] Use steel bars to install and fix the 316 stainless steel substrate. After the fixation is completed, place the substrate workpiece into the vacuum chamber of the magnetron sputtering coating system and adjust it to the appropriate position. After confirming that all components of the coating system are normal, close the vacuum chamber door.

[0129] S4, magnetron sputtering coating

[0130] Start the mechanical pump, Roots pump, molecular pump, etc. of the magnetron sputtering coating system in sequence to evacuate the vacuum chamber. After the vacuum degree of the chamber reaches the background vacuum degree, introduce high-purity argon gas with a purity of 99.99% to adjust the reaction vacuum degree of the chamber.

[0131] S4-1. Place the substrate facing the tungsten target, start the bias power supply and HALL ion source, and perform plasma cleaning on the substrate surface. The chamber background vacuum is 4×10 -3 Argon gas was introduced to make the reaction chamber vacuum degree 0.5 Pa, the bias power was set to 150 W, the HALL plasma cleaning power was set to 1000 W, and the cleaning time was set to 20 min.

[0132] After plasma cleaning is complete, turn off the Hall power supply and activate the DC magnetron power supply for the tungsten target. The workpiece is aligned with the tungsten target through revolution and rotation. The tungsten target power supply is activated to begin tungsten coating deposition. During deposition, the chamber vacuum is maintained at 0.5 Pa, the tungsten target magnetron power supply is 3.5 kW, and the deposition time is set to 40 minutes.

[0133] After the deposition is completed, turn off the magnetron power supply, and turn off the molecular pump, Roots pump, mechanical pump, etc. in turn to shut down the magnetron sputtering coating system.

[0134] The tungsten coatings prepared by the methods of Example 4 and Comparative Example 1 were subjected to metallographic testing. The results are as follows: Figure 4 As shown, in Figure 4 In (a), it is observed that after 40 minutes of tungsten plating directly on the 316 stainless steel substrate, a large number of irregular cracks appear in the tungsten film layer, and the film uniformity is poor; Figure 4 In (b), it is observed that when there is an intermediate layer of titanium metal, even after 120 minutes of tungsten plating, there are only a few scratches on the surface of the tungsten film layer, and the film layer has good adhesion and uniformity.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that it is still possible to modify the technical solutions described in the above embodiments, or to replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate, characterized in that: The coating is deposited by DC magnetron sputtering, including the following steps: Step 1: Place the substrate facing the titanium target, start the bias power supply and the HALL ion source, and perform plasma cleaning on the surface of the substrate; Step 2: After the plasma cleaning is completed, the HALL power supply is turned off, and the DC magnetron power supply of the titanium target is started to deposit the titanium coating; Step 3: After the titanium coating is deposited, turn off the DC magnetron power supply of the titanium target, place the substrate directly against the tungsten target, start the tungsten target power supply, and deposit the tungsten coating.

2. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: During plasma cleaning in step 1, the background vacuum of the chamber is 4×10 -3 Pa~6×10 -3 Pa, the reaction vacuum of the cabin is 0.5Pa~2Pa.

3. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: The bias power in step 1 is 150W to 300W, and the HALL source power is 500W to 1000W.

4. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: When the titanium coating is deposited in step 2, the reaction vacuum degree of the chamber is 0.5Pa to 2Pa.

5. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: In step 2, the DC magnetron power is 2 kW to 4 kW, and the deposition time is 10 min to 60 min.

6. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: When the tungsten coating is deposited in step 3, the reaction vacuum degree of the chamber is 0.5Pa to 2Pa.

7. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: When depositing the tungsten coating in step 3, the DC magnetron power is 2kW to 4kW, and the deposition time is 30min to 120min.

8. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: The stainless steel substrate includes a 316 stainless steel substrate.

9. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 1, characterized in that: The substrate is cleaned before coating, including the following steps: The substrate is placed in an acetone solution for ultrasonic cleaning; The substrate is taken out from the acetone solution, and the substrate is ultrasonically cleaned using anhydrous ethanol to remove residual acetone; The substrate was ultrasonically cleaned using deionized water to remove anhydrous ethanol; After ultrasonic cleaning, the substrate was taken out and dried with nitrogen.

10. The method for preparing a high temperature resistant tungsten coating on the surface of a stainless steel substrate according to claim 9, characterized in that: Before cleaning the substrate, the substrate is polished to remove the oxide layer, scratches and burrs on the surface of the substrate.

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