Special stainless steel for magnetic sensor base and manufacturing process thereof

Abstract

The application discloses a special stainless steel for a magnetic sensing base and a manufacturing process thereof, and relates to the technical field of stainless steel. The process comprises the following steps: after polishing and polishing a ferrite stainless steel base material, the ferrite stainless steel base material is cleaned and dried to obtain a pretreated ferrite stainless steel base material; after preheating, the ferrite stainless steel base material is subjected to one-time thermal spraying of a composite powder A; after forming a coating A on the surface of the pretreated ferrite stainless steel base material, the ferrite stainless steel base material is subjected to two-time thermal spraying of a composite powder B; after forming a coating B on the surface of the coating A, the ferrite stainless steel base material is polished, polished and cleaned to obtain a ferrite stainless steel base material with a gradient coating; the ferrite stainless steel base material is subjected to ion beam injection; the ferrite stainless steel base material is subjected to low-oxygen partial pressure heat treatment; finally, the ferrite stainless steel base material is subjected to plasma enhanced chemical vapor deposition of a DLC film to obtain the special stainless steel for the magnetic sensing base. The ferrite stainless steel is subjected to surface treatment such as thermal spraying, so that the wear resistance and corrosion resistance of the ferrite stainless steel under complex working conditions are improved.

Description

Technical Field

[0001] This invention relates to the field of stainless steel technology, specifically to a special stainless steel for magnetic bases and its manufacturing process. Background Technology

[0002] As a key functional component in high and medium voltage electrical appliances for achieving magnetic circuit closure and position sensing, the magnetic induction base is typically made of ferritic stainless steel, such as the 430 and 439 series. This type of soft magnetic material faces complex challenges during actual service: on the one hand, frequent opening and closing operations of high-voltage electrical appliances cause fretting wear and impact loads between the base and the mating components, requiring high surface hardness and a low coefficient of friction; on the other hand, this component is exposed to water vapor, salt spray, and industrial atmospheres in outdoor or humid environments for extended periods, requiring excellent corrosion resistance. Therefore, as a critical component of the magnetic circuit, the surface modification of the magnetic induction base needs to achieve a strict balance between magnetic properties, wear resistance, and corrosion resistance. In summary, there is an urgent need for a manufacturing process that can modify the surface of ferritic stainless steel to achieve long-term reliable service of the magnetic base under complex working conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a special stainless steel for magnetic bases and its manufacturing process to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A manufacturing process for a special stainless steel base for magnetic induction includes the following steps: Step 1: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form coating A on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form coating B on the surface of coating A. After grinding, polishing and cleaning, a ferritic stainless steel substrate with a gradient coating is obtained. Step 2: Take a ferritic stainless steel substrate with a gradient coating, perform ion beam implantation, then perform low oxygen partial pressure heat treatment, and finally perform plasma-enhanced chemical vapor deposition to deposit a DLC film on the coating surface to obtain a special stainless steel for magnetic base. Preferably, the chemical composition of the ferritic stainless steel substrate is as follows: by mass percentage, Cr: 16-18%, C≤0.065%, Si≤0.5%, Mn≤0.6%, Mo≤1.5%, Ni≤0.2%, P≤0.02%, with the balance being Fe and unavoidable impurities; Preferably, composite powder A comprises the following raw materials in parts by weight: 70-80 parts nickel-iron alloy powder, 5-10 parts cobalt ferrite powder, and 10-25 parts carbide metal powder. Preferably, composite powder B comprises the following raw materials in parts by weight: 40-50 parts nickel-iron alloy powder, 2-7.5 parts cobalt ferrite powder, and 30-45 parts carbide metal powder; Among them, the carbide metal powder is any one of WC-CoCr, Cr3C2-NiCr, and WC-Cr3C2-Ni; The chemical composition of the nickel-iron alloy powder is: Fe: 16-20%, Cr: 8-10%, Si: 3-5%, Al: 2-3%, and the balance is Ni; The preheating process parameters are: temperature 120℃, holding time 2h; Preferably, the process parameters for a single thermal spraying are: oxygen pressure 0.4-0.8 MPa, propane pressure 0.3-0.4 MPa, compressed air pressure 0.2-0.5 MPa, and powder feeding rate 20-30 g / min. -1 Spraying distance: 80-100mm; Carrier gas pressure: 0.6-0.8MPa; Carrier gas flow rate: 50-80L·min -1 Horizontal velocity of the gun barrel: 200-300 mm / s -1 The horizontal spacing between single lanes is 2-3mm; Preferably, the process parameters for secondary thermal spraying are: oxygen pressure 0.6-0.8 MPa, propane pressure 0.3-0.5 MPa, compressed air pressure 0.2-0.5 MPa, and powder feeding rate 20-30 g·min. -1 Spraying distance: 150-200mm; Carrier gas pressure: 0.8-1.0MPa; Carrier gas flow rate: 50-80L·min -1 Horizontal velocity of the gun barrel: 300-500 mm / s -1 The horizontal spacing between single lanes is 3-5mm; Preferably, the ion beam implantation process parameters are: using a MEVVA implantation source, with a yttrium ion composition of 3-5% Y. + 60-64%Y 2+ 32-35%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 40-50kV, 80-90kV, and 100-120kV, respectively; the cerium ion composition was 3-5%Ce. + 80-85% Ce 2+ 10-17% Ce 3+ Ce + Ce 2+ Ce 3+The accelerating voltages were 30-40kV, 90-100kV, and 110-120kV, respectively; the implantation amounts of yttrium and cerium ions were both (2-5)×10⁻⁶. 16 / cm 2 The beam current density is 12-15 μA / cm. 2 ; More preferably, the process parameters for low oxygen partial pressure heat treatment are: temperature of 600-700℃ and oxygen partial pressure of (1-5)×10⁻⁶. -4 Pa, heat treatment time 2-3h; Preferably, the thickness of coating A is 50-60 μm and the thickness of coating B is 80-90 μm; the coating is then polished until the total thickness is reduced by 15-20 μm. Preferably, the DLC thin film preparation steps are as follows: preheating the substrate to 180-200°C, and maintaining a vacuum degree of 5×10⁻⁶. -3 After plasma etching for 20-40 minutes, a transition layer of Cr with a thickness of 0.8-1.0 μm was magnetron sputtered, followed by DLC deposition using hydrogen-diluted acetylene as a precursor. The partial pressure of acetylene was 0.8-1.2 Pa, and the partial pressure of hydrogen was 0.1-0.3 Pa. The pulse bias voltage was set to -600~-800V, the frequency was 40-60kHz, and the duty cycle was 30-40%. After deposition for 2-3 hours, the furnace was cooled.

[0005] A special stainless steel for magnetic bases is prepared by the above-mentioned manufacturing process.

[0006] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention employs thermal spraying, ion implantation, low-oxygen partial pressure heat treatment, and chemical vapor deposition (DLC) thin film to treat the surface of ferritic stainless steel. First, thermally sprayed composite powder A uses a ratio of high-nickel iron alloy and low-carbide, while composite powder B uses a ratio of low-nickel iron alloy and high-carbide to form a gradient coating, ensuring certain magnetic properties. The nickel iron alloy uses a Ni-Cr-Fe-Si-Al ratio, which wets the substrate and fills powder pores during thermal spraying, enhancing the coating's density and simultaneously coating the carbides, providing a certain degree of wear resistance. This improves the bonding strength and corrosion resistance between the coating and the substrate. Based on this, dual rare-earth ion beam implantation is performed to enhance the coating's corrosion resistance. Then, low-oxygen partial pressure heat treatment is performed to inhibit excessive oxidation while promoting the diffusion of rare earth elements in the coating, forming a dense rare-earth oxide barrier layer. This provides a low-oxygen, clean surface for subsequent DLC thin film deposition, improving the interfacial bonding between the coating and the DLC. Plasma-enhanced chemical vapor deposition is used to prepare a hydrogen-containing DLC ​​thin film on the coating surface, further enhancing corrosion and wear resistance. Detailed Implementation

[0007] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0008] It should be noted that the following quantities are by weight, and there are no special restrictions on the suppliers of all raw materials involved in this invention. Exemplary examples include: The chemical composition of the ferritic stainless steel substrate is as follows (by mass percentage): Cr: 17.86%, C: 0.06%, Si: 0.02%, Mn: 0.6%, Mo: 1.2%, Ni: 0.05%, P: 0.02%, with the balance being Fe and unavoidable impurities; the dimensions of the ferritic stainless steel substrate are 10mm × 10mm × 3mm. The chemical composition of the nickel-iron alloy powder is: Fe: 18.33%, Cr: 9.08%, Si: 4.32%, Al: 2.48%, and the balance is Ni; The cobalt ferrite powder has a particle size of 30 nm; WC-CoCr consists of 80 wt% WC and 20 wt% CoCr; Cr3C2-NiCr consists of 75 wt% Cr3C2 and 25 wt% NiCr; WC-Cr3C2-Ni consists of 70 wt% WC, 22 wt% Cr3C2 and 8 wt% Ni. In the following examples, parts refer to parts by weight, and all raw materials mentioned above and others not mentioned are commercially available.

[0009] Example 1: This example provides a manufacturing process for a special stainless steel, specifically including the following steps: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 75 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 18 parts WC-CoCr; composite powder B includes the following raw materials by mass parts: 45 parts nickel-iron alloy powder, 5 parts cobalt ferrite powder, and 40 parts WC-CoCr. Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a coating A with a thickness of 55μm on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form a coating B with a thickness of 85μm on the surface of coating A. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a gradient coating, followed by low oxygen partial pressure heat treatment at a temperature of 650℃ and an oxygen partial pressure of 3×10⁻⁶. -4 After heat treatment at Pa for 2 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.6 MPa, propane pressure 0.35 MPa, compressed air pressure 0.35 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 90mm, carrier gas pressure 0.7MPa, carrier gas flow rate 65L·min -1 Barrel horizontal velocity 250 mm / s -1 Single-lane horizontal spacing 2mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.7 MPa, propane pressure 0.4 MPa, compressed air pressure 0.4 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 150mm, carrier gas pressure 0.8MPa, carrier gas flow rate 70L·min -1 Barrel horizontal velocity 350 mm / s -1 Single-lane horizontal spacing 3mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 5% Y. + 62%Y 2+ 33%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 40kV, 80kV, and 120kV, respectively; the cerium ion composition was 4%Ce. + 82% Ce 2+ 14% Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 40 kV, 100 kV, and 120 kV, respectively; the implantation amounts of yttrium and cerium ions were both 3 × 10⁻⁶. 16 / cm 2 The beam current density is 13.5 μA / cm. 2 ; The preparation steps for DLC thin films are as follows: preheat the substrate to 200°C, and maintain a vacuum level of 5×10⁻⁶. -3After plasma etching with Ar:H2 = 1:1 for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using hydrogen-diluted acetylene as a precursor, with an acetylene partial pressure of 1.0 Pa and a hydrogen partial pressure of 0.2 Pa. The pulse bias voltage was set to -600 V, the frequency to 60 kHz, and the duty cycle to 30%. After deposition for 2 h, the furnace was cooled.

[0010] Example 2: This example provides a manufacturing process for a special stainless steel, specifically including the following steps: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 70 parts nickel-iron alloy powder, 10 parts cobalt ferrite powder, and 20 parts Cr3C2-NiCr; composite powder B includes the following raw materials by mass parts: 40 parts nickel-iron alloy powder, 7.5 parts cobalt ferrite powder, and 42.5 parts Cr3C2-NiCr; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a 60μm thick coating A on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form an 80μm thick coating B on the surface of coating A. After grinding, polishing and cleaning until the total coating thickness is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a gradient coating, followed by low oxygen partial pressure heat treatment at a temperature of 700℃ and an oxygen partial pressure of 3×10⁻⁶. -4 After heat treatment at Pa for 2 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.6 MPa, propane pressure 0.4 MPa, compressed air pressure 0.5 MPa, and powder feeding rate 30 g / min. -1 Spraying distance 100mm, carrier gas pressure 0.8MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.8 MPa, propane pressure 0.5 MPa, compressed air pressure 0.5 MPa, and powder feeding rate 30 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 500 mm / s -1 Single-lane horizontal spacing 5mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 5% Y. + 60%Y 2+ 35%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 50kV, 80kV, and 120kV, respectively; the cerium ion composition was 5%Ce. + 85% Ce 2+ 10% Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 40 kV, 100 kV, and 120 kV; the implantation amounts of yttrium and cerium ions were both 5 × 10⁻⁶. 16 / cm 2 The beam current density is 15 μA / cm. 2 ; The preparation steps for DLC thin films are as follows: preheat the substrate to 200°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.8 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.0 Pa and a hydrogen partial pressure of 0.1 Pa. The pulse bias voltage was set to -800 V, the frequency to 60 kHz, and the duty cycle to 35%. After deposition for 2 h, the furnace was cooled.

[0011] Example 3: This example provides a manufacturing process for a special stainless steel, specifically including the following steps: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 80 parts nickel-iron alloy powder, 5 parts cobalt ferrite powder, and 25 parts WC-Cr3C2-Ni; composite powder B includes the following raw materials by mass parts: 50 parts nickel-iron alloy powder, 5 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a 50μm thick coating A on the surface of the pretreated ferritic stainless steel substrate. Then, perform a second thermal spraying of composite powder B to form a 90μm thick coating B on the surface of coating A. After grinding, polishing and cleaning until the total coating thickness is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a gradient coating, followed by low oxygen partial pressure heat treatment at a temperature of 700℃ and an oxygen partial pressure of 5×10⁻⁶. -4 After heat treatment at Pa for 3 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.4 MPa, propane pressure 0.3 MPa, compressed air pressure 0.2 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 80mm, carrier gas pressure 0.6MPa, carrier gas flow rate 50L·min -1 Barrel horizontal velocity 200 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.6 MPa, propane pressure 0.3 MPa, compressed air pressure 0.2 MPa, and powder feeding rate 20 g / min. -1 Spraying distance 150mm, carrier gas pressure 0.8MPa, carrier gas flow rate 50L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 3mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 3% Y. + 62%Y 2+ 35%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 40kV, 80kV, and 100kV, respectively; the cerium ion composition was 3%Ce. + 80% Ce 2+ 17% Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 30 kV, 100 kV, and 120 kV, respectively; the implantation amounts of yttrium and cerium ions were both 3 × 10⁻⁶. 16 / cm 2 The beam current density is 12 μA / cm. 2 ; The preparation steps for DLC thin films are as follows: preheat the substrate to 180°C, and maintain a vacuum level of 5×10⁻⁶. -3After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a 1.0 μm transition layer of Cr was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using hydrogen-diluted acetylene as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.3 Pa. The pulse bias voltage was set to -600 V, the frequency to 60 kHz, and the duty cycle to 40%. After deposition for 2 h, the furnace was cooled.

[0012] Example 4: This example provides a manufacturing process for a special stainless steel, specifically including the following steps: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 75 parts nickel-iron alloy powder, 8 parts cobalt ferrite powder, and 17 parts WC-Cr3C2-Ni; composite powder B includes the following raw materials by mass parts: 48 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a coating A with a thickness of 55μm on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form a coating B with a thickness of 85μm on the surface of coating A. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a gradient coating, followed by low oxygen partial pressure heat treatment at a temperature of 700℃ and an oxygen partial pressure of 5×10⁻⁶. -4 After heat treatment at Pa for 2 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.5 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 100mm, carrier gas pressure 0.65MPa, carrier gas flow rate 60L·min -1 Barrel horizontal velocity 250 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.65 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 5mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 4% Y. + 62%Y 2+ 34%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 45kV, 85kV, and 105kV, respectively; the cerium ion composition was 5%Ce. + 82% Ce 2+ 13%Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 35 kV, 95 kV, and 115 kV, respectively; the implantation amounts of yttrium and cerium ions were both 3.5 × 10⁻⁶. 16 / cm 2 The beam current density is 13 μA / cm. 2 ; The fabrication steps for DLC thin films are as follows: preheat the substrate to 185°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.25 Pa. The pulse bias voltage was set to -650 V, the frequency to 60 kHz, and the duty cycle to 38%. After deposition for 2 h, the furnace was cooled.

[0013] Comparative Example 1: As a control experiment for Example 4, the difference is that thermal spraying of composite powder A was not performed. The specific steps included were as follows: Step 1: Weigh the raw materials according to the mass parts and prepare the composite powder; wherein the composite powder includes the following raw materials by mass parts: 48 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni. Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, thermal spray composite powder is applied to form a coating with a thickness of 85μm. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a single-layer coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a single-layer coating, followed by low oxygen partial pressure heat treatment at a temperature of 700℃ and an oxygen partial pressure of 5×10⁻⁶. -4 After heat treatment at Pa for 2 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for thermal spraying are: oxygen pressure 0.65 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 5mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 4% Y. + 62%Y 2+ 34%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 45kV, 85kV, and 105kV, respectively; the cerium ion composition was 5%Ce. + 82% Ce 2+ 13%Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 35 kV, 95 kV, and 115 kV, respectively; the implantation amounts of yttrium and cerium ions were both 3.5 × 10⁻⁶. 16 / cm 2 The beam current density is 13 μA / cm. 2 ; The fabrication steps for DLC thin films are as follows: preheat the substrate to 185°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.25 Pa. The pulse bias voltage was set to -650 V, the frequency to 60 kHz, and the duty cycle to 38%. After deposition for 2 h, the furnace was cooled.

[0014] Comparative Example 2: As a control experiment for Example 4, the difference is that ion beam implantation and low oxygen partial pressure heat treatment were not performed. Specifically, the following steps were included: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 75 parts nickel-iron alloy powder, 8 parts cobalt ferrite powder, and 17 parts WC-Cr3C2-Ni; composite powder B includes the following raw materials by mass parts: 48 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a coating A with a thickness of 55μm on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form a coating B with a thickness of 85μm on the surface of coating A. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Take a ferritic stainless steel substrate with a gradient coating and perform plasma-enhanced chemical vapor deposition (DLC) thin film to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.5 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 100mm, carrier gas pressure 0.65MPa, carrier gas flow rate 60L·min -1 Barrel horizontal velocity 250 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.65 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 5mm; The fabrication steps for DLC thin films are as follows: preheat the substrate to 185°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.25 Pa. The pulse bias voltage was set to -650 V, the frequency to 60 kHz, and the duty cycle to 38%. After deposition for 2 h, the furnace was cooled.

[0015] Comparative Example 3: As a control experiment for Example 4, the difference is that DLC films were directly deposited without low oxygen partial pressure; specifically, the following steps were included: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 75 parts nickel-iron alloy powder, 8 parts cobalt ferrite powder, and 17 parts WC-Cr3C2-Ni; composite powder B includes the following raw materials by mass parts: 48 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a coating A with a thickness of 55μm on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form a coating B with a thickness of 85μm on the surface of coating A. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Take a ferritic stainless steel substrate with a gradient coating and perform ion beam implantation. Finally, perform plasma-enhanced chemical vapor deposition (DLC) thin film to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.5 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 100mm, carrier gas pressure 0.65MPa, carrier gas flow rate 60L·min -1 Barrel horizontal velocity 250 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.65 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min -1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 5mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 4% Y. + 62%Y 2+ 34%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 45kV, 85kV, and 105kV, respectively; the cerium ion composition was 5%Ce. + 82% Ce 2+ 13%Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 35 kV, 95 kV, and 115 kV, respectively; the implantation amounts of yttrium and cerium ions were both 3.5 × 10⁻⁶. 16 / cm 2 The beam current density is 13 μA / cm. 2 ; The fabrication steps for DLC thin films are as follows: preheat the substrate to 185°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of −100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.25 Pa. The pulse bias voltage was set to -650 V, the frequency to 60 kHz, and the duty cycle to 38%. After deposition for 2 h, the furnace was cooled.

[0016] Comparative Example 4: As a control experiment for Example 4, the difference is that single yttrium ion implantation was used, specifically including the following steps: Step 1: Weigh the raw materials according to the mass parts and prepare composite powder A and composite powder B; wherein composite powder A includes the following raw materials by mass parts: 75 parts nickel-iron alloy powder, 8 parts cobalt ferrite powder, and 17 parts WC-Cr3C2-Ni; composite powder B includes the following raw materials by mass parts: 48 parts nickel-iron alloy powder, 7 parts cobalt ferrite powder, and 45 parts WC-Cr3C2-Ni; Step 2: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form a coating A with a thickness of 55μm on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form a coating B with a thickness of 85μm on the surface of coating A. After grinding, polishing and cleaning until the total thickness of the coating is reduced by 15μm, a ferritic stainless steel substrate with a gradient coating is obtained. Step 3: Ion beam implantation is performed on a ferritic stainless steel substrate with a gradient coating, followed by low oxygen partial pressure heat treatment at a temperature of 700℃ and an oxygen partial pressure of 5×10⁻⁶. -4 After heat treatment at Pa for 2 hours, plasma-enhanced chemical vapor deposition (DLC) thin film was finally performed to obtain stainless steel for magnetic base. The process parameters for a single thermal spraying are: oxygen pressure 0.5 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 100mm, carrier gas pressure 0.65MPa, carrier gas flow rate 60L·min -1 Barrel horizontal velocity 250 mm / s -1 Single-lane horizontal spacing 3mm; The process parameters for secondary thermal spraying are: oxygen pressure 0.65 MPa, propane pressure 0.35 MPa, compressed air pressure 0.3 MPa, and powder feeding rate 25 g / min. -1 Spraying distance 180mm, carrier gas pressure 1.0MPa, carrier gas flow rate 80L·min-1 Barrel horizontal velocity 300 mm / s -1 Single-lane horizontal spacing 5mm; The ion beam implantation process parameters are as follows: using a MEVVA implantation source, the yttrium ion composition is 4% Y. + 62%Y 2+ 34%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 45 kV, 85 kV, and 105 kV, respectively; the yttrium ion implantation amount was 3.5 × 10⁻⁶. 16 / cm 2 The beam current density is 13 μA / cm. 2 ; The fabrication steps for DLC thin films are as follows: preheat the substrate to 185°C, and maintain a vacuum level of 5×10⁻⁶. -3 After plasma etching with Ar-H2 at a 1:1 ratio for 30 min, a transition layer of Cr with a thickness of 0.85 μm was magnetron sputtered through a target material of Cr at a sputtering power of 6 kW and a bias voltage of -100 V. DLC deposition was then performed using acetylene diluted with hydrogen as a precursor, with an acetylene partial pressure of 1.2 Pa and a hydrogen partial pressure of 0.25 Pa. The pulse bias voltage was set to -650 V, the frequency to 60 kHz, and the duty cycle to 38%. After deposition for 2 h, the furnace was cooled.

[0017] Performance testing: 1. Magnetic induction intensity: Magnetic testing was performed in accordance with IEC 60404-4, and the data is recorded in Table 1; 2. Wear resistance test: The CSM reciprocating friction machine was used for friction and wear test. The load was 20N and the frequency was 2Hz. The ball was ground in 3.5wt% sodium chloride solution for 90min. The wear rate was calculated. 3. Corrosion resistance test: In the Shanghai Chenhua CHI760E electrochemical workstation, the open circuit potential test was carried out using 3.5wt% sodium chloride solution as the corrosive medium. The wear rate was calculated after 900s of friction and after 1800s of friction. Table 1

[0018] Conclusion: As can be seen from the above data, the embodiments do not sacrifice the soft magnetic properties of the ferrite, but improve the wear resistance and corrosion resistance of the entire substrate; the comprehensive performance of Embodiment 4 is the most balanced; Comparative Example 1, as a control experiment of Embodiment 4, lacks the transition layer of coating A, resulting in a significant decrease in magnetic induction intensity, and a decrease in wear resistance and corrosion resistance; Comparative Example 2, without ion implantation and low oxygen partial pressure heat treatment, has poor bonding between thermal spraying and DLC film, resulting in a significant decrease in wear resistance and corrosion resistance; Comparative Example 3, although it has ion implantation, lacks subsequent low oxygen partial pressure heat treatment, resulting in uneven diffusion of rare earth ions, poor bonding, and a significant decrease in wear resistance and corrosion resistance; Comparative Example 4, using only single rare earth ion implantation, has lower corrosion resistance than dual rare earth ion implantation.

[0019] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A manufacturing process for a special stainless steel base for magnetic induction, characterized in that, The process includes the following steps: Step 1: After grinding and polishing the ferritic stainless steel substrate, clean and dry it to obtain a pretreated ferritic stainless steel substrate. After preheating, perform a first thermal spraying of composite powder A to form coating A on the surface of the pretreated ferritic stainless steel substrate. Then perform a second thermal spraying of composite powder B to form coating B on the surface of coating A. After grinding, polishing and cleaning, a ferritic stainless steel substrate with a gradient coating is obtained. Step 2: Take a ferritic stainless steel substrate with a gradient coating, perform ion beam implantation, then perform low oxygen partial pressure heat treatment, and finally perform plasma-enhanced chemical vapor deposition (DLC) thin film to obtain stainless steel for magnetic base. The composite powder A comprises the following parts by weight of raw materials: 70-80 parts of nickel-iron alloy powder, 5-10 parts of cobalt ferrite powder, and 10-25 parts of carbide metal powder; the composite powder B comprises the following parts by weight of raw materials: 40-50 parts of nickel-iron alloy powder, 2-7.5 parts of cobalt ferrite powder, and 30-45 parts of carbide metal powder.

2. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The chemical composition of the ferritic stainless steel substrate is as follows (by mass percentage): Cr: 16-18%, C≤0.065%, Si≤0.5%, Mn≤0.6%, Mo≤1.5%, Ni≤0.2%, P≤0.02%, with the balance being Fe and unavoidable impurities.

3. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The carbide metal powder is any one of WC-CoCr, Cr3C2-NiCr, and WC-Cr3C2-Ni; the chemical composition of the nickel-iron alloy powder is: Fe: 16-20%, Cr: 8-10%, Si: 3-5%, Al: 2-3%, and the balance is Ni.

4. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The preheating process parameters are: temperature 120℃, holding time 2h; the primary thermal spraying process parameters are: oxygen pressure 0.4-0.8MPa, propane pressure 0.3-0.4MPa, compressed air pressure 0.2-0.5MPa, powder feeding rate 20-30g·min. -1 Spraying distance: 80-100mm; Carrier gas pressure: 0.6-0.8MPa; Carrier gas flow rate: 50-80L·min -1 Horizontal velocity of the gun barrel: 200-300 mm / s -1 The horizontal spacing between each lane is 2-3mm.

5. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The process parameters for the secondary thermal spraying are: oxygen pressure 0.6-0.8 MPa, propane pressure 0.3-0.5 MPa, compressed air pressure 0.2-0.5 MPa, and powder feeding rate 20-30 g / min. -1 Spraying distance: 150-200mm; Carrier gas pressure: 0.8-1.0MPa; Carrier gas flow rate: 50-80L·min -1 Horizontal velocity of the gun barrel: 300-500 mm / s -1 The horizontal spacing between each lane is 3-5mm.

6. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The process parameters for ion beam implantation are as follows: using a MEVVA implantation source, the yttrium ion composition is 3-5% Y. + 60-64%Y 2+ 32-35%Y 3+ ;Y + Y 2+ Y 3+ The accelerating voltages were 40-50kV, 80-90kV, and 100-120kV, respectively; the cerium ion composition was 3-5%Ce. + 80-85% Ce 2 + 10-17% Ce 3+ Ce + Ce 2+ Ce 3+ The accelerating voltages were 30-40kV, 90-100kV, and 110-120kV, respectively; the implantation amounts of yttrium and cerium ions were both (2-5)×10⁻⁶. 16 / cm 2 The beam current density is 12-15 μA / cm. 2 .

7. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The process parameters for the low oxygen partial pressure heat treatment are: temperature 600-700℃, oxygen partial pressure (1-5)×10⁻⁶. -4 Pa, heat treatment time is 2-3h.

8. The manufacturing process of a special stainless steel for a magnetic base according to claim 1, characterized in that, The thickness of coating A is 50-60 μm, and the thickness of coating B is 80-90 μm; Polishing until the total thickness is reduced by 15-20 μm; the preparation steps of the DLC film are as follows: preheating the substrate to 180-200℃, with a vacuum degree of 5×10 -3 After plasma etching for 20-40 minutes, a transition layer of Cr with a thickness of 0.8-1.0 μm was magnetron sputtered, followed by DLC deposition using hydrogen-diluted acetylene as a precursor. The partial pressure of acetylene was 0.8-1.2 Pa, and the partial pressure of hydrogen was 0.1-0.3 Pa. The pulse bias voltage was set to -600~-800V, the frequency was 40-60kHz, and the duty cycle was 30-40%. After deposition for 2-3 hours, the furnace was cooled.

9. A special stainless steel for magnetic bases, characterized in that, Prepared by the manufacturing process according to any one of claims 1-8.

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