Thin silicon steel sheet with low-magnetism metal compound infiltrated layer and preparation method and application of thin silicon steel sheet

Abstract

The invention discloses a thin silicon steel sheet with a low-magnetism metallic compound infiltrated layer and a preparation method and application thereof.The thin silicon steel sheet with the low-magnetism metallic compound infiltrated layer is characterized in that cold-rolled non-oriented silicon steel with the silicon content of 3.2-3.4 wt% serves as a base body, and the metallic compound infiltrated layer which is evenly distributed and is 10-30 micrometers in thickness is formed on the surface of the base body; the thickness of the thin silicon steel sheet is 0.2 to 0.35 mm; the metal compound infiltrated layer is a mutual diffusion layer of a metal compound and iron, and the metal compound is pure Cr or Fe3Ni; and the saturation magnetization of the thin silicon steel sheet with the low-magnetism metal compound infiltrated layer is 170-210 emu / g. The infiltrated layer obtained through the method is firmly combined with the base body, the magnetic loss of the non-oriented silicon steel can be remarkably reduced, and the problems that due to the magnetic bridge effect of traditional silicon steel, power consumption of a motor is increased, and working efficiency is reduced are effectively solved.

Description

Technical Field

[0001] This invention relates to the application of metallic materials, specifically to a metal compound diffusion layer technology for reducing the magnetism of thin silicon steel sheets used in magnetic bridges. Background Technology

[0002] In traditional motor structures, the magnetic bridge, as a special structure at the edge of the pole pieces, functions primarily to resist the effects of high-speed centrifugal force on the permanent magnet through mechanical strength design. In traditional designs, to meet mechanical stability requirements, the magnetic bridge needs to maintain a specific thickness. However, this structure forms a closed magnetic loop during magnetic circuit conduction, generating a leakage flux effect coupled with the main magnetic field, directly impacting the motor's energy conversion efficiency. In engineering practice, there is a contradictory balance in the design of the magnetic bridge thickness: from a magnetic perspective, the thickness needs to be minimized to reduce leakage flux, while mechanical strength requirements necessitate maintaining the basic thickness. Summary of the Invention

[0003] This invention provides an innovative method for preparing a low-magnetic metal compound diffusion layer on a thin silicon steel sheet, aiming to solve the problems of increased power consumption and decreased working efficiency of motors caused by the magnetic bridge effect in traditional silicon steel.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: A thin silicon steel sheet with a low-magnetic metal compound infiltration layer is disclosed. The thin silicon steel sheet with a low-magnetic metal compound infiltration layer uses cold-rolled non-oriented silicon steel with a silicon content of 3.2-3.4 wt% as the substrate, and forms a uniformly distributed metal compound infiltration layer with a thickness of 10-40 micrometers on its surface. The thickness of the thin silicon steel sheet is 0.2-0.35 mm. The metal compound infiltration layer is an interdiffusion layer of metal compound and iron, and the metal compound is pure Cr or FeNi3. The saturation magnetization of the thin silicon steel sheet with the low-magnetic metal compound infiltration layer is 170-210 emu / g.

[0005] To achieve better magnetic bridge performance, in some embodiments, preferably, the aforementioned metal compound diffusion layer is distributed on both sides of the silicon steel substrate.

[0006] The present invention also provides a method for preparing the above-mentioned thin silicon steel sheet with a low magnetic metal compound diffusion layer, the method comprising the following steps: (1) Sample pretreatment: The surface of the thin silicon steel sheet was ground and polished, and then ultrasonically cleaned with acetone and anhydrous ethanol; (2) Annealing and activation: The treated silicon steel sheets are annealed at high temperature and cooled in the furnace; (3) Furnace loading: The activated silicon steel sheet and metal target are placed in the vacuum chamber and surrounded by a heat insulation barrier. The silicon steel sheet and metal target are connected to two different cathodes respectively. The metal target is a Ni target or a Cr target. (4) Sputtering treatment: Argon gas is introduced and the voltages of the two cathodes are turned on at the same time. The gas pressure inside the furnace is adjusted, and the cathode voltage and sputtering temperature are adjusted to perform dual-cathode sputtering.

[0007] When a double-surface diffusion layer treatment of silicon steel substrate is required, after the sputtering treatment in step (4) is completed, the silicon steel sheet is flipped over and the sputtering treatment in step (4) is performed again.

[0008] This invention employs vacuum plasma surface metallurgy technology, achieving a dual technological breakthrough by constructing a 10-30 μm-scale metal compound diffusion layer in the magnetic bridge region of a silicon steel substrate. This diffusion layer exhibits precise thickness control and elemental gradient distribution characteristics: on the one hand, it enhances the mechanical load-bearing capacity of the magnetic bridge through metallurgical strengthening, allowing for a reduction in structural thickness while maintaining the same strength; on the other hand, it induces the formation of a modified layer in the magnetic bridge region that reduces saturation magnetization by 20-25%, effectively attenuating magnetic flux density. This synergistic effect not only overcomes the thickness limitations of traditional magnetic bridge designs but also significantly suppresses magnetic leakage through magnetic performance optimization, ultimately resulting in a significant improvement in the working efficiency of the silicon steel motor wafer.

[0009] Furthermore, the specific method for preparing the thin silicon steel sheet with a low-magnetic metal compound infiltration layer of the present invention is as follows: (1) Sample pretreatment: The surface of the thin silicon steel sheet was sanded and polished with sandpaper, and then ultrasonically cleaned with acetone and anhydrous ethanol; (2) Annealing and activation: The treated silicon steel sheets are annealed at 950℃-1050℃ for 5-10 minutes and then cooled in the furnace. (3) Furnace loading: The activated silicon steel sheet and metal target are placed in the vacuum chamber and surrounded by a heat insulation barrier. The silicon steel sheet and metal target are connected to two different cathodes respectively. The substrate and the target do not contact each other. The electrode spacing is controlled at 20-30mm. The metal target is Ni target or Cr target. (4) Sputtering treatment: Argon gas is introduced and the voltages of the two cathodes are turned on at the same time. The gas pressure inside the furnace is adjusted, and the cathode voltage and sputtering temperature are adjusted to perform dual-cathode sputtering.

[0010] During sputtering, the furnace pressure is controlled at 20-40 Pa, the argon flow rate is controlled at 40-50 sccm, the substrate voltage and target voltage are controlled at 200-1000 V (preferably the substrate voltage is 850-900℃), and the substrate voltage is less than the target voltage, with the voltage difference controlled at 200-300 V; the sputtering temperature is controlled at 500-950℃ (preferably 850-900℃), and the sputtering time is 4-5 h.

[0011] The present invention also provides the application of the above-mentioned thin silicon steel sheet in magnetic bridges.

[0012] The present invention has the following advantages over the prior art: 1. Significant optimization of magnetic properties: By forming a 10~30μm layer of metal compounds such as Cr and Ni3Fe on the surface of silicon steel through dual cathode sputtering, the saturation magnetization of non-oriented silicon steel is reduced by 15%~25%, effectively suppressing leakage magnetic loss caused by magnetic bridge effect and improving the energy conversion efficiency of motor.

[0013] 2. Strong process controllability and uniform and dense infiltration layer: The dual cathode potential difference assisted heating and magnetron sputtering are coordinated and controlled, combined with a cylindrical mesh insulation barrier device. By precisely controlling the sputtering power, substrate temperature, electrode spacing (20~30 mm) and voltage difference (200~300 V), the composition of the infiltration layer is uniform, the structure is dense, and the bonding with the substrate is firm, forming a directional metal compound infiltration layer.

[0014] 3. High process stability: The process adopts step-by-step control (pretreatment → annealing and activation → dual cathode sputtering → alloy diffusion layer formation), which can be precisely controlled by adjusting process parameters. It has good repeatability and is suitable for batch surface modification treatment of silicon steel sheets for high-efficiency motors. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the apparatus for preparing thin silicon steel sheets with low magnetic metal compound infiltration layer according to the present invention; in the figure, 1-target material, 2-substrate, 3-thermal insulation barrier, 4-substrate electrode, 5-target material electrode; Figure 2 The metal compound diffusion layer in the sample prepared in Example 1 of the present invention is shown in Figure a, which is a schematic diagram of the diffusion layer thickness in the Ni diffusion section, and Figure b is the elemental distribution curve of the section. Figure 3 The metal compound infiltration layer in the sample prepared in Example 2 of the present invention is shown in Figure c, which is a schematic diagram of the thickness of the infiltrated layer in the Cr cross section, and d is the elemental distribution curve of the cross section. Figure 4 For the analysis of the surface compound composition of the samples prepared in this invention, e is the surface compound composition of the Cr-diffused sample prepared in Example 1, and f is the surface compound composition of the Ni-diffused sample prepared in Example 2; Figure 5 The first part shows the saturation magnetization curve of the sample prepared according to the present invention, g is the saturation magnetization curve of the Cr-infiltrated sample prepared in Example 1, and h is the saturation magnetization curve of the Ni-infiltrated sample prepared in Example 2. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0017] Example 1. Nickel diffusion onto the surface of thin-gauge silicon steel using vacuum plasma technology. like Figure 1 As shown, the preparation method of the present invention includes the following steps: Step 1: Grind the surface of the 0.35mm thick silicon steel sheet to be plated with 400-2000 grit sandpaper, then polish the surface with W2.5 diamond polishing paste. Next, ultrasonically clean it with acetone and anhydrous ethanol for 15 minutes in sequence, and finally dry it with cool air at 25 ℃ for later use.

[0018] Step 2: The treated silicon steel sheet is held at 950℃ for 5 minutes (5-10 minutes is acceptable) for high-temperature annealing, and then cooled in the furnace.

[0019] Step 3: Clean the furnace inner wall, tooling structure and Ni target 1; then place the silicon steel sheet substrate 2 at the cathode end and the Ni target at the source end, adjust the distance between the two electrodes to 25mm; and set up a cylindrical mesh insulation barrier 3 inside the furnace.

[0020] Step 4: Close the furnace door, turn on the mechanical pump, open the pre-evacuation valve, and when the gas pressure inside the furnace drops below 10 Pa, run the molecular pump to control the vacuum level inside the furnace. Within.

[0021] Step 5: Continuously introduce Ar gas, control the working gas pressure at 30 Pa; set the gas flow rate to 40 sccm.

[0022] Step 6: Adjust the voltage of the substrate electrode 4 to 600V and the voltage of the target electrode 5 to 850V to raise the temperature. The workpiece surface temperature should reach 850℃ and be held for 4 hours to ensure adequate heat. The interdiffusion layer grows uniformly.

[0023] Step 7: After the heat preservation is completed, the source and cathode voltages are reduced sequentially, and the sample is taken out after cooling for 4 hours to obtain a Ni infiltration layer with concentration gradient characteristics.

[0024] like Figure 2 As shown in Figure a, the infiltrated layer exhibits an interdiffusion layer structure with a thickness of 37 μm, and there is a good bonding transition layer between it and the substrate.

[0025] like Figure 2 Figure b shows the elemental distribution curves of Si, Ni, and Fe in the cross-section of the infiltrated layer. It can be seen from the figure that silicon is relatively uniform and stable in the sample; the strength of nickel shows significant peaks in the ranges of approximately 10-30 µm and 60-80 µm, indicating that nickel diffuses in the sample due to its thickness; the strength of iron reaches its peak in the range of approximately 40-60 µm, indicating that iron is concentrated in this range.

[0026] like Figure 4 As shown in f, the surface spectrum of the nickel-diluent sample has strong peaks near 43°, 50°, and 74° and no other obvious impurity peaks, indicating that the main component of the diluent layer is Ni3Fe.

[0027] Example 2. Chromium infiltration onto the surface of thin-gauge silicon steel using vacuum plasma technology. The preparation method includes the following steps: Step 1: Pre-treatment of silicon steel workpiece: The surface of the 0.2mm thick silicon steel sheet to be plated is polished with 400~2000 grit sandpaper in sequence; polished to mirror finish with W2.5 diamond polishing paste to eliminate micro-defects; ultrasonically cleaned with acetone and anhydrous ethanol for 20 minutes respectively to remove grease and particle residue; dried with cool air at 25℃ and then vacuum stored.

[0028] Step 2: Annealing and activation: The treated silicon steel sheet is annealed at 1050℃ for 10 minutes and then cooled in the furnace.

[0029] Step 3: Equipment cleaning and workpiece installation: Wipe the furnace inner wall, tooling fixtures and Cr target material (purity ≥99.95%) with anhydrous ethanol; place the silicon steel sheet substrate at the cathode end and the Cr target material at the source end, adjust the electrode spacing to 30 mm, and optimize the plasma distribution.

[0030] Step 4: Establish a vacuum environment: Close the furnace door and start the mechanical pump to pre-evacuate until the furnace pressure is <10Pa; then start the molecular pump to stabilize the vacuum level. .

[0031] Step 5: Introduce argon gas as a protective gas. The Ar gas parameters are set as follows: flow rate in the range of 50 sccm (to maintain the dynamic balance between sputtering and anti-sputtering); working pressure is adjusted to 38 Pa (to optimize the synergistic relationship between plasma density and deposition rate).

[0032] Step 6: Prepare the Cr-Fe interdiffusion layer. The substrate voltage is gradually increased to 800V to excite the sputtering of the Cr target; the cathode voltage is adjusted to 1000V to maintain the substrate temperature at 900℃; the holding time is 5 h to promote Cr-Fe interdiffusion.

[0033] like Figure 3 As shown in c and 3d, the infiltrated layer is uniformly distributed in the matrix, with a thickness of 17 μm and a dense structure.

[0034] like Figure 4 Figure e shows the surface compound composition of the sample obtained by Cr infiltration. As can be seen from the figure, obvious diffraction peaks appear near 2θ ≈ 44°, 65°, and 82°, indicating that a crystalline Cr metal layer has been successfully infiltrated and formed on the sample surface. The surface is dominated by the pure Cr phase.

[0035] Example 1 Double-layer Ni-infiltrated (Double Ni) and double-layer Cr-infiltrated (Double Cr) samples were prepared according to the preparation processes in Examples 1 and 2. These samples, along with the single-layer Ni-infiltrated (Single Ni) and single-layer Cr-infiltrated (Single Cr) samples prepared in Examples 1 and 2, were compared with the silicon steel substrate. Figure 5 Medium nickel penetration ( Figure 5 g) and chromium plating ( Figure 5 The hysteresis loops (h) revealed that the saturation magnetization of the sample material with the metal compound infiltration layer was lower than that of the silicon steel substrate (Figure: Si Steel curve), and the saturation magnetization of the sample material with the double metal compound infiltration layer was even lower.

[0036] Furthermore, compared to the saturation magnetization, the double-layer nickel infiltration is more effective in reducing the saturation magnetization: from 203 emu / g of the substrate to 170 emu / g.

Claims

1. A thin silicon steel sheet with a low-magnetic metal compound infiltration layer, characterized in that, The thin silicon steel sheet with a low magnetic metal compound infiltration layer uses cold-rolled non-oriented silicon steel with a silicon content of 3.2-3.4 wt% as the substrate, and forms a uniformly distributed metal compound infiltration layer with a thickness of 10-40 micrometers on its surface; the thickness of the thin silicon steel sheet is 0.2-0.35 mm; the metal compound infiltration layer is an interdiffusion layer of metal compound and iron, and the metal compound is pure Cr or Fe3Ni; the saturation magnetization of the thin silicon steel sheet with the low magnetic metal compound infiltration layer is 170-210 emu / g.

2. The thin silicon steel sheet with a low-magnetic metal compound infiltration layer according to claim 1, characterized in that, The metal compound diffusion layer is distributed on both sides of the silicon steel substrate.

3. The method for preparing the thin silicon steel sheet with a low-magnetic metal compound infiltration layer as described in claim 1, characterized in that, The preparation method includes the following steps: (1) Sample pretreatment: The surface of the thin silicon steel sheet was ground and polished, and then ultrasonically cleaned with acetone and anhydrous ethanol; (2) Annealing and activation: The treated silicon steel sheet is annealed at high temperature at 950-1200℃ for 10-15 minutes and then cooled in the furnace. (3) Furnace loading: The activated silicon steel sheet and metal target are placed in the vacuum chamber and surrounded by a heat insulation barrier. The silicon steel sheet and metal target are connected to two different cathodes respectively. The metal target is a Ni target or a Cr target. (4) Sputtering treatment: Argon gas is introduced and the voltages of the two cathodes are turned on at the same time. The gas pressure inside the furnace is adjusted, and the cathode voltage and sputtering temperature are adjusted to perform dual-cathode sputtering.

4. The preparation method according to claim 3, further comprising: (5) After flipping the silicon steel sheet, repeat step (4) for another sputtering process.

5. The preparation method according to claim 4, characterized in that, In step (4), during sputtering, the furnace pressure is controlled at 20-40 Pa, the argon flow rate is controlled at 40-50 sccm, the substrate voltage and target voltage are controlled at 200-1000 V, and the substrate voltage is less than the target voltage, with the voltage difference controlled at 200-300 V; the sputtering temperature is controlled at 500-950℃, and the sputtering time is 4-5 h.

6. The preparation method according to claim 5, characterized in that, The base voltage is controlled at 600-800V.

7. The preparation method according to claim 6, characterized in that, The sputtering temperature is controlled at 850-900℃.

8. The preparation method according to claim 7, characterized in that, In step (2), the annealing temperature is 950℃-1050℃, and the holding time is 5-10 minutes.

9. The preparation method according to claim 8, characterized in that, In step (3), the thermal insulation barrier is made of 304 stainless steel and has a cylindrical mesh structure; in step (3), the spacing between the silicon steel sheet and the metal target is controlled at 20-30mm.

10. The application of the thin silicon steel sheet as described in claim 1 or 2 in a magnetic bridge.

Images