Non-oriented silicon steel composite material and preparation method thereof

Abstract

The invention discloses a non-oriented silicon steel composite material and a preparation method thereof. The preparation method comprises the steps that pretreated non-oriented silicon steel is obtained; depositing an oxide template layer on the surface of the pretreated non-oriented silicon steel; depositing a magnetic insulator layer on the surface of the oxide template layer to obtain a first preset silicon steel composite material; the first preset silicon steel composite material is subjected to heat treatment; and depositing a compact layer on the surface of the magnetic insulator layer to obtain a second preset silicon steel composite material, and carrying out heat treatment on the second preset silicon steel composite material to obtain the non-oriented silicon steel composite material. According to the method, through collaborative design of the oxide template layer and the magnetic insulator layer, high orientation and high density of the magnetic insulator layer on the silicon steel substrate are achieved, and therefore the insulation resistivity and the eddy current resistance are effectively improved. The preparation method not only ensures comprehensive optimization of the electromagnetic performance, heat resistance and adhesive force of the magnetic insulator layer, but also has relatively high industrial application value and popularization prospect.

Description

Technical Field

[0001] This application relates to the field of silicon steel technology, specifically to a non-oriented silicon steel composite material and its preparation method. Background Technology

[0002] Non-oriented silicon steel is an important soft magnetic material widely used in the manufacture of cores for electromagnetic equipment such as motors, generators, and transformers. Non-oriented silicon steel is typically laminated in thin sheets to form the core of a motor or generator. Direct metal-to-metal contact between the sheets would create a conductive path; therefore, surface insulation treatment of non-oriented silicon steel can effectively block inter-sheet currents and suppress eddy currents, thereby reducing iron losses.

[0003] In existing technologies, insulation is generally achieved by coating the surface of non-oriented silicon steel with an insulating coating. For example, a nickel-based composite coating can be formed on the steel surface through electroplating using an electroplating solution containing nickel sulfate and SiO2 colloidal particles. While this method can improve the surface resistivity and insulation performance of non-oriented silicon steel to some extent, it suffers from complex processes, parameter sensitivity, poor film thickness uniformity leading to increased local leakage current or magnetic loss, and insufficient film-substrate interface adhesion, making it prone to peeling or cracking under thermomechanical loads. Furthermore, existing technologies also utilize a chemiluminescent sol-gel process to prepare oxide insulating films on silicon steel surfaces. By forming a Zr-SiO2 composite film layer on the silicon steel surface, it effectively improves material adhesion and long-term stability. However, this method is limited by complex process requirements and strict substrate pretreatment requirements, making large-scale continuous production difficult.

[0004] Therefore, there is an urgent need for a simple, easy-to-control preparation method suitable for large-scale production to improve the iron loss, resistivity, adhesion and insulation performance of the insulating layer on the surface of silicon steel. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a technical solution for a non-oriented silicon steel composite material and its preparation method, as described below: On one hand, embodiments of this application provide a method for preparing a non-oriented silicon steel composite material, the method comprising: Obtain pretreated non-oriented silicon steel; An oxide template layer is deposited on the surface of the pretreated non-oriented silicon steel. A magnetic insulating layer is deposited on the surface of the oxide template layer to obtain a first preset silicon steel composite material; The first preset silicon steel composite material is heat-treated; A dense layer is deposited on the surface of the magnetic insulator layer to obtain a second preset silicon steel composite material. The second preset silicon steel composite material is then heat-treated to obtain a non-oriented silicon steel composite material.

[0006] In one possible implementation, the oxide template layer includes a first oxide template layer and a homogeneous oxide buffer layer; the deposition of the oxide template layer on the surface of the pretreated non-oriented silicon steel includes: The first oxide template layer is deposited on the surface of the pretreated non-oriented silicon steel; the full width at half maximum (FWHM) of the first oxide template layer is ≤6°. The homogeneous oxide buffer layer is deposited on the surface of the first oxide template layer.

[0007] In one possible implementation, the deposition method of the first oxide template layer includes ion beam assisted deposition, and the process conditions for depositing the first oxide template layer satisfy at least one of the following characteristics: The ion energy is 800 eV–1000 eV; Ion incident angle 35°–45°; Ion / evaporation beam flux ratio: 0.3–0.6; The temperature of the pretreated non-oriented silicon steel is controlled at 250℃–320℃.

[0008] In one possible implementation, the oxide template layer satisfies at least one of the following characteristics: The total thickness of the oxide template layer is 70 nm–170 nm; The materials of the first oxide template layer and the homogeneous oxide buffer layer are magnesium oxide; The thickness of the first oxide template layer is 20 nm–50 nm; The thickness of the homogeneous oxide buffer layer is 50–120 nm.

[0009] In one possible implementation, after obtaining the pretreated non-oriented silicon steel, the method further includes: A diffusion barrier layer is deposited on the surface of the pretreated non-oriented silicon steel; the material of the diffusion barrier layer is either Al2O3 or Si3N4; the thickness of the diffusion barrier layer is 5nm-15nm. The deposition of an oxide template layer on the surface of the pretreated non-oriented silicon steel includes: The oxide template layer is deposited on the surface of the diffusion barrier layer.

[0010] In one possible implementation, the deposition of a magnetic insulating layer on the surface of the oxide template layer to obtain a first predetermined silicon steel composite material includes: A magnetic insulating layer is deposited on the surface of the oxide template layer using pulsed laser deposition or radio frequency magnetron sputtering. The magnetic insulating layer satisfies at least one of the following characteristics: The material of the magnetic insulating layer is Ni. 1-x Zn x Fe2O4, where 0.3≤x≤0.7; The thickness of the magnetic insulating layer is 100nm–500nm.

[0011] In one possible implementation, the process conditions for depositing the magnetic insulating layer satisfy at least one of the following characteristics: The deposition temperature is 500℃–650℃; The energy density is 1.0 J / cm²–2.0 J / cm²; The deposition rate was 0.05 nm / s–0.20 nm / s; The partial pressure of oxygen is 0.5 Pa–3 Pa.

[0012] In one possible implementation, obtaining the pretreated non-oriented silicon steel includes: Obtain initial non-oriented silicon steel; the chemical composition of the initial non-oriented silicon steel by weight percentage is: Si: 2.5 wt.%~4.5 wt.%, Mn: 0.1 wt.%~0.2 wt.%, C: 0.005 wt.%, Al: 0.5 wt.%~1.0 wt.%, S: 0.001 wt.%~0.002 wt.%, with the remainder being Fe and unavoidable impurities; The initial non-oriented silicon steel is cleaned to obtain the pretreated non-oriented silicon steel; the surface roughness of the pretreated non-oriented silicon steel is ≤10nm; the cleaning method includes ion bombardment cleaning.

[0013] In one possible implementation, the dense layer satisfies at least one of the following characteristics: The thickness of the dense layer is 10 nm–50 nm; The material of the dense layer is either SiNx or Al2O3.

[0014] On the other hand, this application also provides a non-oriented silicon steel composite material, which is prepared by the above-described method for preparing non-oriented silicon steel composite materials; the non-oriented silicon steel composite material comprises: Pretreated non-oriented silicon steel; An oxide template layer located on the surface of the non-oriented silicon steel; A magnetic insulating layer located on the surface of the oxide template layer; A dense layer located within the magnetic insulator layer.

[0015] In one possible implementation, the oxide template layer includes a first oxide template layer and a homogeneous oxide buffer layer, wherein the first oxide template layer is located on the surface of the pretreated non-oriented silicon steel, and the homogeneous oxide buffer layer is located on the surface of the first oxide template layer; wherein the first oxide template layer is prepared by an ion beam assisted deposition process.

[0016] In one possible implementation, the non-oriented silicon steel composite material further includes a diffusion barrier layer located between the pretreated non-oriented silicon steel and the oxide template layer.

[0017] The non-oriented silicon steel composite material and its preparation method provided in this application have the following technical effects: This application discloses a non-oriented silicon steel composite material and its preparation method. The preparation method includes obtaining pretreated non-oriented silicon steel; depositing an oxide template layer on the surface of the pretreated non-oriented silicon steel; depositing a magnetic insulator layer on the surface of the oxide template layer to obtain a first pre-designed silicon steel composite material; heat-treating the first pre-designed silicon steel composite material; depositing a dense layer on the surface of the magnetic insulator layer to obtain a second pre-designed silicon steel composite material; and heat-treating the second pre-designed silicon steel composite material to obtain the non-oriented silicon steel composite material. The above method deposits an oxide template layer and a magnetic insulator layer on the surface of the pretreated non-oriented silicon steel, and prepares a sealing layer on the surface of the magnetic insulator layer. Through this synergistic design of the oxide template layer and the magnetic insulator layer, the magnetic insulator layer achieves high orientation and high density on the silicon steel matrix, thereby effectively improving the insulation resistivity and anti-eddy current performance. Furthermore, the rapid thermal annealing process avoids matrix grain coarsening and magnetic property degradation, ensuring overall mechanical stability. Furthermore, introducing a dense layer on the surface of the magnetic insulator layer can enhance the surface compactness of the insulator layer, avoid matrix grain coarsening and magnetic property degradation, and ensure overall mechanical stability. This preparation method not only ensures comprehensive optimization of the film layer in terms of electromagnetic properties, heat resistance, and adhesion, but also is compatible with roll-to-roll continuous production, and has high industrial application value and promising prospects for promotion. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic flowchart of a method for preparing a non-oriented silicon steel composite material according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the structure of a non-oriented silicon steel composite material provided in the embodiments of this application. Figure 1 .

[0021] Figure 3 This is a schematic diagram of the structure of a non-oriented silicon steel composite material provided in the embodiments of this application. Figure 2 .

[0022] Figure 4 This is a schematic diagram of the structure of a non-oriented silicon steel composite material provided in the embodiments of this application. Figure 3 .

[0023] The following are Figures 2-4 The reference numerals in the attached figures are explained as follows: 1-Pretreated non-oriented silicon steel; 2-Oxide template layer; 21-First oxide template layer; 22-Homogeneous oxide buffer layer; 3-Magnetic insulator layer; 4-Dense layer; 5-Diffusion barrier layer. Detailed Implementation

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

[0025] It should be noted that, in the description of this application, the following definitions shall apply unless a different definition is given elsewhere in the claims or this specification. All numerical values, whether or not explicitly indicated, are defined herein as being modified by the term "about". The term "about" generally refers to a range of numerical values ​​that a person skilled in the art would consider equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A range of numerical values ​​indicated by a low value and a high value is defined as including all numerical values ​​within that range and all subranges included within that range.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0027] It should be noted that, in the description of this application, the terms "on," "above," "over," and "above" should be interpreted in the broadest sense, meaning that a description containing these terms is interpreted as "a component may be disposed on another component in direct contact, or there may be an intermediate component or layer between the components." Furthermore, for ease of description, this application may also use spatial relative terms such as "below," "under," "below," "on," "above," "lower," and "upper" to describe the relationship between one element or component and another element or component shown in the accompanying drawings. In addition to the orientations described in the figures, spatial relative terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90° or otherwise), and the spatial relative descriptive terms used in this application can be interpreted accordingly.

[0028] As used in this application, the term "layer" refers to a portion of material comprising a region of a certain thickness. A layer may extend over the entire lower or upper structure, or it may extend within a localized area of ​​the lower or upper structure. Furthermore, a layer may be a region of a homogeneous or heterogeneous continuous structure with a thickness less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure, or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically, and / or along a conical surface. A single layer may comprise multiple layers.

[0029] on the one hand, Figure 1 A schematic flowchart illustrating a method for preparing a non-oriented silicon steel composite material, as provided in this application embodiment, is shown below. Figure 1 As shown, the preparation method includes the following steps: S1: Obtain pretreated non-oriented silicon steel 1; S3: Deposit an oxide template layer 2 on the surface of the pretreated non-oriented silicon steel 1; S5: Deposit a magnetic insulating layer 3 on the surface of the oxide template layer 2 to obtain a first preset silicon steel composite material; S7: Perform heat treatment on the first preset silicon steel composite material; S9: A dense layer 4 is deposited on the surface of the magnetic insulator layer 3 to obtain a second preset silicon steel composite material. The second preset silicon steel composite material is then heat-treated to obtain a non-oriented silicon steel composite material.

[0030] In this embodiment, non-oriented electrical steel (NOES) is an important soft magnetic material widely used in the core manufacturing of electromagnetic equipment such as motors, generators, and transformers. Its "non-oriented" nature refers to the absence of a specific preferred orientation of the grains during rolling (as opposed to oriented silicon steel), thus resulting in relatively uniform magnetic properties in all directions. Pre-treated non-oriented silicon steel 1 refers to non-oriented silicon steel whose surface has undergone pre-treatment, including but not limited to surface cleaning, activation, and deburring. The purpose of pre-treatment is to remove impurities from the surface of the non-oriented silicon steel and to control its surface roughness.

[0031] In step S3 above, the oxide template layer 2 is a functional oxide thin layer that uses an oxide thin film as a template for subsequent epitaxy, deposition, or etching. Specifically, it guides or controls subsequent thin film growth, crystal orientation, interface structure, or device performance. Specifically, the oxide template layer 2 serves as a functional oxide thin film guiding the growth of the magnetic insulator layer 3. Optionally, the material of the oxide template layer 2 can be magnesium oxide, aluminum oxide, lanthanum aluminate, strontium titanate, etc., and can be selected adaptively based on the material of the upper magnetic insulator layer 3.

[0032] In step S5 above, the magnetic insulating layer 3 is obtained by depositing a magnetic insulating material on the surface of an oxide thin film layer. The magnetic insulating material is a type of functional material that simultaneously maintains long-range magnetic order and macroscopic electrical insulation. Optionally, the deposition method includes, but is not limited to, physical vapor deposition (PVD) and chemical vapor deposition (CVD). Specifically, it can be pulsed laser deposition (PLD), magnetron sputtering, atmospheric pressure CVD, low-pressure CVD, etc. The specific method can be selected based on the material of the magnetic insulating layer 3.

[0033] Here, the composite structure obtained in step S5, which includes pretreated non-oriented silicon steel 1, oxide template layer 2 and magnetic insulator layer 3, is named the first preset silicon steel composite material.

[0034] In step S7 above, the first preset silicon steel composite material is heat-treated to achieve crystal rearrangement and defect self-healing of the first preset silicon steel composite material. Optionally, the heat treatment can be carried out by rapid thermal annealing (RTA), with a heating rate ≥30℃ / s, holding at 700–780℃ for 10–20 min, a cooling rate ≥10℃ / s, and an annealing atmosphere of O2 / Ar mixed atmosphere.

[0035] Optionally, rapid thermal annealing (RTA) employs a dual-zone infrared heating system, with temperature uniformity controlled within ±3°C to prevent substrate warping and film cracking. Dual-zone heating solves the wafer temperature non-uniformity problem present in traditional single-zone heating systems, thereby achieving more precise, uniform, and repeatable heat treatment, while infrared heating provides rapid heating and precise control.

[0036] In step S9 above, after annealing, a dense layer 4 is deposited on the surface of the magnetic insulator layer 3. The function of the dense layer 4 is to improve the surface density of the magnetic insulator layer 3 on the surface of the non-oriented silicon steel. After preparing the dense layer 4, the obtained second pre-designed silicon steel composite material is heat-treated to release residual stress in the composite material and improve the interfacial bonding strength. Thus, the following is obtained: Figure 2 The non-oriented silicon steel composite material shown consists of, from bottom to top, pretreated non-oriented silicon steel 1, oxide template layer 2, magnetic insulator layer 3, and dense layer 4. Optionally, the dense layer 4 can also be called a sealing layer, used to reduce the porosity of the magnetic insulator layer 3, thereby improving the density of the magnetic insulator layer 3.

[0037] Optionally, the heat treatment in step S9 can be carried out by baking, with a baking temperature of 80-160℃, preferably 100℃, and a baking time of 0.5-3h, preferably 1h.

[0038] Thus, in this embodiment, an oxide template layer 2 and a magnetic insulator layer 3 are deposited on the surface of a pretreated non-oriented silicon steel 1, and a sealing layer is prepared on the surface of the magnetic insulator layer 3. Through this synergistic design of the oxide template layer and the magnetic insulator layer 3, the magnetic insulator layer 3 achieves high orientation and high density on the silicon steel substrate, thereby effectively improving insulation resistivity and eddy current resistance. Furthermore, a rapid thermal annealing process avoids substrate grain coarsening and magnetic property degradation, ensuring overall mechanical stability. The introduction of a dense layer 4 on the surface of the magnetic insulator layer 3 enhances the surface density of the insulator layer, preventing substrate grain coarsening and magnetic property degradation, and ensuring overall mechanical stability. This preparation method not only ensures comprehensive optimization of the film layer in terms of electromagnetic properties, heat resistance, and adhesion, but also allows for continuous roll-to-roll production, possessing high industrial application value and promising prospects.

[0039] In one feasible implementation, this application embodiment also provides a pretreatment method for non-oriented silicon steel. In step S1 above, obtaining the pretreated non-oriented silicon steel 1 includes: Obtain initial non-oriented silicon steel; the chemical composition of the initial non-oriented silicon steel by weight percentage is: Si: 2.5 wt.%~4.5 wt.%, Mn: 0.1 wt.%~0.2 wt.%, C: 0.005 wt.%, Al: 0.5 wt.%~1.0 wt.%, S: 0.001 wt.%~0.002 wt.%, with the remainder being Fe and unavoidable impurities; The initial non-oriented silicon steel is cleaned to obtain the pretreated non-oriented silicon steel 1; the surface roughness of the pretreated non-oriented silicon steel 1 is ≤10nm; the cleaning method includes ion bombardment cleaning.

[0040] In this embodiment, the pretreatment involves cleaning the initial non-oriented silicon steel. The surface roughness of the pretreated non-oriented silicon steel 1 is ≤10 nm. The cleaning methods include, but are not limited to, ion bombardment cleaning and acid pickling. When ion bombardment cleaning is used, argon ion bombardment can be used to clean the surface of the initial non-oriented silicon steel for 10–15 min to remove the oxide film and residual contaminant layer, and the surface roughness is controlled to Ra≤10 nm.

[0041] Optionally, the preparation method described in the embodiments of this application is applicable to non-oriented silicon steel sheets with a thickness of 0.1-0.6 mm.

[0042] In one feasible embodiment, the oxide template layer 2 includes a first oxide template layer 21 and a homogeneous oxide buffer layer 22; in step S3 above, depositing the oxide template layer 2 on the surface of the pretreated non-oriented silicon steel 1 includes: S31: Deposit the first oxide template layer 21 on the surface of the pretreated non-oriented silicon steel 1; the full width at half maximum (FWHM) of the first oxide template layer 21 is ≤6°.

[0043] In one feasible embodiment, the deposition method of the first oxide template layer 21 includes ion beam assisted deposition, and the process conditions for depositing the first oxide template layer 21 satisfy at least one of the following characteristics: ion energy of 800eV–1000eV; ion incident angle of 35°–45°; ion / evaporation beam flux ratio of 0.3–0.6; and the temperature of the pretreated non-oriented silicon steel 1 is controlled at 250°C–320°C.

[0044] In one feasible embodiment, the oxide template layer 2 satisfies at least one of the following characteristics: the total thickness of the oxide template layer 2 is 70 nm–170 nm; the materials of the first oxide template layer 21 and the homogeneous oxide buffer layer 22 are magnesium oxide; the thickness of the first oxide template layer 21 is 20 nm–50 nm; and the thickness of the homogeneous oxide buffer layer 22 is 50–120 nm.

[0045] In the embodiments of this application, such as Figure 3 As shown, the oxide template layer 2 adopts a double-layer structure, including a first oxide template layer 21 and a homogeneous oxide buffer layer 22. The first oxide template layer 21 can also be called the IBAD template layer. Specifically, the materials of the first oxide template layer 21 and the homogeneous oxide buffer layer 22 are magnesium oxide, that is, the oxide template layer 2 is a magnesium oxide template layer, including a first magnesium oxide template layer and a homogeneous magnesium oxide buffer layer (homogeneous MgO buffer layer).

[0046] In step S31 above, an ion beam assisted deposition (IBAD) is used to prepare a first oxide template layer 21. Specifically, the preparation process involves an ion energy of 800–1000 eV, an incident angle of 35–45°, an ion / evaporation beam flux ratio of 0.3–0.6, and a substrate temperature controlled at 250–320°C, thereby obtaining a textured first magnesium oxide template layer. The full width at half maximum (FWHM) of the first oxide template layer 21 is ≤6°, meaning that the first oxide template layer 21 has a textured orientation structure with Δφ ≤ 6°. In other words, the IBAD template layer in this embodiment refers to a MgO thin film layer with a clear crystal texture orientation prepared using ion beam assisted deposition technology. Its main function is to construct a controllable orientation template on a non-oriented silicon steel substrate, providing an orientation basis for subsequent epitaxial growth. The substrate temperature refers to the temperature of the non-oriented silicon steel.

[0047] Optionally, this application embodiment also provides a method for testing the full width at half maximum (FWHM) Δφ of the first oxide template layer 21. Specifically, Δφ is determined by X-ray diffraction φ scanning. Specifically, the sample is scanned at a fixed diffraction angle and tilt angle, with a scanning range of 0–360°. The Δφ value is obtained by fitting the FWHM of the diffraction peak. When the FWHM of the φ scan diffraction peak is not greater than 6°, a textured orientation structure with Δφ ≤ 6° is considered to be obtained.

[0048] S33: Deposit the homogeneous oxide buffer layer 22 on the surface of the first oxide template layer 21.

[0049] In this embodiment, the oxide template layer 2 further includes a homogeneous oxide buffer layer 22, which is deposited on the surface of the first oxide template layer 21. Both the IBAD template layer and the homogeneous MgO buffer layer are made of MgO, but they differ significantly in their structural state and preparation method: the IBAD template layer forms a high-defect, strongly textured orientation-inducing layer under ion beam bombardment; the homogeneous MgO buffer layer is grown without ion assistance, focusing on reducing defect density, improving surface smoothness, and stabilizing the crystal structure. Through the division of labor and synergy between "orientation establishment" and "quality repair," they achieve a balance between high orientation and high epitaxial quality.

[0050] Optionally, the above-mentioned homogeneous oxide buffer layer 22 is prepared by conventional thermal growth direct epitaxial growth, that is, direct homogeneous epitaxy on the surface of the first magnesium oxide template layer. Conventional thermal growth direct epitaxial growth can be carried out by methods such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), radio frequency magnetron sputtering (RF Magnetron Sputtering), and atomic layer deposition (ALD).

[0051] In this embodiment, the total thickness of the oxide template layer 2 is 70 nm–170 nm; wherein, the thickness of the first oxide template layer 21 is 20 nm–50 nm; and the thickness of the homogeneous oxide buffer layer 22 is 50–120 nm. Thus, the synergistic effect of the first oxide template layer 21 and the homogeneous oxide buffer layer 22 can achieve a balance between high orientation and high epitaxial quality.

[0052] In one feasible implementation, after step S1 described above, the method further includes: S2: Deposit a diffusion barrier layer 5 on the surface of the pretreated non-oriented silicon steel 1; the material of the diffusion barrier layer 5 is either Al2O3 or Si3N4; the thickness of the diffusion barrier layer 5 is 5nm-15nm.

[0053] When the preparation method includes S2, in step S3 above, the deposition of oxide template layer 2 on the surface of the pretreated non-oriented silicon steel 1 includes: depositing the oxide template layer 2 on the surface of the diffusion barrier layer 5.

[0054] In the embodiments of this application, such as Figure 4As shown, a diffusion barrier layer 5 can also be deposited on the surface of the pretreated non-oriented silicon steel 1. The function of the diffusion barrier layer 5 is to inhibit the upward diffusion of Fe and Si elements in the non-oriented silicon steel. The material of the diffusion barrier layer 5 is either Al2O3 or Si3N4; the thickness of the diffusion barrier layer 5 is 5nm-15nm. The diffusion barrier layer 5 made of Al2O3 or Si3N4, through its high diffusion activation energy and dense structure, can effectively inhibit the migration of Fe and Si elements in the silicon steel to the upper magnesium oxide template layer and magnetic insulator layer 3 under high temperature conditions, thereby stabilizing the interface structure and improving the electromagnetic and service performance of the epitaxial film (i.e., the magnesium oxide template layer and magnetic insulator layer 3). Thus, by setting the diffusion barrier layer 5, the interface diffusion depth can be ≤5 nm.

[0055] When the preparation method includes S2, the oxide template layer 2 is located on the surface of the diffusion barrier layer 5. That is, by sequentially executing steps S1, S2 and S3, the diffusion barrier layer 5 can be set between the pretreated non-oriented silicon steel 1 and the oxide template layer 2, thereby achieving the blocking of elemental external suppression.

[0056] In one feasible implementation, in step S5 above, the deposition of a magnetic insulating layer 3 on the surface of the oxide template layer 2 to obtain a first preset silicon steel composite material includes: A magnetic insulating layer 3 is deposited on the surface of the oxide template layer 2 using pulsed laser deposition or radio frequency magnetron sputtering. The magnetic insulating layer 3 satisfies at least one of the following characteristics: the material of the magnetic insulating layer 3 is Ni. 1- x Zn x Fe2O4, wherein 0.3≤x≤0.7; the thickness of the magnetic insulator layer 3 is 100nm–500nm.

[0057] In one feasible embodiment, the process conditions for depositing the magnetic insulating layer 3 satisfy at least one of the following characteristics: deposition temperature of 500°C–650°C; energy density of 1.0 J / cm³. 2 –2.0 J / cm 2 The deposition rate was 0.05 nm / s–0.20 nm / s; the oxygen partial pressure was 0.5 Pa–3 Pa.

[0058] In this embodiment, the magnetic insulating layer 3 is made of NiZn ferrite, that is, the magnetic insulating layer 3 is a NiZn ferrite thin film, and the general chemical formula of NiZn ferrite is Ni 1-x Zn xFe2O4, where 0.3 ≤ x ≤ 0.7. NiZn ferrite was chosen as the material for the magnetic insulating layer 3 because it possesses high resistivity, low eddy current loss, and good high-frequency magnetic properties. The thickness of the magnetic insulating layer 3 is 100 nm–500 nm.

[0059] Specifically, in this application embodiment, NiZn ferrite thin films are deposited using pulsed laser deposition (PLD) or radio frequency magnetron sputtering (RF) methods at a deposition temperature of 500–650°C, an oxygen partial pressure of 0.5–3 Pa, and an energy density of 1.0–2.0 J / cm³. 2 The deposition rate is 0.05–0.20 nm / s.

[0060] Optionally, the thickness ratio of the oxide template layer 2 to the magnetic insulator layer 3 can be 1:2.

[0061] Optionally, during the fabrication of the magnetic insulator layer 3, the reflected high-energy electron diffraction signal is monitored in real time to ensure that the epitaxial layer (i.e., the magnetic insulator layer 3) is continuous, dense, and free of polycrystalline impurities. Specifically, a reflective electron diffraction (RHEED) device is configured in the deposition chamber to achieve real-time monitoring of the magnetic insulator layer 3 deposition process. Since the deposition rate of the magnetic insulator layer 3 is fixed, the fabrication time of the magnetic insulator layer 3 is also fixed. Reflection high-energy electron diffraction (RHEED) is a surface analysis technique widely used for in-situ monitoring of thin film epitaxial growth processes. It can be used to monitor the epitaxial layer growth mode, rate, and surface smoothness. The density of the magnetic insulator layer 3 can be determined by clear fringes and strong RHEED oscillations in the RHEED signal; whether impurities are generated can be determined by the presence or absence of diffraction ring replacement and whether the pattern has single-crystal symmetry.

[0062] In the embodiments of this application, the non-oriented silicon steel composite material achieves simultaneous optimization of film orientation, density, and interfacial bonding through the combined application of ion beam assisted deposition, pulsed laser deposition, or magnetron sputtering technology, which significantly improves the overall electromagnetic performance of the non-oriented silicon steel material.

[0063] In one optional embodiment, the dense layer 4 satisfies at least one of the following characteristics: the thickness of the dense layer 4 is 10 nm–50 nm; the material of the dense layer 4 is either SiNx or Al2O3.

[0064] In the embodiment of the present application, the material of the dense layer 4 is any one of SiNx or Al2O3, where 0.8 < x < 1.4, and the thickness is 10 nm - 50 nm, so as to improve the surface density of the magnetic insulator layer 3 and reduce the porosity of the magnetic insulator layer 3. Optionally, the preparation method of the densification can adopt the CVD (Chemical Vapor Deposition) method.

[0065] On the other hand, the embodiment of the present application also provides an non-oriented silicon steel composite material, and the non-oriented silicon steel composite material is prepared by the preparation method of the non-oriented silicon steel composite material described above; as Figure 2 shown, the non-oriented silicon steel composite material includes: The pretreated non-oriented silicon steel 1; The oxide template layer 2 located on the surface of the non-oriented silicon steel; The magnetic insulator layer 3 located on the surface of the oxide template layer 2; The dense layer 4 located on the magnetic insulator layer 3.

[0066] In an optional embodiment, as Figure 3 shown, the oxide template layer 2 includes a first oxide template layer 21 and a homogeneous oxide buffer layer 22. The first oxide template layer 21 is located on the surface of the pretreated non-oriented silicon steel 1, and the homogeneous oxide buffer layer 22 is located on the surface of the first oxide template layer 21; wherein, the first oxide template layer 21 is prepared by an ion beam assisted deposition process.

[0067] In an optional embodiment, as Figure 4 shown, the non-oriented silicon steel composite material further includes a diffusion barrier layer 5, and the diffusion barrier layer 5 is located between the pretreated non-oriented silicon steel 1 and the oxide template layer 2.

[0068] Optionally, the oxide template layer 2 satisfies at least one of the following characteristics: the total thickness of the oxide template layer 2 is 70 nm - 170 nm; the materials of the first oxide template layer 21 and the homogeneous oxide buffer layer 22 are magnesium oxide; the thickness of the first oxide template layer 21 is 20 nm - 50 nm; the thickness of the homogeneous oxide buffer layer 22 is 50 - 120 nm.

[0069] Optionally, the material of the diffusion barrier layer 5 is any one of Al2O3, Si3N4; the thickness of the diffusion barrier layer 5 is 5nm - 15nm.

[0070] Optionally, the magnetic insulator layer 3 satisfies at least one of the following characteristics: the material of the magnetic insulator layer 3 is Ni1-x Zn x Fe2O4, wherein 0.3≤x≤0.7; the thickness of the magnetic insulator layer 3 is 100nm–500nm.

[0071] Optionally, the initial non-oriented silicon steel has the following chemical composition by weight percentage: Si: 2.5 wt.%~4.5 wt.%, Mn: 0.1 wt.%~0.2 wt.%, C: 0.005 wt.%, Al: 0.5 wt.%~1.0 wt.%, S: 0.001 wt.%~0.002 wt.%, with the remainder being Fe and unavoidable impurities; the pretreated non-oriented silicon steel 1 is obtained by surface cleaning treatment of the initial non-oriented silicon steel.

[0072] Optionally, the dense layer 4 satisfies at least one of the following characteristics: the thickness of the dense layer 4 is 10 nm–50 nm; the material of the dense layer 4 is either SiNx or Al2O3.

[0073] The following specific embodiments illustrate the non-oriented silicon steel composite material and its preparation method provided in this application.

[0074] Example 1: This embodiment provides a method for preparing a non-oriented silicon steel composite material, the method comprising: 1. Obtain pretreated non-oriented silicon steel; 2. A diffusion barrier layer of Al2O3 with a thickness of 5 nm is deposited on the surface of the pretreated non-oriented silicon steel. 3. A first magnesium oxide template layer with a thickness of 20 nm was deposited on the surface of the diffusion barrier layer using ion beam assisted deposition. The process parameters were: ion energy 800 eV; ion incident angle 35°; ion / evaporation beam flux ratio 0.3; substrate temperature 250℃; and a homogeneous magnesium oxide buffer layer with a thickness of 50 nm was grown epitaxially. 4. A magnetic insulating layer, namely a NiZn ferrite film, is deposited on the surface of the homogeneous magnesium oxide buffer layer using pulsed laser deposition (PLD) or radio frequency magnetron sputtering (RF). The composition is Ni. 0.7 Zn 0.3 Fe2O4; thickness 100 nm; deposition temperature 500℃; oxygen partial pressure 0.5 Pa; 5. Perform post-annealing treatment. Heat treatment conditions: annealing temperature 700 ℃; holding time 10 min; 6. A sealing layer, made of SiN, is deposited on the surface of the homogeneous magnesium oxide buffer layer. x The thickness is 10 nm, and then it is baked at 100 °C for 1 hour to obtain a non-oriented silicon steel composite material.

[0075] Example 2: This embodiment provides a method for preparing a non-oriented silicon steel composite material, the method comprising: 1. Obtain pretreated non-oriented silicon steel; 2. A diffusion barrier layer of Al2O3 with a thickness of 10 nm is deposited on the surface of the pretreated non-oriented silicon steel. 3. A first magnesium oxide template layer with a thickness of 30 nm was deposited on the surface of the diffusion barrier layer using ion beam assisted deposition. The process parameters were: ion energy 900 eV; ion incident angle 40°; ion / evaporation beam flux ratio 0.45; substrate temperature 285℃; and a homogeneous magnesium oxide buffer layer with a thickness of 80 nm was grown epitaxially. 4. A magnetic insulating layer, namely a NiZn ferrite film, is deposited on the surface of the homogeneous magnesium oxide buffer layer using pulsed laser deposition (PLD) or radio frequency magnetron sputtering (RF). The composition is Ni. 0.5 Zn 0.5 Fe2O4; thickness 300 nm; deposition temperature 580℃; oxygen partial pressure 1.5 Pa; 5. Perform post-annealing treatment. Heat treatment conditions: annealing temperature 740℃; holding time 15 min. 6. A sealing pore layer of Al2O3 with a thickness of 30 nm is deposited on the surface of the homogeneous magnesium oxide buffer layer, and then baked at 100℃ for 1 hour to obtain a non-oriented silicon steel composite material.

[0076] Example 2: This embodiment provides a method for preparing a non-oriented silicon steel composite material, the method comprising: 1. Obtain pretreated non-oriented silicon steel; 2. A diffusion barrier layer of Si3N4 with a thickness of 15 nm is deposited on the surface of the pretreated non-oriented silicon steel. 3. A first magnesium oxide template layer with a thickness of 50 nm was deposited on the surface of the diffusion barrier layer using ion beam assisted deposition. The process parameters were: ion energy 1000 eV; ion incident angle 45°; ion / evaporation beam flux ratio 0.6; substrate temperature 320℃; and a homogeneous magnesium oxide buffer layer with a thickness of 120 nm was grown epitaxially. 4. A magnetic insulating layer, namely a NiZn ferrite film, is deposited on the surface of the homogeneous magnesium oxide buffer layer using pulsed laser deposition (PLD) or radio frequency magnetron sputtering (RF). The composition is Ni. 0.3 Zn 0.7 Fe2O4; thickness 500 nm; deposition temperature 650℃; oxygen partial pressure 3 Pa; 5. Perform post-annealing treatment. Heat treatment conditions: annealing temperature 780℃; holding time 20 min. 6. A sealing pore layer of Al2O3 with a thickness of 50 nm is deposited on the surface of a homogeneous magnesium oxide buffer layer, and then baked at 100°C for 1 hour to obtain a non-oriented silicon steel composite material.

[0077] Comparative Example 1: The only difference between Comparative Example 1 and Example 2 above is that the magnesium oxide template layer in step 3 was not prepared, and a NiZn ferrite film was directly deposited on the surface of the diffusion barrier layer. The other process parameters are the same as those in Example 2.

[0078] Comparative Example 2: Comparative Example 2 differs from Example 2 only in that NiZn ferrite film was not prepared; only MgO template layer, diffusion barrier layer and dense layer were prepared. All other conditions were the same as in Example 2.

[0079] Comparative Example 3: The only difference between Comparative Example 3 and Example 2 above is that a dense layer was not prepared; the other parameters are the same as those in Example 2.

[0080] Comparative Example 4: The only difference between Comparative Example 4 and Example 2 above is that no diffusion barrier layer was prepared; the other parameters are the same as those in Example 2.

[0081] The surface resistivity, iron loss reduction, coercivity and adhesion of the non-oriented silicon steel composite materials prepared in Examples 1-3 and Comparative Examples 1-4 were tested respectively. The test methods are shown in Table 1.

[0082] Table 1 The surface resistivity, iron loss reduction, coercivity, and adhesion test results of the non-oriented silicon steel composite materials prepared in Examples 1-3 and Comparative Examples 1-4 are shown in Table 2.

[0083] Table 2 A comparison of Example 2 and Comparative Example 1 shows that when no oxide template layer is provided between the non-oriented silicon steel and the magnetic insulator layer, the magnetic insulator layer is in a polycrystalline state, and the adhesion is significantly reduced, i.e., the interfacial bonding force is significantly reduced. This indicates that providing an oxide template layer between the non-oriented silicon steel and the magnetic insulator layer can significantly improve the interfacial bonding force of the magnetic insulator layer. Furthermore, the surface resistivity, iron loss reduction, and coercivity of the sample in Example 2 are all superior to those in Comparative Example 2, further demonstrating that the oxide template layer can cooperate and synergistically work with the magnetic insulator layer to achieve a low-loss, high-resistivity, and strongly adherent magnetic insulator epitaxial layer on the silicon steel material. This effectively suppresses eddy current losses, improves insulation performance, and maintains the magnetic permeability and mechanical stability of the silicon steel.

[0084] A comparison of Example 2 and Comparative Example 2 shows that when no magnetic insulating layer is prepared, the effect of reducing iron loss is limited due to the lack of magnetic insulation function.

[0085] A comparison of Example 2 and Comparative Example 3 shows that when a dense layer is not prepared, all properties decrease. This is because the porosity of the magnetic insulator layer surface increases, and the hygrothermal stability and interfacial resistance decrease.

[0086] A comparison of Example 2 and Comparative Example 4 shows that when no diffusion barrier layer is prepared, the upward diffusion of Fe and Si is significant, resulting in the appearance of impurity phases in the epitaxial layer (magnetic insulator layer), which deteriorates the insulation performance and causes a decrease in iron loss and adhesion.

[0087] This application also provides a performance comparison between the non-oriented silicon steel provided in this application and non-oriented silicon steel prepared by existing processes, as shown in Table 3.

[0088] Table 3 Specifically, the structure of the aforementioned traditional inorganic coated silicon steel consists of silicon steel and an organic coating. The organic coating has a thickness of 2μm-5μm and is prepared by electroplating or a sol-gel method. The structure of the silicon steel material corresponding to the PECVD deposited inorganic thin film, from bottom to top, includes silicon steel, a magnesium oxide layer, a NiZn ferrite layer, and a sealing layer. The magnesium oxide layer has a thickness of 70 nm-170 nm and is deposited by PECVD; the NiZn ferrite layer has a thickness of 100 nm-500 nm and is deposited by PECVD; and the sealing layer has a thickness of 10-50 nm.

[0089] The non-oriented silicon steel composite material structure prepared in the embodiments of this application is as follows: Figure 3As shown, and prepared by the method for preparing non-oriented silicon steel composite material provided in this application embodiment, the material comprises, from bottom to top, pretreated non-oriented silicon steel, a diffusion barrier layer, a magnesium oxide template layer, a magnetic insulator layer, and a dense layer. The diffusion barrier layer has a thickness of 5 nm–15 nm. The magnesium oxide template layer includes a first magnesium oxide template layer and a homogeneous magnesium oxide buffer layer. The first magnesium oxide template layer is prepared by ion beam assisted deposition (IBAD), with a Δφ≤6° and a thickness of 20–50 nm. The homogeneous magnesium oxide buffer layer has a thickness of 50–120 nm. The magnetic insulator layer is deposited by pulsed laser deposition (PLD) or radio frequency magnetron sputtering (RF), with a thickness of 100–500 nm, and is selected from Ni. 1-x Zn x Fe2O4 (0.3≤x≤0.7) system; the thickness of the dense layer is 10–50 nm.

[0090] As shown in Table 3, the preparation method of the non-oriented silicon steel composite material of this invention achieves simultaneous optimization of film orientation, density, and interfacial bonding through the combined application of ion beam-assisted deposition and pulsed laser deposition or magnetron sputtering technology, significantly improving the overall electromagnetic properties of the material. Compared with traditional electroplating, sol-gel, and PECVD processes, this method uses low heat input deposition and rapid thermal annealing, avoiding the problems of grain coarsening and magnetic property degradation in the silicon steel matrix. The prepared MgO-NiZn ferrite epitaxial film possesses high resistivity (≥1×10⁻⁶). 9 With excellent adhesion (≥25N) and Ω·m, this process effectively reduces eddy current losses by 5–12% and maintains structural stability after multiple thermal cycles. It simplifies the production process, is suitable for continuous roll-to-roll manufacturing, and possesses excellent process compatibility and industrial application value.

[0091] On the other hand, this application also provides an application of non-oriented silicon steel composite material. When non-oriented silicon steel composite material is applied to motor core laminations, it can effectively improve electromagnetic performance. Specifically, the inter-laminar resistance is increased by ≥1 order of magnitude, the total iron loss at 50–400 Hz is reduced by 5–12%, the noise level is reduced by 1–3 dB(A), and the overall performance is improved by 10–15%.

[0092] It should be noted that the embodiments of non-oriented silicon steel composite materials and the embodiments of preparation methods of non-oriented silicon steel composite materials are based on the same concept.

[0093] This application's embodiments achieve high orientation and high density of the magnetic insulating film on a non-oriented silicon steel substrate through a synergistic design of a textured magnesium oxide template layer combined with an epitaxial magnetic insulating film, thereby effectively improving insulation resistivity and eddy current resistance. Furthermore, low-heat-input deposition and rapid thermal annealing processes prevent substrate grain coarsening and magnetic property degradation, ensuring the overall mechanical stability of the material. Further, the diffusion barrier layer and surface sealing layer structure enhance the adhesion and long-term service reliability between the film layers (magnesium oxide template layer and magnetic insulating layer) and the substrate (non-oriented silicon steel), maintaining performance stability under thermal shock and long-term operating conditions. This method not only ensures comprehensive optimization of the magnetic insulating layer in terms of electromagnetic properties, heat resistance, and adhesion, but also allows for roll-to-roll continuous production, possessing high industrial application value and promising prospects for widespread adoption.

[0094] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0095] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a non-oriented silicon steel composite material, characterized in that, The preparation method includes: Obtain pretreated non-oriented silicon steel; An oxide template layer is deposited on the surface of the pretreated non-oriented silicon steel. A magnetic insulating layer is deposited on the surface of the oxide template layer to obtain a first preset silicon steel composite material; The first preset silicon steel composite material is heat-treated; A dense layer is deposited on the surface of the magnetic insulator layer to obtain a second preset silicon steel composite material. The second preset silicon steel composite material is then heat-treated to obtain a non-oriented silicon steel composite material.

2. The preparation method according to claim 1, characterized in that, The oxide template layer includes a first oxide template layer and a homogeneous oxide buffer layer; the deposition of the oxide template layer on the surface of the pretreated non-oriented silicon steel includes: The first oxide template layer is deposited on the surface of the pretreated non-oriented silicon steel; the full width at half maximum (FWHM) of the first oxide template layer is ≤6°. The homogeneous oxide buffer layer is deposited on the surface of the first oxide template layer.

3. The preparation method according to claim 2, characterized in that, The deposition method of the first oxide template layer includes ion beam assisted deposition, and the process conditions for depositing the first oxide template layer satisfy at least one of the following characteristics: The ion energy is 800 eV–1000 eV; Ion incident angle 35°–45°; Ion / evaporation beam flux ratio: 0.3–0.6; The temperature of the pretreated non-oriented silicon steel is controlled at 250℃–320℃.

4. The preparation method according to claim 2, characterized in that, The oxide template layer satisfies at least one of the following characteristics: The total thickness of the oxide template layer is 70 nm–170 nm; The materials of the first oxide template layer and the homogeneous oxide buffer layer are magnesium oxide; The thickness of the first oxide template layer is 20 nm–50 nm; The thickness of the homogeneous oxide buffer layer is 50–120 nm.

5. The preparation method according to claim 1, characterized in that, After obtaining the pretreated non-oriented silicon steel, the method further includes: A diffusion barrier layer is deposited on the surface of the pretreated non-oriented silicon steel; the material of the diffusion barrier layer is either Al2O3 or Si3N4; the thickness of the diffusion barrier layer is 5nm-15nm. The deposition of an oxide template layer on the surface of the pretreated non-oriented silicon steel includes: The oxide template layer is deposited on the surface of the diffusion barrier layer.

6. The preparation method according to claim 1, characterized in that, The deposition of a magnetic insulating layer on the surface of the oxide template layer yields a first pre-defined silicon steel composite material, comprising: A magnetic insulating layer is deposited on the surface of the oxide template layer using pulsed laser deposition or radio frequency magnetron sputtering. The magnetic insulating layer satisfies at least one of the following characteristics: The material of the magnetic insulating layer is Ni. 1-x Zn x Fe2O4, where 0.3≤x≤0.7; The thickness of the magnetic insulating layer is 100nm–500nm.

7. The preparation method according to claim 6, characterized in that, The process conditions for depositing the magnetic insulating layer satisfy at least one of the following characteristics: The deposition temperature is 500℃–650℃; The energy density is 1.0 J / cm²–2.0 J / cm²; The deposition rate was 0.05 nm / s–0.20 nm / s; The partial pressure of oxygen is 0.5 Pa–3 Pa.

8. The preparation method according to claim 1, characterized in that, The process of obtaining pretreated non-oriented silicon steel includes: Obtain initial non-oriented silicon steel; the chemical composition of the initial non-oriented silicon steel by weight percentage is: Si: 2.5 wt.%~4.5 wt.%, Mn: 0.1 wt.%~0.2 wt.%, C: 0.005 wt.%, Al: 0.5 wt.%~1.0 wt.%, S: 0.001 wt.%~0.002 wt.%, with the remainder being Fe and unavoidable impurities; The initial non-oriented silicon steel is cleaned to obtain the pretreated non-oriented silicon steel; the surface roughness of the pretreated non-oriented silicon steel is ≤10nm; the cleaning method includes ion bombardment cleaning.

9. The preparation method according to claim 1, characterized in that, The dense layer satisfies at least one of the following characteristics: The thickness of the dense layer is 10 nm–50 nm; The material of the dense layer is either SiNx or Al2O3.

10. A non-oriented silicon steel composite material, characterized in that, The non-oriented silicon steel composite material is prepared by the preparation method of the non-oriented silicon steel composite material according to any one of claims 1-8; the non-oriented silicon steel composite material comprises: Pretreated non-oriented silicon steel; An oxide template layer located on the surface of the non-oriented silicon steel; A magnetic insulating layer located on the surface of the oxide template layer; A dense layer located within the magnetic insulator layer.

11. The non-oriented silicon steel composite material according to claim 10, characterized in that, The oxide template layer includes a first oxide template layer and a homogeneous oxide buffer layer. The first oxide template layer is located on the surface of the pretreated non-oriented silicon steel, and the homogeneous oxide buffer layer is located on the surface of the first oxide template layer. The first oxide template layer is prepared by an ion beam assisted deposition process.

12. The non-oriented silicon steel composite material according to claim 10, characterized in that, The non-oriented silicon steel composite material further includes a diffusion barrier layer, which is located between the pretreated non-oriented silicon steel and the oxide template layer.

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