Chemical mechanical polishing solution for magnetically soft alloy and polishing method

Abstract

The invention discloses a chemical mechanical polishing solution for magnetically soft alloy and a polishing method.The polishing solution is composed of, by weight, 1.3 wt%-1.8 wt% of a chelating agent, 10 wt%-13 wt% of a grinding material, 7 wt%-9 wt% of a pH buffering agent, 3 wt%-3.5 wt% of a corrosion inhibitor, 11 wt%-13 wt% of an oxidizing agent and the balance deionized water, the grinding material is acidic silica sol, the oxidizing agent is hydrogen peroxide, and the pH buffering agent is sodium hydroxide. The corrosion inhibitor is at least one of glycine, polyaspartic acid, glutamic acid and chitosan, the pH value of the polishing solution is 3-5, and the pH buffer agent is a citric acid-sodium citrate buffer solution; the polishing method comprises the following steps: grinding the magnetically soft alloy; the rough polishing slurry is used for conducting chemical mechanical polishing rough polishing on the ground magnetically soft alloy; and performing chemical mechanical polishing and fine polishing on the roughly polished magnetically soft alloy by using the polishing solution to obtain the magnetically soft alloy with a smooth and flat surface. The polishing solution is green, environment-friendly and pollution-free, and the surface of the polished magnetically soft alloy is smooth and flat.

Description

Technical Field

[0001] The invention belongs to the technical field of metal processing, and in particular relates to a chemical mechanical polishing liquid and a polishing method for soft magnetic alloys. Background Art

[0002] Soft magnetic alloys, primarily composed of elements such as iron (Fe), chromium (Cr), silicon (Si), and aluminum (Al), play an indispensable role in numerous key fields, including electronics and information technology, power transmission, aerospace, and precision instrument manufacturing, thanks to their superior properties, including high magnetic permeability, low coercivity, and low hysteresis loss. They are key materials for various precision instruments and navigation equipment, motors, sensors, and magnetic recording heads. With the continuous advancement of technology, the requirements for the surface quality and precision of soft magnetic alloys are increasing. Surface quality directly affects the magnetic properties, corrosion resistance, and service life of soft magnetic alloys.

[0003] Chemical mechanical polishing (CMP) is an ultra-precision machining process that combines chemical reaction and mechanical removal. Through the coupling between the polishing pad, polishing slurry and workpiece, the workpiece surface is continuously refined. It can effectively remove microscopic defects on the workpiece surface, reduce surface roughness and improve surface flatness, thereby meeting the strict requirements of soft magnetic alloys in high-end applications.

[0004] As a core component of chemical mechanical polishing (CMP) technology, the performance of polishing fluids directly determines the quality, efficiency, and environmental friendliness of material surface processing. The polishing fluids used in traditional CMP processes typically contain large amounts of chemical reagents, such as strong oxidants, acids, and bases. If these chemicals are discharged without proper treatment after polishing, they can cause serious pollution to the natural environment, including soil and water. Furthermore, traditional polishing fluids and methods often produce suboptimal surface roughness and flatness when polishing soft magnetic alloys. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one problem in the prior art and to provide a chemical mechanical polishing liquid and a polishing method for soft magnetic alloys.

[0006] To achieve the above objectives, the present invention proposes a chemical mechanical polishing liquid for soft magnetic alloys, the polishing liquid being composed of the following raw material components in weight percentage: 1.3wt% to 1.8wt% of a chelating agent, 10wt% to 13wt% of an abrasive, 7wt% to 9wt% of a pH buffer, 3wt% to 3.5wt% of a corrosion inhibitor, 11wt% to 13wt% of an oxidant, and the remainder being deionized water, the abrasive being acidic silica sol, the oxidant being hydrogen peroxide, the corrosion inhibitor being at least one of glycine, polyaspartic acid, glutamic acid, and chitosan, the pH of the polishing liquid being 3 to 5, and the pH buffer being a citric acid-sodium citrate buffer.

[0007] As an optional embodiment, the chelating agent is oxalic acid or humic acid.

[0008] As an optional embodiment, the content of silicon dioxide in the acidic silica sol is 30%, and the particle size of the acidic silica sol is 10 nm to 20 nm.

[0009] As an optional embodiment, the citric acid-sodium citrate buffer solution is prepared by mixing citric acid and sodium citrate in a mass ratio of (0.5-1.5):(2-4). The mass ratio of citric acid to sodium citrate in the citric acid-sodium citrate buffer solution can be (0.5:2), (0.5:4), (1:2), or (1:3), which can be configured according to the pH adjustment requirements and the contents of the other components in the polishing liquid.

[0010] As an optional embodiment, the citric acid-sodium citrate buffer solution is prepared by mixing citric acid and sodium citrate in a mass ratio of 1:3.

[0011] As an optional embodiment, when preparing the polishing liquid, the various raw material components are mixed, subjected to ultrasonic vibration treatment, and stirred to form a uniform and stable suspension.

[0012] The present invention also proposes a polishing method for polishing soft magnetic alloys, comprising the following steps:

[0013] Grinding of soft magnetic alloys to remove deep scratches on their surfaces;

[0014] The ground soft magnetic alloy is subjected to chemical mechanical polishing using a rough polishing slurry to reduce the roughness of the soft magnetic alloy surface to a submicron level. The rough polishing process is as follows: the polishing disk speed is 60 rpm to 90 rpm, the flow rate of the polishing liquid is 10 mL / min to 15 mL / min, the polishing pressure is 30 kPa to 40 kPa, and the polishing time is 40 min to 60 min. After polishing, the soft magnetic alloy surface is cleaned and blown dry.

[0015] The soft magnetic alloy after rough polishing is subjected to chemical mechanical polishing and fine polishing using the polishing liquid described in any one of claims 1 to 6 to obtain a soft magnetic alloy with a smooth and flat surface. The polishing process of the fine polishing is as follows: the polishing disk speed is 60rpm~80rpm, the flow rate of the polishing liquid is 3mL / min~5mL / min, the polishing pressure is 30kpa~40kpa, the polishing time is 40min~60min, and the surface of the soft magnetic alloy is cleaned and blown dry after polishing.

[0016] As an optional implementation, the rough polishing slurry is prepared by mixing hydrogen peroxide, acidic silica sol, cerium oxide and deionized water.

[0017] As an optional embodiment, the grinding is performed using sandpaper with a mesh size of 2000 to 4000, and the polishing pad used in the chemical mechanical polishing process is made of frosted leather. The mesh size of the sandpaper can be selected according to the grinding roughness requirement, and can be 2000 mesh, 2500 mesh, 3000 mesh, or 4000 mesh.

[0018] As an optional embodiment, the polished surface of the soft magnetic alloy is cleaned with deionized water and anhydrous ethanol in sequence and blown dry with compressed air. The Sa value of the soft magnetic alloy after fine polishing is 0.104nm to 0.123nm.

[0019] Introduction to the working mechanism of polishing liquid and soft magnetic alloy in the CMP process:

[0020] The metal elements Al, Cr and Fe in the soft magnetic alloy are oxidized by H2O2 to form an oxide layer on the metal surface. + The Fe oxides are dissolved, while the Cr and Al oxides are almost not dissolved. 2+ and Fe 3+ The oxides produced in CMP are continuously removed by mechanical action, which improves the surface defects of the alloy and eventually forms an ultra-smooth surface of the soft magnetic alloy. Among them, the nano-scale SiO2 particles in the acidic silica sol remove the surface oxide layer and metal debris through physical friction with the help of mechanical grinding, thereby providing basic smoothness, and the acidic environment of the sol (pH 3.5) can inhibit the agglomeration of particles, ensure uniform grinding, and guarantee the dispersion stability; the chelating agent participates in the reaction, on the one hand, it dissolves and binds to Fe 3+ It forms a soluble complex to accelerate the dissolution of metals. On the other hand, its weak reducing property can partially reduce Cr 6+ Cr 3+ , avoid Cr 6+ Toxic oxides hinder the reaction; corrosion inhibitors such as glycine can form an adsorption film on the metal surface, effectively preventing direct contact between the metal and the corrosive medium, slowing down the corrosion rate of the metal, and reducing equipment damage while ensuring the smooth progress of the reaction.

[0021] Introduction to the efficacy of components in polishing liquid:

[0022] The high-hardness silica particles in the acidic silica sol can provide efficient grinding capabilities, ensuring polishing efficiency and effectiveness; the nano-scale monodisperse particle size achieves uniform surface removal, avoiding local over- or under-polishing; the low friction coefficient combined with dynamic lubrication significantly reduces surface scratches and damage; the low surface activity enables it to maintain stable dispersion in acidic environments, extending the service life of the abrasive and reducing the frequency of replacement.

[0023] As an oxidant, hydrogen peroxide itself possesses strong oxidizing properties. It oxidizes the metal surface to high-valent oxides through oxidative corrosion, increasing the chemical dissolution rate. After forming a dense oxide film, hydrogen peroxide and a chelating agent synergistically strip it, achieving dynamic oxide layer regulation, balancing passivation and corrosion, and increasing the removal rate of impurities and defects on the metal surface, thereby improving the surface quality of the polished metal. Furthermore, hydrogen peroxide is low-cost and produces non-polluting byproducts, making it a green and environmentally friendly oxidant.

[0024] The chelating agent can react with some metal ions in the soft magnetic alloy to promote the dissolution of the material; the chelating agent is preferably oxalic acid or humic acid. Oxalic acid and humic acid are non-toxic and harmless organic acids, environmentally friendly, and can prevent metal ions from being released and polluting the environment.

[0025] Corrosion inhibitors can effectively inhibit excessive corrosion and protect the surface of soft magnetic alloys. Glycine, polyaspartic acid, glutamic acid, and chitosan are preferred because they are green and environmentally friendly.

[0026] The pH buffer is preferably a citric acid-sodium citrate buffer, which is green and pollution-free, and replaces traditional strong acid reagents to provide a stable acidic environment for the polishing process, which not only reduces the harm to the environment, but also can more accurately control the chemical reaction rate. It maintains the pH of the polishing liquid at 3-5 through pH control, ensuring the chelating activity of the chelating agent and inhibiting the rapid decomposition of hydrogen peroxide. It also plays an important role in pH buffering, and can effectively resist the influence of a small amount of external acid or base on the pH value of the system, ensuring the relative stability of the reaction environment, and providing suitable and stable pH conditions for the entire reaction process.

[0027] The beneficial effects of the present invention are as follows: the present invention adopts a special ratio of chelating agent, abrasive, pH buffer, corrosion inhibitor and oxidant, and the pH value of the polishing liquid is 3-5. The components work synergistically with each other, thereby improving the polishing effect of the polishing liquid on the soft magnetic alloy, removing micro defects on the surface of the soft magnetic alloy, and making the surface of the soft magnetic alloy smooth and flat with low roughness after polishing; each component in the polishing liquid is selected from green, environmentally friendly and pollution-free reagents, so that the polishing liquid will not cause pollution to the environment after polishing, and the preparation process is simple; the polishing method adopts a combination of grinding, chemical mechanical polishing, rough polishing and fine polishing to achieve atomic-level removal and flattening of the surface of the soft magnetic alloy, thereby preparing an ultra-smooth surface with almost no damage.

[0028] The features and advantages of the present invention will be described in detail through embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the surface roughness and morphology of the soft magnetic alloy obtained in Example 1 of the present application.

[0030] Figure 2This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 1 of this application.

[0031] Figure 3 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 2 of this application.

[0032] Figure 4 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 3 of this application.

[0033] Figure 5 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 4 of this application.

[0034] Figure 6 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 5 of this application.

[0035] Figure 7 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 6 of this application.

[0036] Figure 8 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 7 of this application.

[0037] Figure 9 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 8 of this application.

[0038] Figure 10 This is the surface roughness and morphology of the soft magnetic alloy obtained in Control Example 9 of this application. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0040] The present invention will be described in detail below with reference to the accompanying drawings.

[0041] Example 1

[0042] This embodiment provides a chemical mechanical polishing liquid for soft magnetic alloys, which is composed of the following raw material components in weight percentage: 1.6wt% oxalic acid, 11wt% acidic silica sol, 8wt% citric acid-sodium citrate buffer, 3.2wt% glycine, 12wt% hydrogen peroxide, and the balance deionized water. The pH of the polishing liquid is 3.5, the content of silicon dioxide in the acidic silica sol accounts for 30%, and the citric acid-sodium citrate buffer is a mixture of citric acid and sodium citrate in a mass ratio of 1:3.

[0043] This embodiment also provides a polishing method for polishing a soft magnetic alloy, comprising the following steps:

[0044] The soft magnetic alloy was ground with 3000-grit sandpaper for 2 minutes to remove deep scratches on its surface. After grinding, the surface was cleaned with deionized water and anhydrous ethanol in sequence and dried with compressed air.

[0045] The ground soft magnetic alloy is subjected to chemical mechanical polishing using a coarse polishing slurry to reduce the roughness of the soft magnetic alloy surface to a submicron level. The coarse polishing slurry is prepared by 2 wt% hydrogen peroxide, 6 wt% acidic silica sol (30%), 1.25 wt% cerium oxide, and the balance deionized water. The rough polishing process is as follows: the polishing disk speed is 80 rpm, the flow rate of the polishing liquid is 10 mL / min, the polishing pressure is 38.9 kPa, and the polishing time is 40 min. Magnetic stirring is used during the polishing process to maintain the uniformity of the coarse polishing slurry. After polishing, the soft magnetic alloy surface is cleaned with deionized water and anhydrous ethanol in sequence, and then blown dry with compressed air.

[0046] The polishing liquid of this embodiment is used to perform chemical mechanical polishing and fine polishing on the soft magnetic alloy after rough polishing to obtain a soft magnetic alloy with a smooth surface. The polishing process of fine polishing is as follows: the polishing disk speed is 60 rpm, the flow rate of the polishing liquid is 5 mL / min, the polishing pressure is 38.9 kPa, and the polishing time is 45 min. Magnetic stirring is used during the polishing process to maintain the uniformity of the polishing liquid. After polishing, the surface of the soft magnetic alloy is cleaned with deionized water and anhydrous ethanol in turn, and then blown dry with compressed air.

[0047] The surface roughness and morphology of the soft magnetic alloy after fine polishing were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 1 , the detection range is 50×50μm 2 Under the condition of the present invention, the minimum surface roughness Sa of the soft magnetic alloy after polishing by the polishing method is 0.104 nm, and the surface is smooth without obvious protrusions.

[0048] Example 2

[0049] This embodiment provides a chemical mechanical polishing liquid for soft magnetic alloys, which is composed of the following raw material components in weight percentage: 1.3wt% humic acid, 10wt% acidic silica sol, 7wt% citric acid-sodium citrate buffer, 3wt% glutamic acid, 11wt% hydrogen peroxide, and the balance deionized water. The pH of the polishing liquid is 4, the content of silicon dioxide in the acidic silica sol accounts for 25%, and the citric acid-sodium citrate buffer is a mixture of citric acid and sodium citrate in a mass ratio of 1:2.

[0050] This embodiment also provides a polishing method for polishing a soft magnetic alloy, comprising the following steps:

[0051] The soft magnetic alloy was ground using 2500-grit sandpaper for 3 minutes to remove deep scratches on its surface. After grinding, the surface was cleaned with deionized water and anhydrous ethanol in sequence and dried with compressed air.

[0052] The ground soft magnetic alloy is subjected to chemical mechanical polishing using a coarse polishing slurry to reduce the roughness of the soft magnetic alloy surface to a submicron level. The coarse polishing slurry is prepared by 4 wt% hydrogen peroxide, 8 wt% acidic silica sol (30%), 1.5 wt% cerium oxide, and the balance deionized water. The rough polishing process is as follows: the polishing disk speed is 60 rpm, the flow rate of the polishing liquid is 12 mL / min, the polishing pressure is 30 kPa, and the polishing time is 50 min. Magnetic stirring is used during the polishing process to maintain the uniformity of the coarse polishing slurry. After polishing, the soft magnetic alloy surface is cleaned with deionized water and anhydrous ethanol in sequence, and then blown dry with compressed air.

[0053] The polishing liquid of this embodiment is used to perform chemical mechanical polishing and fine polishing on the soft magnetic alloy after rough polishing to obtain a soft magnetic alloy with a smooth surface. The polishing process of fine polishing is as follows: the polishing disk speed is 70 rpm, the flow rate of the polishing liquid is 3 mL / min, the polishing pressure is 30 kPa, and the polishing time is 40 min. Magnetic stirring is used during the polishing process to maintain the uniformity of the polishing liquid. After polishing, the surface of the soft magnetic alloy is cleaned with deionized water and anhydrous ethanol in turn, and then blown dry with compressed air.

[0054] The surface roughness and morphology of the soft magnetic alloy after fine polishing were measured using a 3D optical surface profiler (NewView 9000, Zygo Corporation, USA). The minimum surface roughness Sa of the soft magnetic alloy after polishing using the polishing method of the present application was 0.108 nm, and the surface was smooth without obvious protrusions.

[0055] Example 3

[0056] This embodiment provides a chemical mechanical polishing liquid for soft magnetic alloys, which is composed of the following raw material components in weight percentage: 0.7wt% of humic acid, 1.1% of oxalic acid, 13wt% of acidic silica sol, 9wt% of citric acid-sodium citrate buffer, 1wt% of glutamic acid, 1.5% of glycine, 11wt% of hydrogen peroxide, and the balance of deionized water. The pH of the polishing liquid is 3, the content of silicon dioxide in the acidic silica sol accounts for 30%, and the citric acid-sodium citrate buffer is a mixture of citric acid and sodium citrate in a mass ratio of 1:3.

[0057] This embodiment also provides a polishing method for polishing a soft magnetic alloy, comprising the following steps:

[0058] The soft magnetic alloy was ground using 4000-grit sandpaper for 5 min to remove deep scratches on its surface. After grinding, the surface was cleaned with deionized water and anhydrous ethanol in sequence and dried with compressed air.

[0059] The ground soft magnetic alloy is subjected to chemical mechanical polishing using a coarse polishing slurry to reduce the roughness of the soft magnetic alloy surface to a submicron level. The coarse polishing slurry is prepared by 3wt% hydrogen peroxide, 10wt% acidic silica sol (30%), 1.8wt% cerium oxide, and the balance deionized water. The rough polishing process is as follows: the polishing disk speed is 70rpm, the flow rate of the polishing liquid is 15mL / min, the polishing pressure is 40kPa, and the polishing time is 60min. Magnetic stirring is used during the polishing process to maintain the uniformity of the coarse polishing slurry. After polishing, the soft magnetic alloy surface is cleaned with deionized water and anhydrous ethanol in sequence, and then blown dry with compressed air.

[0060] The polishing liquid of this embodiment is used to perform chemical mechanical polishing and fine polishing on the soft magnetic alloy after rough polishing to obtain a soft magnetic alloy with a smooth surface. The polishing process of fine polishing is as follows: the polishing disk speed is 80 rpm, the flow rate of the polishing liquid is 4.5 mL / min, the polishing pressure is 40 kPa, and the polishing time is 40 min. Magnetic stirring is used during the polishing process to maintain the uniformity of the polishing liquid. After polishing, the surface of the soft magnetic alloy is cleaned with deionized water and anhydrous ethanol in turn, and then blown dry with compressed air.

[0061] The surface roughness and morphology of the soft magnetic alloy after fine polishing were measured using a 3D optical surface profiler (NewView 9000, Zygo Corporation, USA). The minimum surface roughness Sa of the soft magnetic alloy after polishing using the polishing method of the present application was 0.106 nm, and the surface was smooth without obvious protrusions.

[0062] Comparative Example 1

[0063] This control example uses a single grinding method to process the surface of the soft magnetic alloy. The specific grinding method is as follows: use 3000 mesh sandpaper to grind the soft magnetic alloy for 2 minutes. After grinding, use deionized water and anhydrous ethanol to clean the surface in turn and blow it dry with compressed air.

[0064] The surface roughness and morphology of the soft magnetic alloy after grinding were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 2 , the detection range is 50×50μm 2 In the case of , the minimum surface roughness Sa of the soft magnetic alloy after grinding is 42.260 nm, and there are a large number of scratches and protrusions on the surface.

[0065] Comparative Example 2

[0066] This control example uses a single chemical mechanical polishing method to process the surface of the soft magnetic alloy. The specific polishing method is as follows: the soft magnetic alloy is chemically mechanically polished using polishing slurry. The polishing slurry is prepared by 2wt% hydrogen peroxide, 6wt% acidic silica sol (30%) and 1.25wt% cerium oxide with the remainder being deionized water. The polishing process is as follows: the polishing disc speed is 80rpm, the flow rate of the polishing liquid is 10mL / min, the polishing pressure is 38.9kpa, and the polishing time is 40min. Magnetic stirring is used during the polishing process to maintain the uniformity of the rough polishing slurry. After polishing, the soft magnetic alloy surface is cleaned with deionized water and anhydrous ethanol in turn, and blown dry with compressed air.

[0067] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 3 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 1.808 nm, and there are pits and scratches on the surface, as well as obvious protrusions.

[0068] Comparative Example 3

[0069] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of hydrogen peroxide is adjusted to 8wt% and the weight percentage of deionized water is increased accordingly. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0070] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 4 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.109 nm, and there are a few small pits on the surface.

[0071] Comparative Example 4

[0072] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of hydrogen peroxide in the components is adjusted to 0wt% and the weight percentage of deionized water is increased accordingly. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0073] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 5 , the detection range is 50×50μm 2In the case of , the minimum surface roughness Sa of the soft magnetic alloy is 0.224 nm, and there are small pits on the surface.

[0074] Comparative Example 5

[0075] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of hydrogen peroxide is adjusted to 4wt% and the weight percentage of deionized water is increased accordingly. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0076] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 6 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.129 nm, and there are a few small pits on the surface.

[0077] Comparative Example 6

[0078] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of hydrogen peroxide in the components is adjusted to 16wt% and the weight percentage of deionized water is correspondingly reduced. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0079] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 7 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.230nm, the surface is smooth and has no obvious protrusions.

[0080] Comparative Example 7

[0081] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of glycine is adjusted to 0wt% and the weight percentage of deionized water is increased accordingly. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0082] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). See Figure 8. The measurement range is 50×50μm. 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.164nm, and there are scratches and small pits on the surface.

[0083] Comparative Example 8

[0084] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of glycine is adjusted to 1.6wt% and the weight percentage of deionized water is increased accordingly. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0085] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 9 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.190nm, and there are a few scratches and small pits on the surface.

[0086] Comparative Example 9

[0087] The polishing liquid of this control example has the same components as those of the polishing liquid of Example 1 except that the weight percentage of glycine is adjusted to 4.8wt% and the weight percentage of deionized water is correspondingly reduced. The soft magnetic alloy surface is treated using the same polishing method as in Example 1.

[0088] The surface roughness and morphology of the polished soft magnetic alloy were measured using a 3D surface optical profiler (NewView 9000, Zygo Corporation, USA). Figure 10 , the detection range is 50×50μm 2 In this case, the minimum surface roughness Sa of the soft magnetic alloy is 0.143 nm, and there are some small pits on the surface.

[0089] According to the comparison of the minimum surface roughness and surface morphology of the soft magnetic alloy in Example 1 and each control example, it can be seen that compared with the single grinding treatment in Control Example 1, the grinding + chemical mechanical rough polishing treatment in Control Example 2, and the single chemical mechanical fine polishing treatment in Control Example 3, the grinding method of Example 1 can be used to treat the soft magnetic alloy to obtain a lower surface roughness and a smoother surface. Grinding, chemical mechanical rough polishing and chemical mechanical fine polishing are combined to remove deep scratches on the metal surface by grinding, and then chemical mechanical rough polishing is used to further reduce defects such as scratches and pits, and the initial roughness is reduced from micron level to submicron level to obtain a surface of a certain quality. Finally, chemical mechanical polishing is used to achieve atomic-level removal and flattening of the soft magnetic alloy surface through the dynamic balance between chemical corrosion and mechanical grinding, thereby preparing an ultra-smooth surface with almost no damage.

[0090] Experiments have shown that the selection of the components and their proportions in the polishing solution of this application affects the subsequent polishing of soft magnetic alloys, making it difficult to achieve both the smoothness and roughness of the soft magnetic alloy surface polishing effect achieved by the polishing solution of this application. Specific experimental results are shown in Example 1 and Comparative Examples 3-9. The optimal polishing solution formula was determined by controlling the corrosion inhibitor and oxidant content of the polishing solution through single-factor experiments.

[0091] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention falls within the protection scope of the present invention.

Claims

1. A chemical mechanical polishing solution for soft magnetic alloys, characterized in that: The polishing liquid is composed of the following raw material components in weight percentage: 1.3wt% to 1.8wt% of a chelating agent, 10wt% to 13wt% of an abrasive, 7wt% to 9wt% of a pH buffer, 3wt% to 3.5wt% of a corrosion inhibitor, 11wt% to 13wt% of an oxidant, and the balance deionized water. The abrasive is acidic silica sol, the oxidant is hydrogen peroxide, the corrosion inhibitor is at least one of glycine, polyaspartic acid, glutamic acid, and chitosan, the pH of the polishing liquid is 3 to 5, and the pH buffer is a citric acid-sodium citrate buffer.

2. The chemical mechanical polishing liquid for soft magnetic alloys according to claim 1, wherein: The chelating agent is oxalic acid or humic acid.

3. The chemical mechanical polishing liquid for soft magnetic alloys according to claim 1, wherein: The content of silicon dioxide in the acidic silica sol is 30%, and the particle size of the acidic silica sol is 10 nm to 20 nm.

4. The chemical mechanical polishing liquid for soft magnetic alloys according to claim 1, wherein: The citric acid-sodium citrate buffer solution is prepared by mixing citric acid and sodium citrate in a mass ratio of (0.5-1.5): (2-4).

5. The chemical mechanical polishing liquid for soft magnetic alloys according to claim 4, wherein: The citric acid-sodium citrate buffer solution is prepared by mixing citric acid and sodium citrate in a mass ratio of 1:

3.

6. The chemical mechanical polishing liquid for soft magnetic alloys according to claim 1, wherein: When preparing the polishing liquid, the various raw material components are mixed, subjected to ultrasonic vibration treatment, and stirred to form a uniform and stable suspension.

7. A polishing method for polishing soft magnetic alloys, characterized in that: It includes the following steps: Grinding of soft magnetic alloys to remove deep scratches on their surfaces; The ground soft magnetic alloy is subjected to chemical mechanical polishing using a rough polishing slurry to reduce the roughness of the soft magnetic alloy surface to a submicron level. The rough polishing process is as follows: the polishing disk speed is 60 rpm to 90 rpm, the flow rate of the polishing liquid is 10 mL / min to 15 mL / min, the polishing pressure is 30 kPa to 40 kPa, and the polishing time is 40 min to 60 min. After polishing, the soft magnetic alloy surface is cleaned and blown dry. The soft magnetic alloy after rough polishing is subjected to chemical mechanical polishing and fine polishing using the polishing liquid described in any one of claims 1 to 6 to obtain a soft magnetic alloy with a smooth and flat surface. The polishing process of the fine polishing is as follows: the polishing disk speed is 60rpm~80rpm, the flow rate of the polishing liquid is 3mL / min~5mL / min, the polishing pressure is 30kpa~40kpa, the polishing time is 40min~60min, and the surface of the soft magnetic alloy is cleaned and blown dry after polishing.

8. The polishing method according to claim 7, wherein: The rough polishing slurry is prepared by mixing hydrogen peroxide, acidic silica sol, cerium oxide and deionized water.

9. The polishing method according to claim 7, wherein: The grinding is performed using sandpaper with 2000-4000 meshes, and the polishing pad used in the chemical mechanical polishing process is made of frosted leather.

10. The polishing method according to claim 7, wherein: After polishing, the surface of the soft magnetic alloy is cleaned with deionized water and anhydrous ethanol in sequence and blown dry with compressed air. The Sa value of the soft magnetic alloy after fine polishing is 0.104nm-0.123nm.

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