Composite metal magnetic body, inductor, and method for manufacturing inductor

Abstract

The present invention provides a composite metal magnetic body having insulation characteristics and an L value that are suitable, an inductor, and a method for manufacturing the inductor. A composite metal magnetic body CP according to the present disclosure comprises metal magnetic particles DP containing Fe and Si, and an oxide film OL covering the metal magnetic particles DP, wherein a plurality of the metal magnetic particles DP are bonded to one another via the oxide film OL. In relation to the content of Fe and Si in the metal magnetic particles DP, the metal magnetic particles DP contain phosphorus in the range of 23-392 ppm, chromium in the range of 24-4739 ppm, and calcium in the range of 22-968 ppm.

Description

Composite metal magnetic material, inductor, and method for manufacturing inductor

[0001] The present disclosure relates to a composite metal magnetic material, an inductor, and a method for manufacturing an inductor.

[0002] In Patent Document 1, in a coil component of a type in which a spiral coil portion covered by a magnetic body portion is in direct contact with the magnetic body portion, the magnetic body portion is mainly composed of a magnetic alloy particle group and does not contain a glass component, and an oxide film of the magnetic alloy particle is present on the surface of each magnetic alloy particle. A coil component is disclosed.

[0003] Furthermore, Patent Document 1 discloses that the magnetic alloy particles are Fe—Cr—Si alloy particles and the coil portion is an Ag particle group.

[0004] Furthermore, Patent Document 1 discloses that after stacking and thermocompression bonding a plurality of magnetic body layers containing magnetic alloy particles, a heat treatment is performed, and the heat treatment includes a debinding process and an oxide film forming process. The debinding process is performed under conditions of about 300° C. and about 1 hr, and the oxide film forming process is performed under conditions of about 750° C. and about 2 hr.

[0005] Japanese Patent Application Laid-Open No. 2012-164958

[0006] As described in Patent Document 1, when a metal magnetic material containing Fe and Si is heated around 750° C., there is a risk of rusting due to oxidation by reacting with oxygen in the atmosphere. On the other hand, when the heating temperature is lowered, Ag in the coil portion does not sinter, and the necessary DC resistance (Rdc) cannot be obtained.

[0007] Therefore, the inventor considered optimizing the oxygen atmosphere during heating. However, when heat treatment (firing) is performed in a low oxygen atmosphere (for example, about 10 ppm), Fe, which is an Fe oxide film formed by a degreasing treatment (debinding process), ２ O ３ changes to FeO, and deterioration of the L value (inductance value) when used as an inductor is confirmed. At an even lower oxygen concentration (for example, 10 －３０It was confirmed that heat treatment under ppm conditions reduced the oxide film and worsened the insulating properties. Therefore, even after examining the heating temperature and heating conditions, it was difficult to improve the insulating properties and L value of the metallic magnetic material.

[0008] In view of these challenges, the primary objective of this disclosure is to provide a composite metal magnetic material, an inductor, and a method for manufacturing an inductor having suitable insulating properties and L value by optimizing the material of the metal magnetic material.

[0009] The composite metallic magnetic material according to this disclosure comprises metallic magnetic particles containing Fe and Si, and an oxide film coating the metallic magnetic particles, wherein a plurality of the metallic magnetic particles are bonded together via the oxide film, and the metallic magnetic particles contain, with respect to the Fe and Si content of the metallic magnetic particles, 23 ppm to 392 ppm of phosphorus, 24 ppm to 4739 ppm of chromium, and 22 ppm to 968 ppm of calcium.

[0010] The inductor according to this disclosure has a base body in which a metallic magnetic layer containing the above-mentioned composite metallic magnetic material and an internal conductor are laminated.

[0011] The method for manufacturing an inductor according to this disclosure is the method for manufacturing an inductor as described above, comprising: a laminate formation step of forming a laminate by stacking the metal magnetic layer and the internal conductor; and a firing step of firing the laminate in an atmosphere with an oxygen concentration of 0.2% to 20.9%.

[0012] According to the composite metal magnetic material, inductor, and method for manufacturing the inductor described herein, suitable insulation properties and L value can be obtained.

[0013] Figure 1 is a perspective view of the inductor of this disclosure. Figure 2 is an exploded perspective view of the inductor of this disclosure. Figure 3 is a cross-sectional view of the composite metal magnetic material of this disclosure. Figure 4 is a manufacturing flow chart showing the manufacturing method of the inductor of this disclosure. Figure 5 is a table showing the results of demonstration tests relating to the inductor of this disclosure.

[0014] The composite metal magnetic material and inductor, as well as the method for manufacturing the composite metal magnetic material, will be described in detail below. While the drawings will be referenced as necessary, the illustrations are provided for illustrative purposes only to aid in understanding this disclosure, and their appearance and dimensional ratios may differ from those of the actual product.

[0015] <Description of Composite Metallic Magnetic Material> The composite metallic magnetic material CP of this disclosure will now be described. In this specification, "composite metallic magnetic material" refers to a configuration in which metal magnetic powders MP, composed of metal magnetic particles DP coated with an oxide film OL, are bonded together via the oxide film OL, as shown in Figure 3. However, it is not limited to the configuration shown in Figure 3, and for example, at least a portion of the metal magnetic powders MP may be bonded together via a resin R without an oxide film. In other words, "multiple bonding" in this specification refers to a configuration in which multiple (two or more) metal magnetic powders MP are directly bonded together or partially indirectly bonded together.

[0016] The metal magnetic powder MP comprises metal magnetic particles DP and an oxide film OL. As shown in Figure 3, a resin R may be present in the gaps between the oxide films OL of the metal magnetic particles DP, which are bonded together by the oxide film OL. As will be described later, epoxy resin is used for the resin R, but one or more resins selected from the group consisting of phenolic resin, polyester resin, polyimide resin, polyolefin resin, silicone resin, acrylic resin, polyvinyl butyral resin, cellulose resin, and alkyd resin may be used. Furthermore, the oxide film OL may contain a resin component depending on the method of forming the oxide film OL.

[0017] The average particle size of the metallic magnetic particles DP is preferably 0.2 μm or more and 20 μm or less, more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1 μm or more and 6 μm or less.

[0018] The average particle size of the metallic magnetic particles DP can be measured by the procedure described below. A sample of the inductor is cut to obtain a sample cross-section. Specifically, the sample cross-section is obtained by cutting the main body 10 (see Figure 1) through the center and the winding axis of the coil, perpendicular to the mounting surface and end face of the main body. The sample cross-section may be made flat by ion milling or the like. For the obtained cross-section, three arbitrary locations in the center of the cut surface corresponding to the central part of the main body 10 are photographed using an SEM (magnification of approximately 2000 to 3000 times). Then, in each field of view, the obtained SEM images are analyzed at three arbitrary locations in the center using image analysis software (for example, image analysis software WinROOF2021 (manufactured by Mitani Corporation)) to identify the metallic magnetic particles DP and determine the equivalent circle diameter of the metallic magnetic particles. The average value of the obtained equivalent circle diameters is taken as the average particle size of the metallic magnetic particles. In this specification, the average particle size may mean the average particle size D50 (particle size equivalent to 50% of the cumulative percentage by volume).

[0019] The metallic magnetic particles DP may be an Fe-Si alloy. The metallic magnetic particles DP may be contained in the magnetic paste. The resin components contained in the magnetic paste may disappear or remain after firing.

[0020] Furthermore, the metallic magnetic particles DP of this disclosure contain phosphorus in an amount of 23 ppm to 392 ppm, chromium in an amount of 24 ppm to 4739 ppm, and calcium in an amount of 22 ppm to 968 ppm relative to the Fe and Si content. Thus, when the metallic magnetic particles DP contain phosphorus, chromium, and calcium, as will be described in detail in the examples, a particularly high phosphorus content reduces the deposition of silica on the oxide film, resulting in a composite metallic magnetic material with suitable insulating properties and L value. Additionally, chromium and calcium can appropriately interact with phosphorus to contribute to suitable insulating properties and L value.

[0021] The "method for measuring phosphorus content," "method for measuring chromium content," and "method for measuring calcium content" described herein can be measured by the procedure described below. A sample of the inductor is cut to obtain a sample cross-section. Specifically, a sample cross-section is obtained by cutting the element 10 (see Figure 1) through the center and the winding axis of the coil, perpendicular to the mounting surface and end face of the element. For the obtained cross-section, five locations where the cross-section of the metal magnetic particle DP is exposed in the central part of the cut surface (the part surrounded by the internal conductor) corresponding to the central part of the element 10 are measured by ICP (Inductively Coupled Plasma) mass spectrometry, and the average values ​​of the phosphorus content, chromium content, and calcium content are calculated. In particular, laser application ICP mass spectrometry (for example, an analytical method using Agilent 7500 series ICP-MS from Agilent Technologies) irradiates the cross-section of the soft magnetic metal particle with laser light, and uses that energy to evaporate and atomize the soft magnetic metal particle, thereby measuring the elements contained in the soft magnetic metal particle. By controlling the laser light, it is possible to measure minute areas and the very surface.

[0022] The oxide film OL covers the surface of the metal magnetic particles DP, providing insulation between them. When the surface of the metal magnetic particles DP is covered with the oxide film OL, the insulation between the metal magnetic particles DP can be increased.

[0023] The oxide film OL is a film produced by the oxidation of metallic magnetic particles DP. The total thickness of the oxide film OL is preferably 5 nm to 100 nm, more preferably 5 nm to 50 nm, and even more preferably 5 nm to 20 nm. The thickness of the oxide film OL can be measured, for example, by polishing a sample of the inductor, taking a cross-section with a scanning electron microscope (SEM) or transmission electron microscope (TEM), and measuring the thickness of the oxide film OL covering the surface of the metallic magnetic particles DP from the obtained SEM image. The thickness of the oxide film OL is measured by taking images of three arbitrary locations in the center of a cross-section cut perpendicular to the mounting surface and end face of the base body 10, passing through the center of the base body 10 and the winding axis of the coil. The thickness of the oxide film OL is measured at three arbitrary locations in the center of each field of view. The average of these (three arbitrary locations in the center of the cross-section) × (three arbitrary locations in the center of each field of view) = nine locations may be used as the thickness of the oxide film OL.

[0024] As described above, the composite metal magnetic material CP of this disclosure is a composite metal magnetic material CP in which a plurality of metal magnetic powders MP are bonded via an oxide film OL, each MP having metal magnetic particles DP containing Fe and Si, and an oxide film OL coating the metal magnetic particles DP, wherein the metal magnetic particles DP contain phosphorus in an amount of 23 ppm to 392 ppm, chromium in an amount of 24 ppm to 4739 ppm, and calcium in an amount of 22 ppm to 968 ppm, relative to the Fe and Si content of the metal magnetic particles DP. When the metal magnetic particles DP contain phosphorus, chromium, and calcium in this way, a composite metal magnetic material with suitable insulating properties and L value can be obtained, although the details will be described in detail in the examples.

[0025] <Description of the Inductor of the Disclosure> Next, the inductor of the Disclosure will be described with reference to Figures 1 and 2. The inductor of the Disclosure comprises a base body 10 having the composite metal magnetic material described above, and a coil provided within the base body 10.

[0026] The base body 10 is, for example, a rectangular prism shape or a roughly rectangular prism shape having six faces. The corners and edges of the base body 10 may be rounded. The corners are the parts where three faces of the base body 10 intersect, and the edges are the parts where two faces of the base body 10 intersect.

[0027] Figure 1 shows the length, width, and height directions of the inductor 1 and the base body 10 as the L, W, and T directions, respectively. The length L, width W, and height T are orthogonal to each other. The mounting surface of the inductor 1 is, for example, a surface parallel to the length L and width W (LW surface).

[0028] The base body 10 shown in Figure 1 has a first main surface 11 and a second main surface 12 facing the height direction T, a first end surface 13 and a second end surface 14 perpendicular to the height direction T and facing the length direction L, and a first side surface 15 and a second side surface 16 perpendicular to the width direction W, which is perpendicular to both the length direction L and the height direction T. In the example shown in Figure 1, the first main surface 11 of the base body 10 corresponds to the mounting surface (bottom surface) of the base body 10. The second main surface 12 may also be the mounting surface of the base body 10.

[0029] The base body 10 has a laminated structure in which multiple magnetic layers, each having a metallic magnetic layer ML and an internal conductor CD, are stacked in the stacking direction (for example, the height direction T). In this embodiment, the base body 10 is constructed by stacking layers G1 to G8 as shown in Figure 2. A coil is formed by stacking multiple internal conductor CDs and connecting the internal conductor CDs between the metallic magnetic layers ML. Constructing a coil by stacking internal conductor CDs contributes to miniaturization. Note that the boundaries between each layer of the laminated structure of the base body 10 have disappeared.

[0030] The main body 10 contains a coil formed by stacking multiple internal conductors CD. In the example shown in Figure 2, two coils (a first coil and a second coil) are provided within the main body 10 along the stacking direction. More specifically, the first coil is formed by the internal conductors CD of layers G4 and G5, and the second coil is formed by the internal conductors CD of layers G2 and G3. The main component of the internal conductors CD is Ag. Using Ag can improve the inductance characteristics. As an example of the material for the internal conductors CD, metal conductors such as Cu, Au, or their alloys may be used instead of Ag. Furthermore, the inductor 1 of the first embodiment is not limited to this example, and for example, the main body 10 may contain only one coil. Alternatively, multiple coils may be arranged side by side inside the main body 10 in a direction intersecting the stacking direction (direction L in Figure 1) to form a coil array.

[0031] External electrodes E are provided on the mounting surface (first main surface 11) of the base body 10. In the example shown in Figure 2, the external electrodes E include a first external electrode E1 and a second external electrode E2 connected to each end of the first coil, and a third external electrode E3 and a fourth external electrode E4 connected to each end of the second coil. Note that two external electrodes are provided for each coil.

[0032] A through-hole conductor TH may be used to connect the coil to the external electrode E. That is, the first through-hole conductor TH1 to the fourth through-hole conductor TH4 may be provided corresponding to the first external electrode E1 to the fourth external electrode E4. Furthermore, the first through-hole conductor TH1 to the fourth through-hole conductor TH4 may extend along the lamination direction.

[0033] According to the inductor of this disclosure, because it is equipped with the composite metal magnetic material CP described above, suitable insulation characteristics and L value can be obtained.

[0034] <Explanation of the manufacturing method for the inductor> Next, the manufacturing method for the inductor of the present disclosure will be described. The manufacturing method for the inductor of the present disclosure comprises a laminate formation step of forming a laminate and a firing step. In addition, as optional steps, a pressurization step and a degreasing step may be included before the firing step. The details of each step will be described below.

[0035] -Laminate Formation Process- Prepare the magnetic material (magnetic paste) that constitutes the metallic magnetic layer ML of layers G1 to G8 as explained in Figure 2, and the conductive paste that constitutes the internal conductor CD.

[0036] As an example of a method for producing a magnetic paste, a metallic magnetic powder containing Fe and Si with a D50 (cumulative 50% particle size by volume) of 2 μm to 20 μm is prepared. The metallic magnetic powder further contains phosphorus at a concentration of 23 ppm to 392 ppm, chromium at a concentration of 24 ppm to 4739 ppm, and calcium at a concentration of 22 ppm to 968 ppm relative to the Fe and Si content. A magnetic paste is produced by kneading this metallic magnetic powder with a binder such as cellulose or polyvinyl butyral (PVB) and a solvent such as a mixture of terpineol and butyl diglycol acetate (BCA).

[0037] As a conductive paste, for example, a paste containing Ag as a conductive material is prepared. However, the conductive material is not limited to Ag; a paste made from conductive materials such as Cu, Au, or their alloys may also be used.

[0038] Using the magnetic paste and conductive paste described above, layers G1 to G8 shown in Figure 2 are prepared and laminated by screen printing or the like to form a laminate.

[0039] -Pressurization process- After laminating layers G1 to G8, layers G1 to G8 are pressurized. This pressurization may be carried out at a pressure of 300 MPa or higher. Pressurizing layers G1 to G8 can improve the packing density of the metal magnetic powder MP within the laminate of layers G1 to G8.

[0040] - Degreasing Process - As a manufacturing process of a suitable inductor manufacturing method, a degreasing process may be provided. The degreasing process is a process of removing the binder contained in the magnetic paste and the conductive paste. In the degreasing process, degreasing is performed in an atmosphere with an oxygen concentration of 0.1% or more and 21% or less. The degreasing atmosphere may contain nitrogen and air in addition to oxygen. In other words, by controlling the amount of nitrogen and air, a degreasing atmosphere with an oxygen concentration of 0.1% or more and 21% may be realized.

[0041] Further, the degreasing process may be in the range of 200°C or more and 450°C or less as the degreasing temperature, and the degreasing treatment time may be 1 hour or more and 3 hours or less. More preferably, the degreasing temperature may be in the range of 400°C or more and 450°C or less, and the degreasing time may be 1 hour or more and 1.5 hours or less. By this degreasing process, the binder contained in the magnetic paste and the conductive paste is removed.

[0042] - Firing Process Firing is performed after the degreasing process. The firing process is a process of sintering the internal conductor, forming an oxide film OL around the adjacent metal magnetic powder MP, and bonding the metal magnetic powders MP together by the formed oxide film OL. In the firing process, firing is performed in an atmosphere with an oxygen concentration of 0.2% or more and 20.9% or less. The firing atmosphere may contain nitrogen, hydrogen, and air in addition to oxygen. In other words, by controlling the amount of nitrogen, hydrogen, and air, a firing atmosphere with an oxygen concentration of 0.2% or more and 20.9% or less may be realized.

[0043] Further, the firing process may be performed at a firing temperature higher than the degreasing temperature of the aforementioned degreasing process. As an example, the firing temperature may be in the range of 500°C or more and 900°C or less, and the firing time may be 1 hour or more and 6 hours or less. More preferably, the firing temperature may be in the range of 500°C or more and 600°C or less, and the degreasing time may be 4 hours or more and 6 hours or less. By this firing process, the internal conductor is sintered, and the composite metal magnetic body of the present disclosure is manufactured.

[0044] Further, in order to increase the strength of the base body, resin may be impregnated into the gaps between the oxide films of adjacent metal magnetic particles in the base body and cured. Epoxy resin is used as the resin impregnated into the base body, but one or more resins selected from the group consisting of phenolic resin, polyester resin, polyimide resin, polyolefin resin, silicone resin, acrylic resin, polyvinyl butyral resin, cellulose resin, alkyd resin, etc. may also be used. By going through the above process, the base body of the inductor of the present disclosure is formed.

[0045] Then, an external electrode electrically connected to the internal conductor is formed on the formed base body. The external electrode is formed by electrolytic plating at a position where the through-hole conductor on the mounting surface (first main surface 11) of the base body 10 is exposed. The plating material may be Cu plating. In addition, Ni—Sn, Ni—Au, Ni—Cu and / or Cu—Ni—Au, etc. may be mentioned, but it is not limited thereto. After forming the external electrode, element individual piece cutting is performed to manufacture the inductor of the present embodiment.

[0046] The demonstration test regarding the inductor of the present disclosure will be described in detail. Specifically, the inductors described in the following Examples 1 to 5 and Comparative Examples 1 to 7 were manufactured.

[0047] - Common matters of Examples 1 to 5 and Comparative Examples 1 to 7 - All of the inductors of Examples 1 to 5 and the inductors of Comparative Examples 1 to 7 were subjected to the pressurization process, degreasing process, and firing process described in the above <Explanation of the manufacturing method of the inductor>. On the other hand, the "magnetic paste" in the laminate forming process is different for the inductors of Examples 1 to 5 and the inductors of Comparative Examples 1 to 7.

[0048] - Inductor of Example 1 - The inductor made using the magnetic paste of Example 1 contained 23 ppm of phosphorus, 93 ppm of chromium, and 36 ppm of calcium with respect to the contents of Fe and Si. The contents of phosphorus, chromium, and calcium are, as described above, the results of measuring the metal magnetic particles in the base body by ICP mass spectrometry.

[0049] -Inductor of Example 2- The inductor made using the magnetic paste of Example 2 contained 65 ppm of phosphorus, 24 ppm of chromium, and 114 ppm of calcium relative to the Fe and Si content.

[0050] -Inductor of Example 3- The inductor made using the magnetic paste of Example 3 contained 138 ppm of phosphorus, 4739 ppm of chromium, and 654 ppm of calcium relative to the Fe and Si content.

[0051] -Inductor of Example 4- The inductor made using the magnetic paste of Example 4 contained 281 ppm of phosphorus, 1251 ppm of chromium, and 968 ppm of calcium relative to the Fe and Si content.

[0052] -Inductor of Example 5- The inductor made using the magnetic paste of Example 5 contained 392 ppm of phosphorus, 829 ppm of chromium, and 22 ppm of calcium relative to the Fe and Si content.

[0053] -Inductor of Comparative Example 1- The inductor made using the magnetic paste of Comparative Example 1 contained 11 ppm of phosphorus, 99 ppm of chromium, and 87 ppm of calcium relative to the Fe and Si content.

[0054] -Inductor of Comparative Example 2- The inductor made using the magnetic paste of Comparative Example 2 contained 443 ppm of phosphorus, 1859 ppm of chromium, and 119 ppm of calcium relative to the Fe and Si content.

[0055] -Inductor of Comparative Example 3- The inductor made using the magnetic paste of Comparative Example 3 contained 562 ppm of phosphorus, 3053 ppm of chromium, and 1146 ppm of calcium relative to the Fe and Si content.

[0056] -Inductor of Comparative Example 4- The inductor made using the magnetic paste of Comparative Example 4 contained 367 ppm of phosphorus, 6 ppm of chromium, and 257 ppm of calcium relative to the Fe and Si content.

[0057] -Inductor of Comparative Example 5- The inductor made using the magnetic paste of Comparative Example 5 contained 155 ppm of phosphorus, 62 ppm of chromium, and 13 ppm of calcium relative to the Fe and Si content.

[0058] -Inductor of Comparative Example 6- The inductor made using the magnetic paste of Comparative Example 6 contained 188 ppm of phosphorus, 13,376 ppm of chromium, and 66 ppm of calcium relative to the Fe and Si content.

[0059] -Inductor of Comparative Example 7- The inductor made using the magnetic paste of Comparative Example 7 contained 219 ppm of phosphorus, 2164 ppm of chromium, and 1283 ppm of calcium relative to the Fe and Si content.

[0060] The inductors of Examples 1 to 5 and Comparative Examples 1 to 7 that were manufactured underwent (1) evaluation of the L value, (2) evaluation of the dielectric strength, and (3) evaluation of logIR. The specific evaluation methods are shown below.

[0061] (1) Evaluation of L value In this specification, "L value" is synonymous with inductance value. The L value was evaluated by measuring the inductance value using an impedance analyzer (Keysight, model number: E4990A). In this evaluation, products with a measured L value of 17.5 nH or higher were judged to be good products.

[0062] (2) Withstand Voltage Evaluation The withstand voltage evaluation was performed using a digital ultra-high resistance micro-ammeter (ADCMT, model number: 5451) to measure the withstand voltage. In this evaluation, products with a measured withstand voltage of 100V or higher were judged to be good products.

[0063] (3) logIR evaluation In this specification, "logIR" is an index related to insulation characteristics. Specifically, an example of insulation resistance is 10 Ｘ When expressed as such, it refers to X calculated by taking the logarithm. Here, logIR evaluation was performed by measuring IR using a digital ultra-high resistance micro-ammeter (ADCMT, model number: 5451). In this evaluation, products with a measured logIR of 6 or higher were judged to be good products.

[0064] Figure 5 shows the evaluation results for L value, withstand voltage, and logIR. As shown in Figure 5, the inductors of Examples 1 to 5 all performed well in terms of L value, withstand voltage, and logIR. More preferably, the inductors shown in Examples 1 to 2, which contain phosphorus at 23 ppm to 65 ppm, chromium at 24 ppm to 93 ppm, and calcium at 36 ppm to 114 ppm, can achieve more favorable L value, withstand voltage, and logIR.

[0065] On the other hand, in the inductors of Comparative Examples 1 to 7, at least one of the following evaluations—L value evaluation, withstand voltage evaluation, or logIR evaluation—failed to meet the standards for good products.

[0066] Based on the above, a composite metal magnetic material CP is obtained in which a plurality of metal magnetic powders MP, each having metal magnetic particles DP containing Fe and Si as shown in this disclosure and an oxide film OL coating the metal magnetic particles DP, are bonded together via the oxide film OL, wherein the composite metal magnetic material contains, with respect to the Fe and Si content of the metal magnetic particles DP, phosphorus in an amount of 23 ppm to 392 ppm, chromium in an amount of 24 ppm to 4739 ppm, and calcium in an amount of 22 ppm to 968 ppm.

[0067] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not construed solely by the embodiments described above, but is defined based on the claims. Furthermore, the technical scope of this disclosure includes all modifications within the meaning and scope of equivalence to the claims.

[0068] The composite metal magnetic material, inductor, and method for manufacturing the inductor of the present disclosure encompass the following embodiments: <1> A composite metal magnetic material having metal magnetic particles containing Fe and Si, and an oxide film coating the metal magnetic particles, wherein a plurality of the metal magnetic particles are bonded together via the oxide film, wherein, with respect to the Fe and Si content of the metal magnetic particles, the metal magnetic particles contain phosphorus in an amount of 23 ppm to 392 ppm, chromium in an amount of 24 ppm to 4739 ppm, and calcium in an amount of 22 ppm to 968 ppm. <2> The composite metal magnetic material according to <1>, wherein, with respect to the Fe and Si content of the metal magnetic particles, the metal magnetic particles contain phosphorus in an amount of 23 ppm to 65 ppm, chromium in an amount of 24 ppm to 93 ppm, and calcium in an amount of 36 ppm to 114 ppm. <3> An inductor having a base body in which a metal magnetic layer containing the composite metal magnetic material described in <1> or <2> and an internal conductor are laminated. <4> A method for manufacturing an inductor according to <3>, comprising: a laminate formation step of forming a laminate by laminating the metal magnetic layer and the internal conductor; and a firing step of firing the laminate in an atmosphere with an oxygen concentration of 0.2% or more and 20.9%. <5> A method for manufacturing an inductor according to <4>, further comprising a degreasing step of degreasing the laminate after the laminate formation step and before the firing step. <6> A method for manufacturing an inductor according to <5>, wherein the degreasing step is performed in an atmosphere with an oxygen concentration of 0.1% or more and 21%. <7> A method for manufacturing an inductor according to <5>, wherein the degreasing temperature in the degreasing step is lower than the firing temperature in the firing step.

[0069] The composite metal magnetic materials and inductors of this disclosure, as well as the methods for manufacturing them, can be suitably used as electronic components having suitable insulating properties and L values.

[0070] 1 Inductor 10 Base body 11 First main surface 12 Second main surface 13 First end surface 14 Second end surface 15 First side surface 16 Second side surface C Coil CD Internal conductor CP Composite metal magnet DP Metal magnetic particles E External electrodes E1-E4 First external electrode to fourth external electrode G1-G8 Layer ML Metal magnetic layer MP Metal magnetic powder OL Oxide film R Resin TH Through-hole conductor TH1-TH4 First through-hole conductor to fourth through-hole conductor

Claims

1. A composite metallic magnetic material comprising metallic magnetic particles containing Fe and Si, and an oxide film coating the metallic magnetic particles, wherein a plurality of the metallic magnetic particles are bonded together via the oxide film, wherein the metallic magnetic particles contain phosphorus in an amount of 23 ppm to 392 ppm, chromium in an amount of 24 ppm to 4739 ppm, and calcium in an amount of 22 ppm to 968 ppm, relative to the Fe and Si content of the metallic magnetic particles.

2. The composite metal magnetic material according to claim 1, wherein, with respect to the Fe and Si content of the metal magnetic particles, the metal magnetic particles contain phosphorus in an amount of 23 ppm to 65 ppm, chromium in an amount of 24 ppm to 93 ppm, and calcium in an amount of 36 ppm to 114 ppm.

3. An inductor having a body in which a metallic magnetic layer containing the composite metallic magnetic material described in claim 1 or 2 and an internal conductor are laminated.

4. A method for manufacturing an inductor according to claim 3, comprising: a laminate formation step of forming a laminate by laminating the metal magnetic layer and the internal conductor; and a firing step of firing the laminate in an atmosphere with an oxygen concentration of 0.2% or more and 20.9%.

5. The method for manufacturing an inductor according to claim 4, further comprising a degreasing step of degreasing the laminate after the laminate formation step and before the firing step.

6. The method for manufacturing an inductor according to claim 5, wherein the degreasing step is performed in an atmosphere with an oxygen concentration of 0.1% or more and 21% or more.

7. The method for manufacturing an inductor according to claim 5 or 6, wherein the degreasing temperature in the degreasing step is lower than the firing temperature in the firing step.

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