Porcelain composition and coil component

Abstract

To provide a ceramic composition having high initial deflective strength, high deflective strength after reheating and high insulation resistance.SOLUTION: A ceramic composition of the present invention contains Fe, Cu, Zn, Mn, Co, Ni, Y and Cr. When Fe, Cu, Zn, Mn, Co and Ni are converted into Fe2O3, CuO, ZnO, MnO, CoO and NiO, respectively, and the total amount of Fe2O3, CuO, ZnO, MnO, CoO and NiO is taken as 100 mol%, the content of Fe, calculated as Fe2O3, is 41.9 mol% or more and 49.2 mol% or less; the content of Cu, calculated as CuO, is 4.4 mol% or more and 7.5 mol% or less; the content of Zn, calculated as ZnO, is 21.9 mol% or more and 36.0 mol% or less; the content of Mn, calculated as MnO, is 0.043 mol% or more and 0.867 mol% or less; the content of Co, calculated as CoO, is 0.0004 mol% or more and 1.2293 mol% or less; and the content of Ni is the balance. The ceramic composition contains, relative to 100 pts.wt. of a total Fe2O3, CuO, ZnO, MnO, CoO and NiO, the content of Y, as calculated as Y2O3, is 5 ppm or more and 800 ppm or less; the content of Cr, calculated as Cr2O3, is 5 ppm or more and 800 ppm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a ceramic composition and a coil component.

Background Art

[0002] Patent Document 1 discloses a wound coil device using a drum core having a bobbin portion and a flange portion. According to the coil device described in Patent Document 1, the first mounting convex portion formed on the flange portion at one end of the bobbin portion and the second mounting convex portion formed on the flange portion at the other end of the bobbin portion are arranged with a displacement, so that it is said to have excellent heat shock resistance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 describes that the drum core is produced by molding and sintering a ferrite material such as Ni-Zn-based ferrite or Mn-Zn-based ferrite.

[0005] The production of the drum core of a wound coil device usually involves forming and firing a powder of a ferrite material to obtain a sintered body, and then, in a semi-finished state, further heating (reheating) steps for baking electrodes formed on the drum core legs. However, the drum core made of the ferrite material described in Patent Document 1 may have its strength reduced by impacts received during transportation or additional processes such as barrel polishing, and there is a risk that sufficient mounting strength cannot be obtained due to this influence.

[0006] The present invention has been made to solve the above problems and aims to provide a porcelain composition that has high initial flexural strength and flexural strength after reheating, as well as high insulation resistance. Furthermore, the present invention aims to provide a coil component comprising a ceramic core made of the above porcelain composition. [Means for solving the problem]

[0007] The porcelain composition of the present invention is a porcelain composition containing Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr, wherein when Fe, Cu, Zn, Mn, Co, and Ni are converted to Fe2O3, CuO, ZnO, MnO, CoO, and NiO respectively, and the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO is set to 100 mol%, the amount of Fe converted to Fe2O3 is 41.9 mol% or more and 49.2 mol% or less, and the amount of Cu converted to CuO is 4.4 mol% or more and 7.5 mol% or less. The mixture contains Zn at a concentration of 21.9 mol% or more and 36.0 mol% or less when converted to ZnO, Mn at a concentration of 0.043 mol% or more and 0.867 mol% or less when converted to MnO, Co at a concentration of 0.0004 mol% or more and 1.2293 mol% or less when converted to CoO, with Ni as the remainder. Per 100 parts by weight of the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, it contains Y at a concentration of 5 ppm or more and 800 ppm or less when converted to Y2O3, and Cr at a concentration of 5 ppm or more and 800 ppm or less when converted to Cr2O3.

[0008] The coil component of the present invention comprises a ceramic core made from the porcelain composition of the present invention. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a porcelain composition that has high initial flexural strength and flexural strength after reheating, as well as high insulation resistance. Furthermore, according to the present invention, it is possible to provide a coil component comprising a ceramic core made from the above-mentioned porcelain composition. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 is a schematic front view showing an example of a coil component of the present invention. [Figure 2] Figure 2 is a schematic perspective view showing an example of a ceramic core that constitutes the coil component shown in Figure 1. [Modes for carrying out the invention]

[0011] The following describes the porcelain composition and coil component of the present invention. However, the present invention is not limited to the following configurations and can be modified and applied as appropriate without altering the essence of the invention. Furthermore, a combination of two or more of the individual desirable configurations of the present invention described below also constitutes the present invention.

[0012] [Porcelain composition] The porcelain composition of the present invention contains Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr. The porcelain composition of the present invention mainly contains, for example, ferrite, preferably spinel-type ferrite.

[0013] In this specification, "porcelain composition" means a sintered body, and preferably a core-shaped sintered body. Therefore, the porcelain composition of the present invention is a mixture of the above atoms at the atomic level. In other words, the porcelain composition of the present invention is synonymous with a ferrite sintered body.

[0014] The porcelain composition of the present invention contains Fe, Cu, Zn, Mn, Co, and Ni converted to Fe2O3, CuO, ZnO, MnO, CoO, and NiO respectively, and when the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO is set to 100 mol%, Fe is at least 41.9 mol% and no more than 49.2 mol% when converted to Fe2O3, Cu is at least 4.4 mol% and no more than 7.5 mol% when converted to CuO, Zn is at least 21.9 mol% and no more than 36.0 mol% when converted to ZnO, Mn is at least 0.043 mol% and no more than 0.867 mol% when converted to MnO, Co is at least 0.0004 mol% and no more than 1.2293 mol% when converted to CoO, and Ni is the remainder.

[0015] The porcelain composition of the present invention further contains, per 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, Y in an amount of 5 ppm to 800 ppm when converted to Y2O3, and Cr in an amount of 5 ppm to 800 ppm when converted to Cr2O3.

[0016] The porcelain composition of the present invention can achieve high initial flexural strength and flexural strength after reheating, as well as high insulation resistance, by setting the content of Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr within the above ranges. For example, a porcelain composition can be obtained that has an initial flexural strength of 190 N or more, a flexural strength after reheating of 200 N or more, and an electrical resistance of 10 or more in logarithmic notation, as described in the examples below.

[0017] The porcelain composition of the present invention preferably contains Fe at a concentration of 44.4 mol% or more and 49.2 mol% or less when converted to Fe2O3, CuO, ZnO, MnO, CoO, and NiO, respectively, and when the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO is set to 100 mol%, Fe at a concentration of 44.4 mol% or more and 49.2 mol% or less when converted to Fe2O3, Zn at a concentration of 26.9 mol% or more and 33.0 mol% or less when converted to ZnO, and Co at a concentration of 0.0004 mol% or more and 0.2500 mol% or less when converted to CoO.

[0018] By setting the Fe, Zn, and Co content within the above preferred ranges, the porcelain composition of the present invention can achieve high initial flexural strength, flexural strength after reheating, and insulation resistance, as well as high initial permeability and Curie temperature. For example, as described in the examples below, a porcelain composition can be obtained with an initial flexural strength of 190 N or more, a flexural strength after reheating of 200 N or more, an electrical resistance of 10 or more in logarithmic form, an initial permeability μ' of 400 or more, and a Curie temperature of 150°C or higher.

[0019] In the porcelain composition of the present invention, it is preferable to contain Y in terms of Y2O3 in an amount of 5 ppm or more and 600 ppm or less with respect to a total amount of 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO. By setting the content of Y in the porcelain composition of the present invention within the above-preferred range, the flexural strength after reheating can be further increased. For example, it is possible to obtain a magnetic composition in which the flexural strength after reheating described in the examples below is 210 N or more and the strength increase rate obtained by comparing the initial flexural strength and the flexural strength after reheating is 110% or more. It is more preferable to contain Y in terms of Y2O3 in an amount of 50 ppm or more and 600 ppm or less. The content of Y in the porcelain composition of the present invention, in terms of Y2O3, may be, for example, 400 ppm or less with respect to a total amount of 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO.

[0020] In the porcelain composition of the present invention, it is preferable to contain Cr in terms of Cr2O3 in an amount of 10 ppm or more and 600 ppm or less with respect to a total amount of 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO. By setting the content of Cr in the porcelain composition of the present invention within the above-preferred range, the flexural strength after reheating can be further increased. For example, it is possible to obtain a magnetic composition in which the flexural strength after reheating described in the examples below is 210 N or more and the strength increase rate obtained by comparing the initial flexural strength and the flexural strength after reheating is 110% or more. It is more preferable to contain Cr in terms of Cr2O3 in an amount of 50 ppm or more and 600 ppm or less. The content of Cr in the porcelain composition of the present invention, in terms of Cr2O3, may be, for example, 400 ppm or less with respect to a total amount of 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO.

[0021] In the present invention, the content of each element can be determined by analyzing the composition of the porcelain composition using inductively coupled plasma optical emission / mass spectrometry (ICP-AES / MS).

[0022] The porcelain composition of the present invention may further contain other elements. Further, the porcelain composition of the present invention may further contain inevitable impurities. Examples of the inevitable impurities include typical metals such as B, C, Si, S, Cl, As, Br, I, Li, Na, Mg, Al, K, Ca, Ga, Ge, Sr, Cd, In, Sn, Sb, Ba, Pb, Bi, and transition metals such as Sc, Ti, V, Nb, Mo, Pd, Ag, Hf, etc.

[0023] The porcelain composition of the present invention is preferably manufactured as follows.

[0024] First, weigh Fe2O3, CuO, ZnO, NiO, MnO, CoO, Y2O3 and Cr2O3 so that the composition after firing becomes a predetermined composition. Put this blended raw material into a ball mill together with pure water and PSZ (partially stabilized zirconia) balls, and mix and grind wet for a predetermined time (for example, 4 hours or more and 8 hours or less). After evaporating and drying this, calcine at a predetermined temperature (for example, 700 °C or more and 800 °C or less) for a predetermined time (for example, 2 hours or more and 5 hours or less) to produce a calcined product (calcined powder).

[0025] Put the obtained calcined product (calcined powder) into a ball mill together with pure water, polyvinyl alcohol as a binder, a dispersant, a plasticizer and PSZ balls, and mix and grind wet. Dry and granulate this mixed and ground slurry with a spray dryer to produce granular powder.

[0026] Prepare a mold, and press-mold the produced granular powder to form a molded body.

[0027] Next, hold the molded body in a firing furnace at a predetermined temperature (for example, 1000 °C or more and 1200 °C or less) for a predetermined time (for example, 2 hours or more and 5 hours or less) and fire it. Through the above steps, a porcelain composition is obtained.

[0028] The formation of ferrite is represented by, for example, the following chemical formula. MO + Fe2O3 → MFe2O4 (Here, M represents a metal such as Zn, Ni, Cu, Mn, Co, etc.) By designing the porcelain composition of the present invention to intentionally leave excess MO or Fe2O3, or to utilize impurities, conditions are made to facilitate the formation of ferrite during reheating, thereby repairing scratches that could become fracture initiation points. In this invention, by optimizing both the Y2O3 acting on M in MFe2O4 and the Cr2O3 acting on Fe, an improvement in the flexural strength of the porcelain composition after reheating can be obtained.

[0029] By setting the Y2O3 content in the porcelain composition to 5 ppm to 800 ppm per 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, ZnO and CuO, which contribute to diffusion during subsequent reheating, are trapped during firing. This makes the ferrite reaction more likely to occur during reheating, thus improving the strength of the porcelain composition. If the Y2O3 content exceeds 800 ppm, a separate phase consisting of many unreacted substances is formed in the ferrite, creating a fracture initiation point, and insufficient strength (initial flexural strength and flexural strength after reheating) cannot be obtained.

[0030] By setting the Cr2O3 content in the porcelain composition to 5 ppm to 800 ppm relative to 100 parts by weight of the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, the reaction of Fe2O3 during firing is suppressed, and by retaining Fe2O3 until reheating, the ferrite reaction becomes more likely to occur during reheating, leading to improved strength. If the Cr2O3 content exceeds 800 ppm, a spinel phase derived from Cr is generated in the ferrite, becoming a fracture initiation point, and sufficient strength (initial flexural strength and flexural strength after reheating) cannot be obtained.

[0031] The porcelain composition of the present invention can be used, for example, as a ceramic core for coil components, and is particularly suitable for use as a ceramic core for wound coil components. However, the applications of the porcelain composition of the present invention are not particularly limited, and it may be used, for example, as a base material for multilayer inductors.

[0032] [Coil parts] The coil component of the present invention comprises a ceramic core made from the porcelain composition of the present invention.

[0033] Figure 1 is a schematic front view showing an example of a coil component of the present invention. Figure 2 is a schematic perspective view showing an example of a ceramic core constituting the coil component shown in Figure 1.

[0034] Figures 1 and 2 are schematic representations, and their dimensions and aspect ratios may differ from those of the actual product.

[0035] In the following explanation, terms describing relationships between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms describing the shapes of elements do not necessarily represent only strict meanings, but rather include a range of substantially equivalent terms, such as differences of a few percent.

[0036] The coil component 10 shown in Figure 1 is a wound coil component and comprises a ceramic core 20, terminal electrodes 50, and wire (coil) 55. The ceramic core 20 is made of the porcelain composition of the present invention.

[0037] As shown in Figures 1 and 2, the ceramic core 20 includes a winding core portion 30 extending in the longitudinal direction L, and a pair of flange portions 40 provided at both ends of the winding core portion 30 opposite to each other in the longitudinal direction L. The winding core portion 30 and the flange portions 40 are integrally formed.

[0038] In this specification, as shown in Figures 1 and 2, the direction in which the pair of flange portions 40 are aligned is defined as the length direction L, the vertical direction in Figures 1 and 2 which is perpendicular to the length direction L is defined as the height direction (thickness direction) T, and the direction perpendicular to both the length direction L and the height direction T is defined as the width direction W.

[0039] The core portion 30 is formed, for example, in the shape of a rectangular parallelepiped extending in the length direction L. The central axis of the core portion 30 extends parallel to the length direction L. The core portion 30 has a pair of main surfaces 31 and 32 that are opposite to each other in the height direction T, and a pair of side surfaces 33 and 34 that are opposite to each other in the width direction W.

[0040] In this specification, the term "rectangular parallelepiped" includes rectangular parallelepipeds with chamfered corners and edges, rectangular parallelepipeds with rounded corners and edges, and so on. Furthermore, some or all of the main surface and side surfaces may have irregularities or other features.

[0041] A pair of flange portions 40 are provided at both ends of the winding core portion 30 in the longitudinal direction L. Each flange portion 40 is formed in a thin rectangular parallelepiped shape in the longitudinal direction L. Each flange portion 40 is formed to protrude around the winding core portion 30 in the height direction T and the width direction W. Specifically, the planar shape of each flange portion 40, when viewed from the longitudinal direction L, is formed to protrude from the winding core portion 30 in the height direction T and the width direction W.

[0042] Each flange portion 40 has an inner end face 41 facing the core portion 30 in the length direction L, an outer end face 42 opposite to the inner end face 41 in the length direction L, a pair of opposing side faces 43 and 44 in the width direction W, and an opposing top surface 45 and bottom surface 46 in the height direction T. The inner end face 41 of one flange portion 40 is positioned opposite the inner end face 41 of the other flange portion 40.

[0043] The inner end face 41 of each flange portion 40 is formed such that, for example, its entire surface extends perpendicular to the direction in which the central axis of the winding core portion 30 extends (in this case, the length direction L). That is, the entire surface of the inner end face 41 of each flange portion 40 is formed to extend parallel to the height direction T. However, an inclined surface may be formed on the inner end face 41 of each flange portion 40.

[0044] As shown in Figure 1, the terminal electrodes 50 are provided on at least the bottom surface 46 of each flange portion 40. The terminal electrodes 50 are electrically connected to the electrodes of the circuit board, for example, when the coil component 10 is mounted on the circuit board. The terminal electrodes 50 are made of, for example, nickel (Ni)-chromium (Cr), Ni-copper (Cu) or other Ni-based alloys, silver (Ag), copper (Cu), tin (Sn), etc.

[0045] The wire 55 is wound around the core portion 30. The wire 55 has a structure in which a core wire mainly composed of a conductive material such as Cu is covered with an insulating material such as polyurethane or polyester. Both ends of the wire 55 are electrically connected to the terminal electrodes 50, respectively.

[0046] Although not shown in Figure 1, multiple terminal electrodes 50 may be provided on the bottom surface 46 of each flange portion 40. Also, multiple wires 55 may be wound around the winding core portion 30.

[0047] The coil component of the present invention is manufactured, for example, as follows.

[0048] As described in the above [Porcelain Composition] section, a molded body is formed by pressure molding of granular powder. Next, the molded body is fired in a firing furnace at a predetermined temperature (e.g., 1000°C or higher, and 1200°C or lower) for a predetermined time (e.g., 2 hours or more, and 5 hours or less). The resulting sintered body is placed in a barrel and polished with an abrasive. This barrel polishing removes burrs from the sintered body and gives the outer surface of the sintered body (especially the corners and edges) a curved rounded shape. Through the above steps, a ceramic core as shown in Figure 2 is obtained.

[0049] Next, terminal electrodes are formed on at least the bottom surface of the flange portion of the ceramic core. For example, a conductive paste containing Ag and glass frit is applied to the bottom surface of the flange portion, and a baking treatment is performed at a predetermined temperature (e.g., 850°C or higher and 950°C or lower) to form a base metal layer. Then, a plating layer is formed by sequentially forming a Ni plating film and a Sn plating film on the base metal layer by electroplating. The plating layer may also contain copper (Cu) as a component. Alternatively, a metal terminal may be attached to the bottom surface of the flange portion to be used as a terminal electrode. For example, the baking treatment to form the base metal layer corresponds to the reheating process.

[0050] Next, after winding the wire around the core of the ceramic core, the ends of the wire and the terminal electrodes are joined by a known method such as thermocompression bonding. Through these steps, coil components such as the wound coil component shown in Figure 1 can be manufactured.

[0051] The coil components of the present invention are not limited to the embodiments described above, and various applications and modifications can be made within the scope of the present invention. Other shapes may include, for example, a top plate extending in the longitudinal direction L and connecting the flange portions. The wire may be one in which a core wire mainly composed of a conductive material such as Cu is covered with an insulating material such as polyurethane or polyester. The shape of the core is not limited to a drum core, and may also be an annular core.

[0052] In the coil component of the present invention, the shape and size of the core portion of the ceramic core, the shape and size of the flange portion of the ceramic core, the wire thickness (wire diameter), the number of turns, the cross-sectional shape of the wire, and the number of wires are not particularly limited and can be appropriately changed according to the desired characteristics and mounting location. Furthermore, the position and number of terminal electrodes can also be appropriately set according to the number of wires and application.

[0053] This specification discloses the following: <1> A porcelain composition containing Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr, When Fe, Cu, Zn, Mn, Co, and Ni are converted to Fe2O3, CuO, ZnO, MnO, CoO, and NiO respectively, and the total amount of Fe2O3, CuO, ZnO, MnO, CoO, and NiO is set to 100 mol%, the composition contains 41.9 mol% or more and 49.2 mol% or less when converted to Fe2O3, 4.4 mol% or more and 7.5 mol% or less when converted to CuO, 21.9 mol% or more and 36.0 mol% or less when converted to ZnO, 0.043 mol% or more and 0.867 mol% or less when converted to MnO, 0.0004 mol% or more and 1.2293 mol% or less when converted to CoO, and Ni as the remainder. A porcelain composition containing, per 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, Y in amounts of 5 ppm to 800 ppm (converted to Y2O3) and Cr in amounts of 5 ppm to 800 ppm (converted to Cr2O3).

[0054] <2> The above contains 44.4 mol% or more and 49.2 mol% or less of Fe when converted to Fe2O3, 26.9 mol% or more and 33.0 mol% or less of Zn when converted to ZnO, and 0.0004 mol% or more and 0.2500 mol% or less of Co when converted to CoO. <1> The porcelain composition described above.

[0055] <3> For every 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, Y is contained in an amount of 5 ppm or more and 600 ppm or less, converted to Y2O3. <1> or <2> The porcelain composition described above.

[0056] <4> For every 100 parts by weight of Fe2O3, CuO, ZnO, MnO, CoO, and NiO, the Cr content is between 10 ppm and 600 ppm when converted to Cr2O3. <1> ~ <3> A porcelain composition as described in any of the following.

[0057] <5> <1> ~ <4> A coil component comprising a ceramic core made from a porcelain composition as described in any of the above.

[0058] <6> The ceramic core includes a winding core portion extending in the longitudinal direction and a pair of flange portions provided at both ends of the winding core portion opposite to each other in the longitudinal direction, each of the flange portions having an inner end face facing the winding core portion in the longitudinal direction, an outer end face opposite to the inner end face in the longitudinal direction, a pair of sides facing each other in the width direction, and a top surface and a bottom surface facing each other in the height direction. Terminal electrodes are provided on at least the bottom surface of the flange portion of the ceramic core. A wire is wound around the winding core of the ceramic core, and the end of the wire is electrically connected to the terminal electrode. <5> The coil component described above. [Examples]

[0059] The following are examples that more specifically disclose the porcelain composition of the present invention. However, the present invention is not limited to these examples.

[0060] [Example 1] Fe2O3, CuO, ZnO, NiO, MnO, CoO, Y2O3, and Cr2O3 were weighed out so that the composition after calcination would be as shown in Table 1. This blend of raw materials was placed in a ball mill with pure water and PSZ balls and mixed and ground wet for 4 hours. After evaporation drying, the calcined material was prepared by calcining at 800°C for 2 hours.

[0061] The prepared calcined material was placed in a ball mill with pure water, polyvinyl alcohol as a binder, a dispersant, a plasticizer, and PSZ balls, and mixed and ground. This mixed and ground slurry was dried in a spray dryer and granulated to produce granular powder.

[0062] The prepared granular powder is press-molded, and the dimensions after molding are, A single-plate sample with dimensions of 4.0 mm in length (L), 2.0 mm in width (W), and 1.5 mm in height (T), or • Ring-shaped sample with an outer diameter of 20 mm, an inner diameter of 12 mm, and a thickness of 1.5 mm. A molded body was created that resulted in the following.

[0063] The prepared molded bodies were fired at 1100°C for 2 hours. Through this process, single-plate samples 1-37 and ring-shaped samples 1-37 were prepared.

[0064] For each sample, the composition of the sintered body was analyzed using ICP-AES / MS to determine the content of each element. The results are shown in Table 1. Table 1 shows the content of each element converted to oxide form.

[0065] [Initial bending strength] For the single-plate samples 1 to 37, the flexural strength was measured by a three-point bending test using an Aiko Engineering MODEL-1311VCW, with a terminal with an indenter radius of 0.5 mm lowered at 5 mm / min towards the center of the sample with a support distance of 3.2 mm. Ten measurements were taken for each sample, and the average value is shown in Table 1 as the initial flexural strength.

[0066] [Flexural strength after reheating] Next, the single-plate samples 1 to 37 were reheated at 900°C for 20 minutes (heating rate 10°C / min), the firing temperature used during electrode sintering. After cooling, the flexural strength was measured in the same manner as described above. Ten measurements were taken for each sample, and the average value is shown in Table 1 as the flexural strength after reheating. Furthermore, the strength increase rate (initial bending strength / bending strength after reheating × 100) was calculated by comparing the average values ​​of the initial bending strength and the bending strength after reheating, and is shown in Table 1.

[0067] [Initial permeability μ'] For ring-shaped samples 1 to 37, the initial permeability μ' was measured for each sample using an impedance analyzer (Agilent Technologies, 16454A-s) at a measurement frequency of 100 kHz, while the samples were housed in a permeability measuring jig (Agilent Technologies, E4990A). The results are shown in Table 1.

[0068] [Curie temperature] Using an ESPEC STH-120 constant temperature chamber and a Keysight E4980 LCR meter, the temperature characteristics of the initial permeability μ' at 100 kHz for ring-shaped samples 1-37 were measured in 5°C increments between 25°C and 250°C, and the Curie temperature (°C) was determined. The results are shown in Table 1.

[0069] [Insulation resistance] The insulation resistance values ​​in the thickness direction of ring-shaped samples 1 to 37 were measured using a Keysight 4339B high-resistance meter. The results are shown in Table 1.

[0070] [Table 1]

[0071] In Table 1, the samples marked with an asterisk (*) are comparative examples that fall outside the scope of the present invention.

[0072] Table 1 shows that for samples 2-5, 8-11, 14, 15, 18, 19, 22-24, 27-30, and 33-36, which contain Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr within predetermined ranges, porcelain compositions were obtained with an initial flexural strength of 190 N or higher, a flexural strength of 200 N or higher after reheating, and an electrical resistance of 10 or higher in logarithmic notation.

[0073] Furthermore, in samples 2-4, 9, 10, 14, 15, 18, 19, 23, 24, 27-30, and 33-36, which contain Fe in amounts of 44.4 mol% or more and 49.2 mol% or less when converted to Fe2O3, Zn in amounts of 26.9 mol% or more and 33.0 mol% or less when converted to ZnO, and Co in amounts of 0.0004 mol% or more and 0.2500 mol% or less when converted to CoO, porcelain compositions were obtained with an initial flexural strength of 190 N or more, a flexural strength of 200 N or more after reheating, an electrical resistance of 10 or more in logarithmic form, an initial permeability μ' of 400 or more, and a Curie temperature of 150 °C or higher.

[0074] Furthermore, in samples 2-5, 8-11, 14, 15, 18, 19, 22-24, 28-30, and 34-36, which contain Y in amounts of 5 ppm or more and 600 ppm or less when converted to Y2O3, a flexural strength of 210 N or more after reheating was obtained, and a porcelain composition with a strength increase rate of 110% or more when comparing the initial flexural strength with the flexural strength after reheating was obtained. [Explanation of symbols]

[0075] 10 coil components 20 Ceramic core 30-wound core 31, 32 Main surface of the winding core 33, 34 Side view of the core 40 Guard section 41 Inner end face of the flange 42 Outer end face of the flange 43, 44 Side view of the flange 45 Top surface of the flange 46 Bottom surface of the flange 50 terminal electrode 55 wires L (Length direction) T (height direction) W (width direction)

Claims

1. A porcelain composition containing Fe, Cu, Zn, Mn, Co, Ni, Y, and Cr, Fe, Cu, Zn, Mn, Co, and Ni are each Fe ２ O ３ Converted to CuO, ZnO, MnO, CoO and NiO, Fe ２ O ３ When the total amount of CuO, ZnO, MnO, CoO, and NiO is set to 100 mol%, Fe is Fe ２ O ３ Converted to CuO, it contains 41.9 mol% or more and 49.2 mol% or less, Cu converted to CuO, 4.4 mol% or more and 7.5 mol% or less, Zn converted to ZnO, 21.9 mol% or more and 36.0 mol% or less, Mn converted to MnO, 0.043 mol% or more and 0.867 mol% or less, Co converted to CoO, 0.0004 mol% or more and 1.2293 mol% or less, with Ni as the remainder. Fe ２ O ３ 、 with respect to a total amount of 100 parts by weight of CuO, ZnO, MnO, CoO and NiO, Y is 5 ppm or more and 800 ppm or less in terms of Y ２ O ３ ; Cr is 5 ppm or more and 800 ppm or less in terms of Cr ２ O ３ ; A ceramic composition containing them.

2. The aforementioned Fe is Fe ２ O ３ The porcelain composition according to claim 1, containing 44.4 mol% or more and 49.2 mol% or less when converted to ZnO, 26.9 mol% or more and 33.0 mol% or less when the Zn is converted to ZnO, and 0.0004 mol% or more and 0.2500 mol% or less when the Co is converted to CoO.

3. Fe ２ O ３ For a total amount of 100 parts by weight of CuO, ZnO, MnO, CoO, and NiO, Y is added to Y ２ O ３ The porcelain composition according to claim 1, containing 5 ppm or more and 600 ppm or less when converted to an amount.

4. Fe ２ O ３ For a total amount of 100 parts by weight of CuO, ZnO, MnO, CoO, and NiO, add Cr to Cr ２ O ３ The porcelain composition according to claim 1, containing 10 ppm or more and 600 ppm or less when converted to an amount.

5. A coil component comprising a ceramic core made from a porcelain composition according to any one of claims 1 to 4.

6. The ceramic core includes a winding core portion extending in the longitudinal direction and a pair of flange portions provided at both ends of the winding core portion opposite to each other in the longitudinal direction, each of the flange portions having an inner end face facing the winding core portion in the longitudinal direction, an outer end face opposite to the inner end face in the longitudinal direction, a pair of sides facing each other in the width direction, and a top surface and a bottom surface facing each other in the height direction. Terminal electrodes are provided on at least the bottom surface of the flange portion of the ceramic core. The coil component according to claim 5, wherein a wire is wound around the winding core portion of the ceramic core, and the end of the wire is electrically connected to the terminal electrode.

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