GB2189257A - High-frequency magnetic core material made of iron-based alloy - Google Patents
High-frequency magnetic core material made of iron-based alloy Download PDFInfo
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- GB2189257A GB2189257A GB08707426A GB8707426A GB2189257A GB 2189257 A GB2189257 A GB 2189257A GB 08707426 A GB08707426 A GB 08707426A GB 8707426 A GB8707426 A GB 8707426A GB 2189257 A GB2189257 A GB 2189257A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/147—Alloys characterised by their composition
- H01F1/14766—Fe-Si based alloys
- H01F1/14791—Fe-Si-Al based alloys, e.g. Sendust
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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Abstract
A high-frequency magnetic core material formed of an iron-based alloy having superior high-frequency AC magnetic characteristics is disclosed. This iron-based alloy has: a composition which contains 1-5% Si and 1-4% C, and optionally at least one element selected from the group consisting of 0.001-1% Mn, 0-0.6% P, 0-1% of at least one of Ti, Nb, Cr, Co, Ni, Cu, Mo, W, Re, Ta and Hf, 0-0.2% of at least one of Mg, Ce and Ca, and 0-0.1% of at least one of Al, As, Sb, Bi, Se, Te, Sn and S, and the balance being Fe and incidental impurities (all percentages are on a weight basis); and a structure in which 3-20% by volume of graphite is dispersed in a ferrite matrix.
Description
(b) C
Most of the carbon present in a ferrite matrix is dispersed as graphite and serves to provide the matrix with even better high-frequency AC magnetic characteristics. If the carbon content is less than 1%, the proportion of the matrix taken by graphite becomes less than 3% by volume and the intended improvement in the high-frequency AC magnetic characteristics of the matrix cannot be attained. If the carbon content exceeds 4%, the proportion of the matrix taken by graphite exceeds 20% by volume and the high-frequency
AC magnetic characteristics of the matrix are deteriorated. Therefore, the carbon content is limited to lie within the range of 14%, preferably 13%.
(c) Mn
Manganese is a deoxidizing element which, when present in the matrix, serves to improve its high-frequency magnetic properties. Manganese is therefore used if it is necessary to deoxidize the matrix during the melting or casting operation. If the Mn content is less than 0.01%, the intended deoxidation effect is not achieved. If the Mn content exceeds 1%, the high-frequency magnetic properties of the matrix are prone to be deteriorated. Therefore, the Mn content is limited to lie within the range of 0.011%, preferably 0.051%.
(d)P Phosphorus is an optional element. If it is incorporated in a ferrite matrix together with silicon, the two elements form a solid solution compound with the matrix to further increase its electrical resistance so as to provide better high-frequency AC magnetic properties. In addition, phosphorus is effective in forming a highly flowable melt for casting. If the P content is less than 0.01%, the intended effects of Pare not attained. If the P content exceeds 0.6%, the resulting magnetic core material becomes brittle. Therefore, the
P content preferably ranges from 0.01 to 0.6%.
(e) First Group of Magnetic Property Improving Components
The components of this group are optional elements. Each of the components in this group is mainly dissolved in a ferrite matrix to increase its electrical resistance, and partly dissolved in graphite to provide a uniform dispersion of graphite. As a result, the first group of magnetic property iinproving components are effective in providing the ferrite matrix with improved high-frequency AC magnetic properties. If the content of any one of these components is less than 0.05%, their intended effects are not attainable. If the content of any one of these components exceeds 1%, graphitization of the matrix is suppressed and its high-frequency AC magnetic properties are deteriorated.Therefore, the first group of magnetic property improving components are preferably incorporated in amounts ranging from 0.05 to 1%, respectively.
(f) Second Group of Magnetic Property Improving Components
The components of this group dissolve in a ferrite matrix to increase its electrical resistance and thereby improve its high-frequency AC magnetic properties. In addition, these components have a degassing activity and are capable of reducing the oxygen and nitrogen levels in the resulting alloy so as to provide better high-frequency AC magnetic properties. Therefore, the second group of magnetic improving components are used in the case where very good high-frequency AC magnetic properties are required. If the content of any one of these components is less than 0.01%, their intended effects are not attainable.If the content of any one of these components exceeds 0.2%, not only does it become difficult to achieve graphitization of the matrix but also cementite (Fe3C) begins to crystallize to deteriorate the high-frequency
AC magnetic properties of the matrix. Therefore, the second group of magnetic property improving components are preferably incorporated in amounts ranging from 0.01 to 0.2%, respectively.
(g) Third Group of Magnetic Property Improving Components
The components of this group are also optional elements. Each of the components in this group is mainly dissolved in the ferrite matrix to increase its electrical resistance and thereby provide better high-frequency AC magnetic properties. These components are also effective in producing a highly flowable melt for casting and in improving the machinability of the final product. If the content of any one of these components is less than 0.005%, their intended effects are not attainable. If the content of any one of these components exceeds 0.1%, the resulting magnetic core material has a tendency to become brittle.
Therefore, these components are preferably incorporated in amounts ranging from 0.005 to 0.1%, respectively.
(h) Volume Ratio of Graphite
As already mentioned, the high-frequency AC magnetic characteristics of a ferrite matrix are remarkably improved by incorporating a graphite dispersion. If the graphite content is less than 3% by volume, the above-described intended effect of graphite is not attainable. If the graphite content exceeds 20% by volume, the high-frequency AC magnetic properties of the matrix are susceptible to deterioration.
Therefore, the volume ratio of graphite incorporated in the present invention is within the range of from 3 to 20%, preferably from 5 to 20%.
Graphite has the ability to provide improved high-frequency AC magnetic characteristic irrespective of
SPECIFICATION
High-Frequency Magnetic Core Material Made of Iron-Based Alloy
The present invention relates to a high-frequency magnetic core material made of an iron-based alloy having superior high-frequency AC magnetic properties. This material is suitable for use as a head core or plunger yoke in a dot printer, or as a stator or rotor in a stepping motor.
The high-frequency magnetic core materials of the type contemplated by the present invention are generally required to have a short rise time for the magnetic flux to be induced by application of an electric current. To this end, the eddy-current loss produced in the magnetic core material must be decreased by increasing its electrical resistance (the eddy-current loss P accompanied by heat generation in the material is in proportion to the square of the frequency and inversely proportional to the resistance, as expressed by the following equation: B2.fe P=K
p where K: shape factor, B: flux density; f: frequency; p: electrical resistance).Therefore, in almost all cases, high-frequency magnetic core materials have been manufactured from cast Fe-base alloys that have comparatively high electrical resistivities and good magnetic properties and which contain 2-3.5 wt% of Si (all percentages given hereinafter are on a weight basis), with the balance being Fe and incidental impurities.
In modern dot-printer applications such as word processors, the production of clearer characters at a faster speed is one of the increasing needs of users. To meet this demand, it is necessary for the head core used in the dot printer to have greatly superior high-frequency magnetic properties as manifested by a reduced amount of heat generation due to eddy-currents. However, this requirement cannot be fully satisfied by any of the prior art core materials which are made of the cast Fe-base alloy described in the preceding paragraph.
An object, therefore, of the present invention is to provide a high-frequency magnetic core material that has by far superior high-frequency magnetic characteristics compared with the prior art materials. This object of the present invention can be attained by a high-frequency magnetic core material formed of an iron-based alloy that has: a composition which contains 15% Si and 14% C, and optionally at least one element selected from the group consisting of 0.011% Mn, 00.6% P, 01% of at least one of Ti, Nb, Cr,
Co, Ni, Cu, Mo, W, Re, Ta and Hf, 0-0.2% of at least one of Mg, Ce and Ca, and 00.1% of at least one of Al,
As, Sb, Bi, Se, Te, Sn and S, and the balance being Fe and incidental impurities; and a structure in which S20% by volume of graphite is dispersed in a ferrite matrix.
The present inventors conducted various studies in order to develop a high-frequency magnetic core material that would exhibit by far superior high-frequency AC magnetic properties compared with the prior art products formed of cast Fe-base alloys. The high-frequency magnetic core material of the present invention is formed of an iron-based alloy and has: a composition which contains 1-5% Si, 1-4% C, and optionally at least one element selected from the group consisting of 0.011% Mn, 0-0.6% P, 01% of at least one of Ti, Nb, Cr, Co, Ni, Cu, Mo, W, Re, Ta and Hf (these elements may collectively be referred to as the first group of components for improving the high-frequency AC magnetic properties or simply as the first group of magnetic property improving components), 00.2% of at least one of Mg, Ce and Ca (these elements may collectively be referred as the second group of components for improving the high-frequency
AC magnetic properties or simply as the second group of magnetic property improving components), and 00.1% of at least one of Al, As, Sb, Bi, Se, Te, Sn and S (these components may collectively be referred to as the third group of components for improving the high-frequency AC magnetic properties or simply as the third group of magnetic property improving components), the balance being Fe and incidental impurities; and a structure in which 320% by volume of graphite is dispersed in a ferrite matrix.
The magnetic core material of the present invention has by far superior high-frequency AC magnetic properties when compared with the prior art products formed of cast Fe-base alloys. It experiences a very low eddy-current loss and has a very short rise time during which the magnetic flux is produced upon application of an electric current. Therefore, the magnetic core material of the present invention is well capable of meeting the demand for faster and more efficient operation of modern electronic apparatus.
The present invention has been accomplished on the basis of these findings. The criticality of the compositional ranges of the components in the Fe-base alloy of which the high-frequency magnetic core material of the present invention is made is described below, as well as the criticality of the proportion of the alloy taken by graphite.
(a) Si
Silicon forms a solid solution compound with the matrix in which it is incorporated and increases its electrical resistance to provide better high-frequency AC magnetic characteristics. If the Si content is less than 1%, the intended activity of silicon is not exhibited. If the Si content exceeds 5%, the matrix is prone to become too brittle to be machined. Therefore, the Si content is limited to lie between 1 and 5%.
the shape of its particles. However, spheroidal graphite is more effective than flaky graphite when an equivalent amount in volume terms is incorporated. If spheroidal graphite is used, it desirably has an average particle size of 10-100 lim.
The following examples are provided for the purpose of further illustrating the high-frequency magnetic core material of the present invention but are in no sense to be taken as limiting.
EXAMPLE 1
Melts having the compositions shown in Table 1 were prepared in a conventional high-frequency induction melting furnace and cast into head cores (with 9 pins) for use in dot printers, with some or all of
Mg, Ce and Si (Si in the form of Fe-Se alloy) being used as alloying inoculants. When spheroidal graphite was to be formed, either Mg or Ce or both and the Fe-Si alloy were added, and when flaky graphite was to be formed, the Fe-Si alloy alone was added. The spheroidal graphite castings were annealed in a vacuum heat-treating furnace by first being held at 800 C for 30 hours, and then furnace-cooled. The flaky graphite castings were annealed in the same furnace but under different conditions, first being held at 8500C for 2 hours, and then furnace-cooled.The annealed castings had graphite particles dispersed in the ferrite matrix and were subsequently machined to attain the desired final shape. The so fabricated dot core samples Nos.
1 to 17 of the present invention were made of Fe-base alloys having the compositions and graphite volumes shown in Table 1.
Comparative sample cores Nos. 1 to 3 were fabricated by repeating the above procedures except that the melts having the compositions shown in Table 1 were immediately cast and machined to the desired final shape.
Two specimens of each dot core sample were placed side by side in such a manner that the pins on one specimen were in end-to-end registry with those on the other specimen placed in contact with the first specimen, with a non-magnetic material 0.3 mm thick being inserted between them. Coils were wound around the pins on one specimen and a rectangular pulsive voltage was applied between the coil terminals under the following conditions:
Frequency: 50 Hz
Terminal voltage: 30 volts
Current applied for: 220 ps Magnetomotive force: 150 ampere-turns (coil
current times coil turns).
the high-frequency AC magnetic characteristics of each sample were evaluated by measuring the magnetic flux, (p, flowing through the pins on the core.
Each of the pins on the dot core had a rectangular cross section with the following dimensions: 9.6 mm (length)x0.17 cm2 (effective cross-sectional area)x2.3 mm (width). Measurement of magnetic flux, (p, was conducted with a search coil and the data obtained with a waveform analyzer were processed by the following formula: = redt(Wb) Ns where Ns: search coil turns (Ns=3); e: voltage induced across the search coil.
The results are shown in Table 1 which also lists the volume ratios of graphite in the matricesofthe core samples.
TABLE 1
Fe-base Alloy Composition (wt%) Graphite Fe+ Volume Magnetic Sample lmpu- Ratio Flux qx No. Si C Mn Mg Ce rities Shape (%) (10-6 Wb) 1 1.3 1.8 - - tr bal. sphe- 5.4 10.4 roidal 2 2.8 1.9 tr " " 8.5 10.8 3 3.9 1.6 - tr tr " " 8.7 11.3 4 4.7 1.8 - tr " " ,, 10.7 11.5 5 3.1 2.0 " - - ,, flaky 9.2 10.2 6 6 1.2 1.2 - - tr " sphe- 3.2 10.1 roidal o .
C 7 3.0 2.9 flaky flaky 1 10.6 0, --- flaly 12.1 10.6 C 'a, 8 4.6 3.8 - tr tr ,, sphe- 18.8 10.3 9 9 3.2 1.7 0.056 flaky 9.4 11.6 0 10 3.0 1.9 0.54 tr - ,, sphe- 9.5 12.3 0 11 2.8 2.1 0.95 tr " " ,, 9.8 11.2 12 3.3 1.6 - 0.02 - " ! ,, 9.0 11.5 13 3.0 1.9 - - 0.06 ,, " 9.2 12.6 14 3.1 1.8 - 0.08 0.05 " " 9.6 12.9 15 2.9 1.8 - 0.18 - " ,. 9.0 11.3 16 3.1 2.2 0.48 0.09 " S, " 11.0 13.8 17 2.8 1.8 0.62 0.04 0.03 ,, ,, 8.7 13.5 1 2.4 - ~ ~ ~ " ~ ~ 8.1 Co 'S - - 9.2 The data in Table 1 shows that the dot core samples Nos. 1 to 17 of the present invention wherein spheroidel or flaky graphite particles were dispersed in a ferrite matrix had much better high-frequency AC magnetic properties than the conventional samples Nos. 1 to 3 which were solely composed of a ferrite matrix.
EXAMPLE 2
According to the procedures employed in Example 1, dot core samples Nos. 18 to 40 of the present invention were prepared. These samples were formed of Fe-base alloys having the compositions and graphite volume shown in Table 2.
the melts having the compositions shown in Table 2 were immediately cast and machined to the desired final shape.
Two specimens of each dot core sample were placed side by side in such a manner that the pins on one specimen were in end-to-end registry with those on the other specimen, which was placed in contact with the first specimen with a nonmagnetic material 0.3 mm thick inserted between them. Coils were wound around the pins on one specimen and a rectangular pulsive voltage was applied between the coil terminals under the following conditions:
Frequency: 50 Hz
Terminal voltage: 20 volts
Current applied for: 380 us Magnetomotive force: 143 ampere-turns (coil
current times coil turns).
The high-frequency AC magnetic characteristics of each sample were evaluated by measuring the magnetic flux, q), flowing through the pins on the core.
Each of the pins on the dot core had a rectangular cross section with the following dimensions: 9.6 mm (length)x0.l7 cm2 (effective cross-sectional area)x2.3 mm (width). Measurement of magnetic flux, q > , was conducted with a search coil and the data obtained with a waveform analyzer were processed by the formula shown Example 1. The results are shown in Table 2 which also lists the volume ratios of graphite in the matrices of the core samples.
The data in Table 2 shows that the dot core samples Nos. 18 to 40 of the present invention wherein graphite particles were dispersed in a ferrite matrix had much better high-frequency AC magnetic properties than the conventional samples Nos. 4 to 6 which were solely composed of a ferrite matrix. TABLE 2
Fe-Base Alloy Composition (wt%) Graphite Fe+ Volume Magnetic Sample impu- Ratio Flux # No. Si C P Mn Mg Ce Ca rities Shape (%) (10-6 Wb) 18 1.2 1.7 0.31 - - tr - bal. spheroidal 5.2 13.0 19 2.9 1.8 0.26 - tr - - " " 8.8 13.3 20 3.8 1.6 0.34 - tr tr - " " 9.0 13.7 21 4.8 1.7 0.30 - tr - - " " 10.2 13.9 22 3.0 1.8 0.24 - - - - " flaky 8.9 12.8 23 1.2 1.1 0.28 - - - tr " spheroidal 3.3 12.5 24 3.1 2.8 0.22 - - - - " flaky 12.0 13.0 25 4.7 3.7 0.17 - tr - tr " spheroidal 18.9 12.7 26 3.1 1.6 0.02 - - - - " flaky 8.2 12.7 27 2.8 1.8 0.41 - - tr - " spheroidal 8.3 13.4 28 2.7 1.5 0.56 - - - tr " " 8.0 13.0 29 3.2 1.5 0.22 0.055 - - - " flaky 9.3 13.8 30 3.0 1.8 0.32 0.52 tr - - " spheroidal 9.6 14.3 TABLE 2 (Cont'd)
Fe-Base Alloy Composition (wt%) Graphite Fe+ Volume Magnetic Sample impu- ratio flux # No. Si C P Mn Mg Ce Ca rities Shape (%) (10-6 Wb) 31 2.8 2.0 0.24 0.96 tr - - bal. spheroidal 9.8 13.7 32 3.0 1.8 0.16 - 0.03 - - " " 8.6 13.2 33 3.2 2.2 0.20 - - 0.08 - " " 10.1 13.7 34 3.1 2.0 0.18 - - - 0.02 " " 9.6 13.0 35 3.2 1.8 0.15 - 0.08 0.03 - " " 9.0 13.9 36 2.9 1.7 0.18 - 0.10 - 0.02 " " 8.5 13.8 37 3.0 1.9 0.14 - 0.18 - - " flaky 9.2 13.1 38 2.8 2.2 0.12 0.45 0.07 - - " spheroidal 10.4 14.3 39 3.1 2.1 0.14 0.58 0.04 - 0.02 " " 9.9 14.6 40 3.2 2.3 0.18 0.54 0.05 0.03 0.02 " " 10.5 15.1 4 2.6 - - - - - - " - - 10.4 5 3.0 - - - - - - " - - 11.2 6 3.6 - - - - - - " - - 11.5 (tr:Present but undetectable) EXAMPLE 3
According to the procedures employed in Example 1, dot core samples Nos. 41 to 65 of the present invention were prepared. These samples were formed of Fe-base alloys having the compositions and graphite volumes shown in Table 3.
Comparative sample cores Nos. 7 to 9 were fabricated by repeating the same procedure except that the melts having the compositions shown in Table 3 were immediately cast and machined to the desired final shape.
Two specimens of each dot core sample were placed side by side in such a manner that the pins on one specimen were in end-to-end registry with those on the other specimen, which was placed in contact with the first specimen with a nonmagnetic material 0.3 mm thick inserted between them. Coils were wound around the pins on one specimen and a rectangular pulsive voltage was applied between the coil terminals under the following conditions:
Frequency: 50 Hz
Terminal voltage: 40 volts
Current applied for: 140 pus Magnetomotive force: 143 ampere-turns (coil
current times coil turns).
The high-frequency AC magnetic characteristics of each sample were evaluated by measuring the magnetic flux, Q, flowing through the pins on the core.
Each of the pins on the dot core had a rectangular cross section with the following dimensions: 9.6 mm (length)X0.17 cm2 (effective cross-sectional area)x2.3 mm (width). Measurement of magnetic flux , was conducted with a search coil and the data obtained with a waveform analyzer were processed by the formula shown Example 1. The results are shown in Table 3 which also lists the volume ratios of graphite in the matrices of the core samples.
The data in Table 3 shows that the dot core samples Nos. 41 to 65 of the present invention wherein graphite particles were dispersed in a ferrite matrix had much better high-frequency AC magnetic properties than the conventional samples Nos. 7 to 9 which were solely composed of a ferrite matrix. TABLE 3
Fe-Base Alloy Composition (wt%) Graphite First Group of Second Group of Magnetic Prop- Magnetic Prop- Third Group of Fe+ Volume Magnetic Sample erty lmproving erty lmproving Magnetic Property lmpu- Ratio Flux # No. Si C Mn Components Components lmproving Components rities Shapa (%) (10-6 Wb) 41 3.0 2.1 0.60 Ti:0.06 -* - bal. sphe- 9.5 14.2 riodal 42 3.3 2.4 0.55 Cu:0.25 -* - " " 11.1 14.6 43 3.1 2.2 0.61 Co:0.95 -* - " " 9.8 13.3 44 1.2 2.0 0.56 Mo:0.24 -* - " " 7.6 12.7 45 4.8 1.8 0.55 W:0.29 -* - " " 10.4 14.8 46 2.4 1.1 0.41 Ta: :0.14 - - " flaky 3.4 12.0 47 3.6 3.9 0.47 Nb:0.11, W:0.25 -* - " sphe- 19.0 13.6 roidal 48 3.2 2.1 0.02 Ti:0.08, Cr:0.10, -* - " " 10.2 13.7 Ni:0.12, W:0.17 49 2.8 1.9 0.47 Re:0.23 Ca:0.02 - " " 8.9 14.8 50 2.7 1.8 0.42 Nb:0.11, Hf:0.20 Mg:0.11 - " " 9.2 15.5 51 3.0 2.0 0.64 Cr:0.39 Ce::0.18 - " " 9.5 14.1 TABLE 3 (Cont'd)
Fe-Base Alloy Composition (wt%) Graphite First Group of Second Group of Magnetic Prop- Magnetic Prop- Third Group of Fe+ Volume Magnetic Sample erty lmproving erty lmproving Magnetic Property lmpu- Ratio Flux # No. Si C Mn Components Components lmproving Components rities Shapa (%) (10-6 Wb) 52 3.1 2.5 0.98 Ni:0.65 Mg:0.08,Ca:0.04 - bal. sphe- 11.1 13.7 roidal 53 3.5 1.8 0.42 Ti:0.16,Re:0.13 -* Al:0.006 " " 9.5 14.7 54 2.7 2.0 0.48 Nb;0.19, Cu:0.06, -* As:0.021 " flaky 8.9 12.9 Hf:0.11 55 2.8 1.8 0.59 Nb:0.19 - Sb:0.044 " sphe- 8.6 14.8 roidal 56 2.7 3.1 0.54 Re:0.16 -* Bi:0.097 " " 9.5 12.9 57 3.4 2.7 0.57 Hf:0.24 -* Se:0.021 " " 12.1 14.7 58 3.1 2.5 0.49 Cr:0.25, Ni:0.54 -* Te::0.050 " flaky 11.1 13.1 59 2.4 1.6 0.46 Ti:0.18 - Sn:0.022 " " 7.6 12.5 60 3.3 2.8 0.41 Nb:0.20, Ta:0.07, - S:0.020 " sphe- 12.4 14.8 Hf:0.08 roidal 61 3.4 3.0 0.53 Cu:0.16, Mo:0.17 -* Al:0.041, As::0.006 " flaky 13.0 13.2 TABLE 3 (Cont'd)
Fe-Base Alloy Composition (wt%) Graphite First Group of Second Group of Magnetic Prop- Magnetic Prop- Third Group of Fe+ Volume Magnetic Sample erty lmproving erty lmproving Magnetic Property lmpu- Ratio Flux # No. Si C Mn Components Components lmproving Components rities Shapa (%) (10-6 Wb) 62 3.2 2.4 0.52 W:0.24, Re:0.08 -* As:0.006, Te:0.006, bal. sphe- 11.1 15.1 Su:0.008 roidal 63 2.9 3.6 0.45 Ni:0.55 Mg:0.015 Bi:0.073 " " 14.6 15.3 64 3.3 2.7 0.47 Cr:0.31, Ni:0.44 Ce:0.05, Ca:0.02 Al:0.022, Te:0.007 " " 12.1 15.5 65 3.1 2.2 0.45 Ti:0.22, Cu:0.15, Mg:0.011 Sb:0.006, Se:0.009, " " 10.5 15.8 No:0.19, Hf:0.10 Ce:0.03, Ca:0.02 Sn:0.007, S::0.006 7 2.7 - - - - - " - - 11.2 8 3.1 - - - - - " - - 11.5 9 3.8 - - - - - " - - 11.8 *: Added as inoculants for graphite spheroidization but undetectable by analysis.
EXAMPLE 4
According to the procedures employed in Example 15 dot core samples Nos. 66 to 79 of the present invention were prepared. These samples were formed of Fe-base alloys having the compositions and graphite volumes shown in Table 4.
Comparative sample cores Nos. 10 to 12 were fabricated by repeating the same procedures except that the melts having the compositions shown in Table 4 were immediately cast and machined to the desired final shape.
Two specimens of each dot core sample were placed side by side in such a manner that the pins on one specimen were in end-to-end registry with those on the other specimen, which was placed in contact with the first specimen with a nonmagnetic material 0.3 mm thick inserted between them. Coils were wound around the pins on one specimen and a rectangular pulsive voltage was applied between the coil terminals under the following conditions:
Frequency: 50 Hz
Terminal voltage: 40 volts
Current applied for: 140 pus Magnetomotive force: 143 ampere-turns (coil
current times coil turns).
The high-frequency AC magnetic characteristics of each sample were evaluated by measuring the magnetic flux, 9, flowing through the pins on the core.
Each of the pins on the dot core had a rectangular cross section with the following dimensions: 9.6 mm (length)XO.17 cm2 (effective cross-sectional area)x2.3 mm (width). Measurement of magnetic flux, , was conducted with a search coil and the data obtained with a waveform analyzer were processed by the formula shown Example 1. The results are shown in Table 4 which also lists the volume ratios of graphite in the matrices of the core samples.
The data in Table 4 shows that the dot core samples Nos. 66 to 79 of the present invention wherein graphite particles were dispersed in a ferrite matrix had much better high-frequency AC magnetic properties than the conventional samples Nos. 10 to 12 which were solely composed of a ferrite matrix. TABLE 4
Fe-Base Alloy Composition (wt%) Graphite Magnetic Property Fe+ Volume Magnetic Sample lmproving lmpu- Ratio Flux # No. Si C Mn Components Mg Ce Ca rities Shape (%) (10-6 Wb) 66 2.8 2.4 0.51 Al:0.006 -* - - bal. spheroidal 10.6 15.1 67 3.1 2.2 0.48 As:0.021 - -* - " " 10.2 15.3 68 3.2 1.8 0.39 Bi:0.094 -* - -* " " 9.2 14.0 69 1.2 2.0 0.46 Se:0.012 -* -* - " " 7.6 14.3 70 3.9 2.1 0.45 Te:0.011 - -* -* " " 10.8 15.4 71 2.4 1.1 0.47 Sn:0.016 - - - " flaky 3.2 13.8 72 3.1 3.8 0.42 Sb:0.010, - - -* " spheroidal 19.3 14.1 Sn:0.007 73 3.0 1.8 0.02 Al: :0.006, -* -* -* " " 8.9 14.5 Bl:0.007 S:0.008 74 3.1 1.9 0.98 Sb:0.007, - - - " flaky 9.2 14.0 Te:0.008, Sn:0.006 TABLE 4 (Cont'd)
Fe-Base Alloy Composition (wt%) Graphite Magnetic Property Fe+ Volume Magnetic Sample lmproving lmpu- Ratio Flux # No. Si C Mn Components Mg Ce Ca rities Shape (%) (10-6 Wb) 75 3.2 1.8 0.40 Al:0.008, 0.18 - - bal. spheroidal 12.4 16.3 Bi:0.007 76 3.0 2.4 0.51 S:0.010 - 0.04 - " " 11.1 16.0 77 2.7 2.2 0.48 Sn:0.015 - - 0.02 " flaky 9.9 14.4 78 2.8 2.0 0.47 As:0.006, 0.02 0.01 - " spheroldal 9.0 16.5 Sb:0.008 Te:0.007 79 3.3 2.1 0.46 Al:0.006, 0.05 0.04 0.07 " " 10.2 17.2 Sb:0.007, Se:0.006, S: :0.008 10 2.7 - - - - - - " - - 12.1 11 3.1 - - - - - - " - - 13.0 12 3.8 - - - - - - " - - 13.3 *:Added as inoculants for graphite spheroidization but undetectable by analysis.
As will be apparent from the foregoing description and data, the high-frequency magnetic core material of the present invention has by far superior high-frequency magnetic characteristics compared with the prior art products and is well capable of meeting the demand for manufacturing dot printers and stepping motors with improved capabilities which can be operated at higher speeds.
Claims (9)
1. A high frequency magnetic core material formed of an iron-based alloy that has: a composition which comprises 1-5% Si and 1-4% C, and optionally at least one element selected from 0.01-1% Mn, 0-0.6% P, 0-1% of at least one of Ti, Nb, Cr, Co, Ni, Cu, Mo, W, Re, Ta and Hf, 0-0.2% of at least one of
Mg, Ge and Ca, and 0-0.1% of at least one of Al, As, Sb, Bi, Se, Te, Sn and S, and the balance being Fe and incidental impurities (all percentages being on a weight basis); and a structure in which 3-20% by volume of graphite is dispersed in a ferrite matrix.
2. A high-frequency magnetic core material according to Claim 1 wherein the C content is within the range of 1-3% by weight.
3. A high frequency magnetic core material according to Claim 1 or Claim 2 wherein the Mn content is.
within the range of 0.051% by weight
4. A high-frequency magnetic core material according to any of Claims 1 to 3 wherein the P content is within the range of 0.01-0.6% by weight.
5. A high-frequency magnetic core material according to any of Claims 1 to 4 wherein at least one of
Mg, Ce and Ca is present in an amount of 0.01-0.2% by weight.
6. A high-frequency magnetic core material according to any of Claims 1 to 5 wherein at least one of Ti,
Nb, Cr, Co, Ni, Cu, Mo, W, Re, Ta, and Hf is present in an amount of 0.05-1% by weight.
7. A high-frequency magnetic core material according to any of Claims 1 to 6 wherein at least one of Al,
As, Sb, Bi, Se, Te, Sn and S is present in an amount of 0.0050.1% by weight.
8. A high-frequency magnetic core material according to any of Claims 1 to 7 wherein said iron-based alloy has a structure in which 5-20% by volume of graphite is dispersed in a ferrite matrix.
9. A high frequency magnetic core material as claimed in Claim 1 substantially as described herein with particular reference to any of Sample Nos. 1 to 79.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6843486 | 1986-03-28 | ||
| JP61296350A JPS6311650A (en) | 1986-03-28 | 1986-12-12 | Magnetic core material made of fe base alloy for high frequency |
| JP62033119A JPS63200504A (en) | 1987-02-16 | 1987-02-16 | Fe alloy magnetic core materials for high frequency |
| JP62033118A JPS63200503A (en) | 1987-02-16 | 1987-02-16 | Fe alloy magnetic core materials for high frequency |
| JP62033120A JPS63200505A (en) | 1987-02-16 | 1987-02-16 | Fe alloy magnetic core materials for high frequency |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8707426D0 GB8707426D0 (en) | 1987-04-29 |
| GB2189257A true GB2189257A (en) | 1987-10-21 |
| GB2189257B GB2189257B (en) | 1989-04-26 |
Family
ID=27521488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8707426A Expired GB2189257B (en) | 1986-03-28 | 1987-03-27 | High-frequency magnetic core material made of iron-based alloy |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2189257B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2405026A (en) * | 2003-08-13 | 2005-02-16 | Alps Electric Co Ltd | Thin film magnetic head including NiPRe alloy gap layer |
| DE102006024414B4 (en) * | 2006-05-24 | 2011-01-13 | Federal-Mogul Burscheid Gmbh | Piston rings and cylinder liners |
| US10662510B2 (en) * | 2016-04-29 | 2020-05-26 | General Electric Company | Ductile iron composition and process of forming a ductile iron component |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4581080A (en) * | 1981-03-04 | 1986-04-08 | Hitachi Metals, Ltd. | Magnetic head alloy material and method of producing the same |
-
1987
- 1987-03-27 GB GB8707426A patent/GB2189257B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4581080A (en) * | 1981-03-04 | 1986-04-08 | Hitachi Metals, Ltd. | Magnetic head alloy material and method of producing the same |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2405026A (en) * | 2003-08-13 | 2005-02-16 | Alps Electric Co Ltd | Thin film magnetic head including NiPRe alloy gap layer |
| GB2405026B (en) * | 2003-08-13 | 2006-08-16 | Alps Electric Co Ltd | Thin film magnetic head including NiPre alloy gap layer |
| US7359148B2 (en) | 2003-08-13 | 2008-04-15 | Tdk Corporation | Thin film magnetic head including NiPRe alloy gap layer |
| DE102006024414B4 (en) * | 2006-05-24 | 2011-01-13 | Federal-Mogul Burscheid Gmbh | Piston rings and cylinder liners |
| US10662510B2 (en) * | 2016-04-29 | 2020-05-26 | General Electric Company | Ductile iron composition and process of forming a ductile iron component |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8707426D0 (en) | 1987-04-29 |
| GB2189257B (en) | 1989-04-26 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940327 |