KR20030028989A - Soft magnetic core with low core-loss manufactured with permalloy alloy powder - Google Patents

Abstract

The present invention relates to a low loss soft magnetic core made of a permalloy alloy powder, and more particularly, to produce a low loss soft magnetic core having low magnetic loss due to a permalloy powder composed of 38 to 48% of Ni by weight and a residual amount of Fe. It relates to a low loss soft magnetic core made of a permalloy alloy powder.

To this end, the present invention provides a low loss soft magnetic core made of permalloy alloy powder, characterized in that by weight, 38 to 48% nickel (Ni) and the remaining amount is made of iron (Fe).

As described above, the low loss soft magnetic core made of the permalloy alloy powder according to the present invention has an effect of reducing core loss and reducing manufacturing cost compared to the permalloy of the conventional composition.

Description

SOFT MAGNETIC CORE WITH LOW CORE-LOSS MANUFACTURED WITH PERMALLOY ALLOY POWDER}

The present invention relates to a low loss soft magnetic core made of a permalloy alloy powder, and more particularly, to produce a low loss soft magnetic core having low magnetic loss due to a permalloy powder composed of 38 to 48% of Ni by weight and a residual amount of Fe. It relates to a low loss soft magnetic core made of a permalloy alloy powder.

In general, typical soft magnetic metal core materials currently used include permalloy (Ni-Fe alloy), sendust (Fe-Si-Al alloy), silicon steel (Fe-Si alloy), and the like. It is relatively expensive compared to steel, but due to its excellent soft magnetic properties, it is widely used for switching mode power supplies (SMPS) such as small appliances, notebook PCs, and portable communication devices.

Commercialized permalloy can be broadly divided into Fe-Ni-based permalloy and Fe-Ni-Mo-based permalloy (MolyPermalloy; hereinafter referred to as 'MP'). MP has a high permeability, low magnetic loss, and Fe-Ni-based permalloy has a high saturation magnetic flux density value, and thus has an excellent DC overlapping characteristic. The conventionally used Fe-Ni-based permalloy is a 50 permalloy having a Ni composition of 48 to 52% and a 78 permalloy having a Ni composition of 78 to 80%. It is mainly used as -Ni-based permalloy.

The above two compositions are used as Fe-Ni-based permalloy because the crystal anisotropy and the magnetostriction constants are almost the minimum in the composition of 48 to 52% and 78 to 80% of Ni, indicating high permeability. However, these compositions used in the past have been applied to the plate and bulk, Fe-Ni-based permalloy currently used as a metal powder core material Ni is 48 to 52%, in the case of Fe-Ni-based permalloy Ni composition of 40 The lower the Ni content in the range of -50%, the higher the magnetic anisotropy constant, but the smaller the magnetostriction constant, the closer to zero, and the lower the resistivity Ni composition, which can reduce magnetic core loss, decreases over 48%. There is this.

In order to solve the above problems, the present invention provides a low-loss soft magnetic core made of permalloy alloy powder, characterized in that by weight, 38 to 48% nickel (Ni) and the remaining amount is made of iron (Fe) Manufactured with permalloy alloy powder that can reduce manufacturing cost by increasing quality factor (Q) value of magnetic core material expressed by (reactance / total loss) by reducing low magnetic core loss and reducing Ni content which is expensive compared to Fe The purpose is to provide a low loss soft magnetic core.

1 is a process flow diagram illustrating a process for producing a low loss soft magnetic core made of a permalloy alloy powder.

In order to achieve the above object, the present invention is to provide a low-loss soft magnetic core made of permalloy alloy powder, characterized in that by weight, 38 to 48% nickel (Ni) and the remaining amount is made of iron (Fe). do.

Hereinafter, the present invention will be described in more detail.

1 is a process flow diagram showing a method for producing a permalloy alloy powder for producing a low loss soft magnetic core according to the present invention and a process for producing a soft magnetic core using the same.

As shown in FIG. 1, in the preparation of the permalloy powder of the present invention, Fe and Fe-Ni alloys or Fe and Ni are melted so as to have a composition of 38 to 48% by weight of Ni and a residual amount of Fe, and N2, He, Permalloy powder is prepared by injecting one or two or more of the Ne, Ar, Kr, Xe and Rn gases or water.

Subsequently, the manufactured powder is mechanically processed into a horizontal mill, an attribution mill, a rod mill, and the like, which are ball mill processes. Through such mechanical processing, alloy powder is pulverized or stress is applied to the alloy powder to make it easier to recrystallize during heat treatment, so that powders having excellent soft magnetic properties can be obtained at relatively low heat treatment temperatures compared to powders not subjected to mechanical processing. have. In addition, by going through such a mechanical processing process, it is possible to improve the moldability by making spherical powder having poor moldability into powder of irregular shape when forming cores using alloy powder.

Next, the permalloy powder subjected to mechanical processing as described above is subjected to heat treatment in a hydrogen or nitrogen, mixed gas atmosphere of nitrogen and hydrogen and nitrogen at a temperature of 700 to 1000 ° C. for 4 to 15 hours. This powder heat treatment removes the internal stress of the mechanically processed alloy powder and recrystallizes it, and shearing occurs between the hardened powder and the insulating layer by mechanical processing during compression molding of the soft magnetic core using the alloy powder. The purpose is to reduce what you do.

Permalloy powder cores having low magnetic loss can be manufactured by using the permalloy powder obtained through the preparation of the powder by the spraying method, mechanical processing, and heat treatment.

In the preparation of the permalloy powder core of the present invention, a permalloy powder composed of 38 to 48% of Ni and a residual amount of Fe in a weight ratio is prepared, and 0.1 to 4.0% by weight of mixed ceramic is added to the prepared powder and divided into one or two to four times. Coating. The mixed ceramic is a mixture of water glass (Sodium Silicate) and an aqueous solution based on talc and kaolin.

Insulating coating mixed powder is formed into a core having a desired shape by using a press in a molding die, in which Zn, in order to reduce friction between the molding die and the compacted compact and powder particles. Up to 1% of a lubricant, such as ZnS or zinc-stearate, will be added.

Next, in order to remove residual stress and strain in the molded core, heat treatment is performed in hydrogen or nitrogen, mixed gas atmosphere of hydrogen and nitrogen for about 20 to 120 minutes at a temperature range of 500 to 800 ° C. To prepare. The heat treatment temperature and time are limited as described above to completely remove residual stress and obtain good soft magnetic properties without destroying the insulating layer of the alloy powder.

Next, after heat-treating the core molded as described above, permalloy powder core is prepared by protective coating a polyester or epoxy resin or the like on the core surface in order to protect core properties from moisture and air.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

Example 1

As weight%, Ni 38% (Inventive material 1), 41% (Inventive material 2), 45% (Inventive material 3), 47% (Inventive material 4), 49% (Comparative Material 1), 52% (Comparative) 2) After preparing 6 kinds of permalloy powders consisting of residual amount Fe to -140mesh (106µm or less) by nitrogen injection method, a ball mill was performed for 8 hours and a nitrogen atmosphere at 860 ° C. for 5 hours. Heat treatment for

Subsequently, an insulation coating was performed once with 0.25 wt% of mixed ceramics, and 0.3 wt% of zinc-stearic acid was added as a molding lubricant to form an annular core having an outer diameter of 27 mm, an inner diameter of 14.7 mm and a height of 11.2 mm, under a nitrogen atmosphere of 660. Prepared by heat treatment at 1 ℃.

After winding 36 times of the enameled copper wire, the alternating voltage of frequency 100 Hz and voltage 1V was applied, and the inductance L and the quality factor Q were measured using a precision LCR meter. In addition, the DC overlapping characteristics were examined by measuring the change of permeability while changing the DC current. The core loss was measured by B-H analyzer. The primary and secondary windings were measured 15 times at a frequency of 50 Hz and magnetic flux density of 1000 Gauss.

Inductance (L), quality factor (Q), DC overlapping characteristics and core loss of the prepared soft magnetic cores were measured and the results are shown in Table 1.

Soft magnetic properties required for magnetic core materials are high quality factor, excellent DC overlapping characteristics, and low core loss. As can be seen from Table 1, in the case of Inventive Materials 1 to 4, the core loss is low and a high quality factor can be obtained as compared with the comparative material. The higher the permeability of the same soft magnetic material, the lower the quality factor and the higher the core loss. However, the invention material has a higher quality factor and lower the core loss despite the higher permeability than the comparative material. Therefore, it can be seen that the present invention exhibits better soft magnetic properties than the conventional comparative material.

Example 2

As a weight percent, alloy powder consisting of 43% of Ni (inventive material 5), 46% of Ni (inventive material 6), 50% of Ni (comparative material 3), and remaining amount of Fe, -325mesh (up to 45 µm) by nitrogen injection method After the preparation to the size, the ball mill was carried out for 8 hours, and heat-treated for 5 hours at 900 ℃ under a nitrogen atmosphere. Subsequently, two insulation coatings were performed with 0.2 wt% of mixed ceramics, and 0.3 wt% of zinc-stearic acid was added as a molding lubricant to form a cyclic core having an outer diameter of 27 mm, an inner diameter of 14.7 mm and a height of 11.2 mm, under a nitrogen atmosphere at 600 ° C. It was prepared by heat treatment for 1 hour at. Core test was carried out in the same manner as in Example 1, the results are shown in Table 2.

In the case of Example 2, the particle size of the powder is smaller than that of Example 1 and the amount of the insulating coating is large, so that the overall permeability is low, the quality factor is high, and the core loss is low. As can be seen from Table 2, the present invention material has a higher quality factor and a lower core loss than the comparative material as in Example 1.

Example 3

As the weight%, alloy powders composed of Ni 40% (Inventive material 7), Ni 42% (Inventive material 8), Ni 47.5% (Inventive material 9), Ni 50% (Comparative material 3), and the remaining amount Fe were used After preparing to -140 ~ + 325mesh (45 ~ 106㎛) size, the ball mill was carried out for 5 hours, and heat-treated at 750 ℃ under nitrogen atmosphere for 12 hours. Subsequently, two insulation coatings were performed with 0.15% by weight of mixed ceramics, and 0.3% by weight of zinc-stearic acid was added as a molding lubricant to form an annular core having an outer diameter of 27 mm, an inner diameter of 14.7 mm, and a height of 11.2 mm, and at 700 ° C in a nitrogen atmosphere. It was prepared by heat treatment for 30 minutes at. Core test was carried out in the same manner as in Example 1, the results are shown in Table 3.

As a result of Example 3, although the permeability is higher than those of Examples 1 and 2, the quality factor is low and the core loss is high. However, the present invention showed higher quality factor and lower core loss than the comparative material.

As described above, according to the low-loss soft magnetic core made of a permalloy alloy powder of 38 to 48% of nickel (Ni) and the remaining amount of iron (Fe) according to the present invention, core loss is reduced compared to the permalloy of the conventional composition. Therefore, the manufacturing cost can be reduced.

Claims (1)

A low loss soft magnetic core made from a permalloy alloy powder, wherein the weight percentage is 38 to 48% nickel (Ni) and the remaining amount is iron (Fe).