KR20120061359A - NiZnCu FERRITE AND PREPARATION METHOD THEREOF - Google Patents

Abstract

PURPOSE: NiZnCu ferrite and a preparation method thereof are provided to effectively extend the recognition range of an RFID(Radio Frequency Identification) device by maintaining high magnetic permeability and low permeation loss in 13.56MHz band. CONSTITUTION: NiZnCu ferrite comprises, as main components, 47-48mol.% of Fe converted from Fe2O3, 18-28mol.% of Ni converted from NiO, 17-27mol.% of Zn converted from ZnO, and 7-8mol.% of Cu converted from CuO. The NiZnCu ferrite comprises, as additives, 0.3-0.5wt.% of Bi converted from Bi2O3, 0.3-1wt.% of Cr converted from Cr2O3, and 0.5-1wt.% of Co converted from Co3O4 to 100wt.% of the main components.

Description

ＮｉＺｎＣｕ ferrites and manufacturing method thereof {NiZnCu FERRITE AND PREPARATION METHOD THEREOF}

The present invention relates to NiZnCu ferrite and its manufacturing method which can exhibit high permeability low loss characteristics.

RFID (Radio Frequency Identification) is a technology that can track the whole process from production to sale in a microchip (IC chip) and track it by radio frequency.It can be used for electronic tags, smart tags, electronic labels, and wireless identification. It is an important foundation technology for ubiquitous called.

RFID is widely used in fields such as logistics and warehouse management or mail management as well as mobile equipment such as cellular phones, RFID tags, and contactless IC cards. In particular, in the field of distribution, it is regarded as the next generation recognition technology to replace the bar code used for goods management.

RFID consists of a reader (Read) and a reader (Tag) for providing information, and contains a variety of information in a tag attached to the product, and allows the reader to read this information through the antenna. It is also used in conjunction with information systems in conjunction with satellites or mobile networks.

RFID has a longer recognition distance than barcodes that can only read information within a few centimeters, but when the antenna contacts the reader with the metal plate, the recognition distance tends to decrease.

In order to solve this problem, a method of placing a magnetic sheet having high performance characteristics between the antenna and the metal plate has been proposed. For example, Korean Utility Model Publication No. 2010-5061 discloses an amorphous metal powder, which is an amorphous metal powder (main component: Fe 73.5 at.%, Cu 1 at.%, Nb 3 at.%, Si 13.5 at.%, B). 9 at.%) And CPE as a support material are disclosed to increase the maximum communication distance of the radio wave absorber for the UHF band (433 MHz, 860-960 MHz) RFID system. In addition, magnetic sheets made of metal magnetic powders such as Fe-Si and Fe-Si-Al, magnetic sheets made of ferrite such as NiZn and NiMn, and the like are known.

However, existing magnetic sheets have a low permeability and a high permeability loss in the 13.56 MHz band where RFID is used. For example, in the case of Fe-Si and Fe-Si-Al metal magnetic powders, the magnetic permeability and the loss loss characteristics are inferior to those of NiZn ferrite and NiMn ferrite, and in the case of Fe-Si and Fe-Si-Al metal powders, It is difficult to improve the recognition distance of RFID because it is difficult to implement so that the permeability is more than 50 and the investment loss is less than 0.1.

An object of the present invention is to provide a NiZnCu ferrite for RFID and a manufacturing method thereof having a high permeability and a low investment loss in the 13.56 MHz band.

1. 47-48 mol% of Fe as Fe ₂ O ₃ , 18-28 mol% of Ni as NiO, 17-27 mol% of Zn as ZnO, and 7-8 mol% as Cu as CuO. 0.3 to 0.5 parts by weight of Bi in terms of Bi ₂ O ₃ as additives, and 0.3-1 parts by weight of Cr in terms of Cr ₂ O ₃ , and 0.5 to 0.5 parts of Co ₃ O _{4 in} terms of Co ₃ O ₄ . NiZnCu ferrite containing 1 part by weight.

2. NiZnCu ferrite according to the above 1, wherein the molar ratio of NiO and ZnO is 2: 3 (18 mol%: 27 mol%).

3. In the above 1, NiZnCu ferrite containing Cr 0.3-0.5 parts by weight in terms of Cr ₂ O ₃ .

4. according to the above 1, NiZnCu ferrite Co is contained 0.8-1 parts by weight of Co ₃ O ₄ equivalent.

5.Fe contains 47-48 mol% in terms of Fe ₂ O ₃ , Ni is 18-28 mol% in terms of NiO, 17-27 mol% in terms of Zuga ZnO and 7-8 mol% in terms of CuO An additive containing 0.3 to 0.5 parts by weight of Bi in terms of Bi ₂ O ₃ , Cr of 0.3-1 part by weight in terms of Cr ₂ O ₃ , and 0.5-1 part by weight of Co in terms of Co ₃ O ₄ , A first step of wet mixing; A second step of drying and pulverizing the slurry prepared in the first step; And a third step of calcining the pulverized powder at 800-850 ° C. for 3-5 hours.

6. In the above 5, the drying of the second process is a ferrite manufacturing method that is made for 12-15 hours at 150-200 ℃.

7. In the above 5, the ferrite manufacturing method further comprises a fourth step of wet grinding the calcined powder.

8. The method of 7 above, further comprising the fifth step of drying and pulverizing the pulverized slurry at 150-200 ℃ for 12-15 hours.

The present invention can provide a ferrite having a permeability of 50 or more, preferably 100 or more and an investment loss of 0.1 or less, preferably 0.03 or less in the 13.56 MHz band, and a method of manufacturing the same.

Ferrite of the present invention can easily control the permeability and the loss in the 13.56MHz band by adjusting the content of NiO as the main component and the content of Cr and Co as additives.

The ferrite of the present invention exhibits the above permeability and permeability characteristics in the 13.56 MHz band, thereby effectively improving the recognition distance of the RFID.

The ferrite of the present invention has excellent frequency characteristics relative to the permeability (the existing NiZnCu ferrite has a high permeability of 150 or more and a permeability of less than 0.03 at 15 MHz due to the problem of investment loss), and thus exhibits high frequency characteristics when applied to a chip inductor. It is possible to implement passive components.

Figure 1 shows the permeability distribution of each frequency according to the change in the content of NiO.
2 shows the investment loss distribution for each frequency according to the change in the content of NiO.
Figure 3 shows the permeability distribution by frequency according to the change in the content of Co ₃ O ₄ .
Figure 4 shows the investment loss by frequency according to the change in the content of Co ₃ O ₄ .
Figure 5 shows the RFID recognition distance according to the magnetic permeability when the NiZnCu ferrite powder of the present invention is made of a magnetic sheet.
6 shows the structure of an antenna equipped with a ferrite of the present invention.
7 shows a Passive Test test method.
8 illustrates a reading test test method.

The present invention comprises 47-48 mol% of Fe in terms of Fe ₂ O ₃ , 18-28 mol% of Ni in terms of NiO, 17-27 mol% of Zn in terms of ZnO, and 7-8 mol of Cu in terms of CuO. %, 0.3-0.5 parts by weight of Bi in terms of Bi ₂ O ₃ as an additive, and 0.3-1 parts by weight of Cr in terms of Cr ₂ O ₃ , and 0.5 parts of Co in terms of Co ₃ O ₄ . The present invention relates to NiZnCu ferrite and a method of manufacturing the same, which exhibits excellent characteristics of permeability of 50 or more and investment loss of 0.1 or less in the 13.56 MHz band, thereby effectively improving the recognition distance of RFID.

Hereinafter, the present invention will be described in detail.

The ferrite of the present invention contains Fe, Ni, Zn and Cu as main components. Fe is 47-48 mol% in terms of Fe ₂ O ₃ , Ni is 18-28 mol% in terms of NiO, Zn is 17-27 mol% in terms of ZnO, and Cu is 7-8 mol% in terms of CuO.

NiO and ZnO in the ferrite of the present invention preferably has a molar ratio of 2: 3 (18 mol%: 27 mol%). This is because the permeability and the loss characteristics of the frequency are the best at this molar ratio.

Ni may be included 18-28 mol% in terms of NiO, but in order to achieve high permeability, it is preferable to include 18-23 mol%, and most preferably, 18-20 mol%, and to achieve low investment loss. In order to contain 18-23 mol%, it is preferable to contain it, and it is most preferable to contain 23-28 mol%.

Ferrite of the present invention is based on 100 parts by weight of the main ingredient as 0.3 to 0.5 parts by weight of Bi in terms of Bi ₂ O ₃ , 0.3-1 parts by weight of Cr in terms of Cr ₂ O ₃ and Co in terms of Co ₃ O ₄ 0.5-1 part by weight. In addition to the above main components, the inclusion of the additive of the present invention can easily exhibit the characteristics of permeability of more than 50 and permeability of 0.1 or less in the 13.56 MHz band.

More specifically, the addition of Bi ₂ O ₃ induces grain growth of ferrite, the permeability characteristics are improved through the addition of Cr ₂ O ₃ ferromagnetic material, and the magnetic anisotropy is reduced through the addition of Co ₃ O ₄ . The loss can be improved.

Ferrite of the present invention can exhibit the most desirable permeability and loss characteristics when adjusting the content of Ni to the above range, while adjusting the content of Cr and Co to a certain range.

Cr may be included in the amount of 0.3-1 parts by weight in terms of Cr ₂ O ₃ , Co is 0.5-1 parts by weight in terms of Co ₃ O ₄ , Cr is more preferably included 0.3-0.5 parts by weight in terms of Cr ₂ O ₃ Co is more preferably contained 0.8-1 parts by weight in terms of Co ₃ O ₄ .

Ferrite of the present invention is prepared as follows.

First, Fe ₂ O ₃ , NiO, ZnO, CuO raw materials are weighed, respectively, and then Fe ₂ O ₃ 47-48 mol%, NiO 18-28 mol%, ZnO 17-27 mol%, CuO 7-8 mol% 0.3-0.5 parts by weight of Bi ₂ O ₃ , 0.3-1.0 parts by weight of Cr ₂ O ₃ , and 0.5-1.0 parts by weight of Co ₃ O _{4 based} on 100 parts by weight of these main components, and then wetted with, for example, an attritor, a ball mill, or the like. The process is mixed for at least 6 hours, preferably 20-24 hours. As the raw material powder, other oxides or compounds which become oxides by sintering may be used instead of Fe ₂ O ₃ .

The mixed slurry is then disintegrated after drying at 150-200 ° C. for at least 12 hours, preferably 12-15 hours. The disintegration process follows a conventional method.

The pulverized powder is then calcined for 3-5 hours in the 800-850 ° C. temperature range. Calcination is carried out in air. If the calcination temperature is not in the above range, the crystal structure of the ferrite may not be formed completely, and thus the transmittance and investment loss characteristics may be changed.

The calcined powder is then wet ground for 20-24 hours, such as in a ball mill. Wet grinding by an attritor, ball mill, jet mill or the like is, for example, grinding to 0.8 m or less, preferably 0.1 to 0.4 m, more preferably 0.1 to 0.2 m. Through the grinding process, adjustment of the particle level, removal of necking and improvement of dispersibility of the additive can be achieved.

The milled slurry is then dried and crushed at 150-200 ° C. for 12-15 hours.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example

Example 1-5 and Comparative Example 1-2

Fe ₂ O ₃ (DAE SANG), NiO (IN CO), ZnO (DAE JUNG), and CuO (JUNSEI), which are the main components of the ferrite of the present invention, were weighed as shown in Table 1 below, and the total weight of these contents was 100 weights. For the parts, Bi ₂ O ₃ (JUNSEI), Cr ₂ O ₃ (JUNSEI) and Co ₃ O ₄ (JUNSEI), which are additive components, were also weighed as shown in Table 1, respectively, and then 8 hours in a wet ball mill using distilled water. Mixed.

After mixing was complete, the mixture was dried at 150 ° C. until water was completely removed.

After the drying was completed, it was calcined at 840 ° C. for 3 hours to produce a spinel crystal phase.

The calcined powder was ground in a wet ball mill for 20 hours using distilled water.

After the pulverization was completed, the water was completely removed again at 150 ° C. to prepare a powder.

division Main ingredient (mol%) Additional ingredients (parts by weight) Fe ₂ O ₃ NiO ZnO CuO Bi ₂ O ₃ Cr ₂ O ₃ Co ₃ O ₄ Example 1 48 18 27 7 0.3 0.3 0.7 Example 2 48 24 21 7 0.3 0.3 0.7 Example 3 48 28 17 7 0.3 0.3 0.7 Example 4 48 18 27 7 0.3 0.3 0.5 Example 5 48 18 27 7 0.3 0.3 1.0 Comparative Example 1 48 15 30 7 0.3 0.3 0.7 Comparative Example 2 48 15 30 7 0.3 0.3 -

Test Example

1. Measurement of Permeability and Loss

In order to measure the magnetic properties of the powders prepared in Examples 1-5 and Comparative Examples 1-2, PVA was added by adding about 3 parts by weight based on 100 parts by weight of the powder. The granulated powder was manufactured into a toroidal sintered body having an outer diameter of 18 mm, an inner diameter of 6 mm, and a height of 3 mm, and then the permeability (μ) and the investment loss (Tanδ) were measured.

Permeability (μ) and permeability loss (Tanδ) were measured using an impedance analyzer. The sintered compact density was shown by the apparent density.

The results are summarized in Table 2 and FIGS. 1-4. For reference, FIGS. 1 and 2 show the permeability and the investment loss of Examples 1-3, and FIGS. 3 and 4 illustrate the permeability and the investment loss of Examples 4, 1 and 5. FIG.

division Permeability (μ)
(13.56 MHz) Loss of investment (Tanδ)
(13.56 MHz) Density (g / cm ³ ) Example 1 135 0.02 5.21 Example 2 90 0.02 5.23 Example 3 52 0.02 5.20 Example 4 270 0.1 5.24 Example 5 48 0.01 5.23 Comparative Example 1 320 0.8 5.21 Comparative Example 2 450 1.7 5.20

As shown in Table 2, the ferrite of the present application was significantly lower than the conventional ferrite, the investment loss as a whole, it was confirmed that the permeability is also high within the range that the investment loss is maintained in this way. Among the examples, it can be seen that Example 1 having a molar ratio of NiO and ZnO of 2: 3 shows the best permeability.

In addition, as the content of Co ₃ O ₄ increases within the scope of the present application, the investment loss is significantly lowered, and when it is necessary to significantly reduce the investment loss, it was confirmed that it is preferable to mix more Co ₃ O ₄ .

2. Measurement of recognition distance

In order to check whether the ferrite according to the present invention extends the recognition distance of the antenna, the recognition distance was measured as follows by inserting a ferrite having a permeability of 50 and a ferrite having a permeability of 100 to an antenna having a structure as shown in FIG. 6. As shown in FIG. 5, the ferrite according to the present invention was found to exhibit an excellent recognition distance from a low frequency to a high frequency.

Passive Test (FIG. 7)

In the manual test, the antenna resonant frequency is checked for resonance in the frequency band used, and then the recognition distance test is performed.

Reading test (Fig. 8)

Recognition distance test is conducted with Low, Standard, and High to measure the recognition distance at these three positions.

Claims (8)

Main components include 47-48 mol% of Fe in terms of Fe ₂ O ₃ , 18-28 mol% of Ni in terms of NiO, 17-27 mol% of Zn in terms of ZnO, and 7-8 mol% of Cu in terms of CuO. ,
0.3-0.5 parts by weight of Bi in terms of Bi ₂ O ₃ , 0.3-1 parts by weight of Cr in terms of Cr ₂ O ₃ , and 0.5-1 parts by weight of Co in terms of Co ₃ O ₄ with respect to 100 parts by weight of the main component. NiZnCu ferrite containing.
The NiZnCu ferrite according to claim 1, wherein the ratio of NiO and ZnO is 18:27 mol% (including units).
The NiZnCu ferrite according to claim 1, wherein Cr is contained in an amount of 0.3-0.5 parts by weight in terms of Cr ₂ O ₃ .
The NiZnCu ferrite according to claim 1, wherein Co is contained in an amount of 0.8-1 parts by weight in terms of Co ₃ O ₄ .
100 main component containing Fe 47-48 mol% in terms of Fe ₂ O ₃ , Ni 18-28 mol% in terms of NiO, 17-27 mol% in terms of CuZa ZnO and 7-8 mol% in terms of CuO Wet mixed additives containing 0.3 to 0.5 parts by weight of Bi in terms of Bi ₂ O ₃ , 0.3-1 parts by weight of Cr in terms of Cr ₂ O ₃ , and 0.5-1 parts by weight of Co in terms of Co ₃ O _4. 1st process which makes;
A second step of drying and pulverizing the slurry prepared in the first step; And
Method for producing a ferrite of claim 1 comprising the third step of calcining the pulverized powder at 800-850 ℃ for 3-5 hours.
The method of claim 5, wherein the drying of the second process is performed at 150-200 ° C. for 12-15 hours.
The method of claim 5, further comprising a fourth step of wet milling the calcined powder.
The method of claim 7, further comprising a fifth step of drying and pulverizing the ground slurry at 150-200 ° C. for 12-15 hours.

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