KR970005880B1 - Ferrite composition - Google Patents

Abstract

Ferrite material consists of; 44~88 m/o Fe2O3,21~28 m/o MgO,4~8 m/o MnO,17~22 m/o ZnO, 2~6 m/o CuO and 0.1~0.4 w/o V2O5. The temperature of sintering is 1,100~1,200 deg. C, and magnetic loss is 130 mw/cc or less at 32KHz,1,000 gauss and 100 deg. C. This ferrite is useful as the core material of yoke for CRT.

Description

Ferrite material

1 is a chart showing the magnetic loss with temperature change for the ferrite material according to the present invention.

FIG. 2 is a plot showing the frequency characteristics for the ferrite material used in FIG.

The present invention relates to an Mg-Mn-Zn-based ferrite material, and more particularly, to a Mg-Mn-Zn-based ferrite material which is sinterable at a low temperature of 1200 ° C or less and has a low magnetic loss.

Mg-Mn-Zn ferrites, Mg-Zn ferrites, Ni-Zn ferrites are used for the yoke coils for cathode ray tubes (CRT) of various electronic devices, but Mn-Zn ferrites have low magnetic losses but low firing costs. The high and very low resistivity causes ringing shape during direct winding, resulting in a firebox deterioration. Ni-Zn ferrite has a high material cost, and recently, Mg-Mn-Zn ferrite is widely used as a material for yoke coils for cathode ray tubes. It is used. In particular, Mg-Mn-Zn-based ferrites have the advantages of cheaper production cost and higher resistivity compared to other yoke materials, allowing vertical coils to be wound directly on cores, but high firing temperatures and low magnetic losses depending on the composition. The problem that other yoke characteristics, such as a curie temperature, declines is shown.

In order to solve the above problems, ferrites having different compositions of Fe ₂ O ₃ , MgO, ZnO, and MnO, which are the conventional ferrite main components for deflection yoke, or added CuO, MoO _3, or Bi ₂ O ₃ to the above-mentioned main components, are already Known. Recently, however, the necessity of display cathode ray tubes requiring high resolution is increasing due to the rapid spread of CAD / CAM. Cathode ray tube which meets the requirements of high speed needs 32Hz to 64Hz, which is higher than the horizontal deflection frequency of 16Hz. The problem arises that ringing shape that causes self-heating increases and image quality deteriorates. Moreover, the above-described conventional ferrite for cathode ray tubes is fired at 1250 ° C. or higher, so that energy consumption is increased due to high firing temperature. Accordingly, there is a demand for a deflection yoke material for cathode ray tubes, which can be fired at a temperature lower than the conventional yoke firing temperature for cathode ray tubes and does not increase self-heating even at a high frequency of 32 Hz or more.

An object of the present invention is to provide a ferrite that can be used as a yoke core material for a negative beam tube which can be fired at a low temperature and has a low magnetic loss.

The purpose of the present invention is stated _{Fe 2 O 3, MgO, ZnO} , in the ferrite composition as a main component MnO CuO ₂ - 6m / o and V ₂ O ₅ 0.1 - the ferrite material of the present invention by the addition of the 0.4w / o Is achieved.

One example according to the present invention is CuO 2-6 m / o and V in a ferrite main component consisting of Fe ₂ O ₃ 44-48 m / o, MgO 21-28 m / o, ZnO 17-22 m / o, MnO 4-8 m / o _It consists of a low-temperature calcinable low magnetic loss ferrite material made by adding ₂ O ₃ 0.1-0.4 w / o.

According to the present invention described above, the addition of CuO and V ₂ O ₅ enables the low temperature baking below 1200 ° C., the self-heating phenomenon appearing at high frequency is eliminated, and the magnetic loss of the conventional Mg-Mn-Zn-based ferrite is greatly reduced. Improved deflection yoke cores could be obtained. In particular, according to the ferrite material of the present invention with the above exemplified composition ratio, the maximum magnetic flux density, coercive force, magnetic loss, sintered density, resistivity, etc. were found to be suitable for high frequency deflection yoke.

According to the experimental results, when the Fe ₂ O ₃ is more than the above-mentioned range, the specific resistance is low, the coercive force Hc and the magnetic loss are increased. If the ZnO is more than the above-mentioned range, the maximum magnetic flux density and Curie temperature are decreased, and if it is less than the above-mentioned range, the coercive force and the magnetic loss are increased. If the copper oxide is more than the above-mentioned range, the overall magnetic properties are poor due to excessive grain growth during sintering. If it is less than the above-mentioned range, the magnetic loss increases and it is impossible to extinguish at low temperature, especially below 1200 ° C.

If the vanadium oxide (V ₂ O ₅ ) is greater than the above-mentioned range, coercive force and magnetic loss increase, while if less than the above-mentioned range, the sintered density (Ds) and the maximum magnetic flux density decrease. Therefore, it was confirmed that the most suitable ferrite material was a material adjusted to the range defined in the above-described example.

According to the present invention, the firing temperature is lower than that of the conventional ferrite materials of the same series, but the firing temperature can be lowered without affecting the intrinsic resistance, which is important for the electromagnetic characteristics, while reducing the production cost due to energy saving. In addition, a ferrite material is obtained in which magnetic loss is greatly reduced at high frequencies.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example

Powders of Fe ₂ O ₃ , MnO, ZnO, MgO, CuO were weighed and mixed according to Table 1, and the mixed raw powder was calcined at 950 ° C. for 2 hours. 0.1 to 0.4 w / o of V ₂ O _{5 was} added to the calcined powder, followed by wet grinding to obtain an average particle diameter of 1.4 μm. Then, 3% polyscale alcohol solution was added to 10 w / o of the total ferrite powder, mixed and then 12ton / A molded article was produced by compression molding at a pressure of cm 2. This sample was baked at 1150 ° C for 4 hours to obtain a ferrite sintered body. For the ferrite sintered body thus produced, electrons such as super magnetic permeability (μi), maximum magnetic flux density (Bm), coercive force (Hc), magnetic loss (Core Loss), sintered density (Ds), specific resistance (ρ) and Curie temperature (Tc) The miracle properties were measured and shown in Table 1.

FIG. 1 shows the magnetic losses for M2, M8 and M6 according to the temperature change. The measurement conditions were 32 ° C 100 ° C and 1000 gauss.

2 is a graph showing the frequency characteristics of the same sample as in FIG. 1, and the measurement conditions were 100 ° C and 1000 gauss.

As can be seen from Table 1 and FIGS. 1 and 2, the sample of the present invention has significantly improved coercive force Hc and core loss at low firing temperature, maximum magnetic flux density Bm, ultra-permeability μ iac, resistivity ρ, The matrix density Ds exhibits excellent characteristics.

Therefore, it was confirmed that the ferrite material of the present invention is suitable as a high-frequency deflection yoke material.

Materials outside the illustrated composition ranges in the present invention have exhibited some problems. In other words, samples M1 and M2 having a large amount of iron oxide, copper oxide and vanadium oxide were both undesirable in terms of electromagnetic characteristics, and sample M3 having a high zinc oxide content had a lower maximum magnetic flux density and Curie temperature. Sample M4, which has a high amount of magnesium oxide and vanadium oxide, has a high coercive force, magnetic loss, low iron oxide content, and high zinc oxide. Sample M8, which contained no copper oxide, had a low sintered density and resistivity, and a small amount of zinc oxide and vanadium oxide showed that coercive force and magnetic loss increased. In addition, sample M11, which had high manganese oxide and low copper oxide, had increased sintering density and magnetic loss, and samples M12-M15 were also out of the defined range and had low electromagnetic characteristics.

Claims (4)

Mg-Mn-Zn ferrite material characterized by adding CuO 2-6m / o and V ₂ O ₅ 0.1-0.4w / o to a ferrite material containing Fe ₂ O ₃ , MgO, MnO, and ZnO as main components . In claims 1, wherein the mixing ratio of the components _{Fe 2 O 3 44 - 48m /} o, MgO 21 - 28m / o, MnO 48m / o, ZnO 17 - 22m / o, CuO 2 -6m / o, V ₂ O ₅ A ferrite material characterized in that from 0.1 to 0.4 w / o. The ferrite material according to claim 1, characterized in that the magnetic loss is not more than 130mw / cc at 32kW, 1000 gauss, 100 ° C. The ferrite material according to claim 1, wherein the firing temperature is 1100-1200 ° C.