JPH0471323B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing a manganese-zinc ferrite composition that can exhibit high performance in noise filters and the like. Conventional technology Malfunctions caused by noise, etc. are seen as a problem in electronic equipment that requires high reliability, such as precision control equipment.
Electronic components have been developed to reduce the influence of this noise. Known examples of these electronic components include noise filters, line filters, and the like, which use manganese-zinc ferrite, which has a relatively high magnetic permeability among ferrite magnetic materials, as a magnetic material. These filters are made of capacitors and ferrite cores.
It consists of an LC filter, and is inserted into the power line of electronic equipment to attenuate noise that enters from the outside, such as the power supply, to reduce the effect of noise on electronic equipment. Among these various noises that invade from the outside, it is important to attenuate the noise with a large E・T product [product of pulse voltage (E) and pulse width (T)], which has a large influence. The desirable magnetic properties that a ferrite magnetic core should have are those that are difficult to be saturated by external magnetic fields, that is, the saturation magnetic flux density (Bs) is large, and the difference between the saturation magnetic flux density (Bs) and the residual magnetic flux density (Br) is (ΔB) is desired to be large, and for this reason as well, manganese-zinc ferrite materials are attracting attention as preferable. The conventional manufacturing method for such a manganese-zinc-based ferrite magnetic core consists of main raw materials consisting of oxides or carbonates such as Fe, Mn, and Zn, and V, Bi, Mo,
Oxides and carbonates of Cu, Si, Ca, B, Sn, Ta, etc.
Auxiliary raw materials such as chloride or fluoride are weighed and blended in appropriate proportions, water is added to this as a starting raw material, and the mixture is stirred using a mixer such as a ball mill or attritor. After thoroughly mixing each of the above ingredients, dehydrate and dry, and then
Heat treatment is performed at a temperature range of 980°C, a so-called pre-firing process. This pre-calcined material is again ground together with water using a grinder such as a ball mill or an attritor until the average particle size becomes approximately 1.0 to 1.5 μm. A binder made of an organic compound, etc. is added to the mixed powder thus obtained, and the mixture is granulated.The resulting granules are filled into a mold of an appropriate shape and pressurized to form a predetermined shape. Form into shape. This molded product is 1300
Main firing is performed at a temperature of ~1400℃ for several hours. After this, the product is processed by surface polishing and other processing depending on the intended use. For example, the main component obtained in this way
_{Fe2O3 50-53} mol%, _MnO2 24-34 mol%,
The magnetic properties of a manganese-zinc ferrite magnetic core with a composition ratio of 16 to 23 mol% ZnO include an initial magnetic permeability of μ5000 to 7000 (measured value at 10 KHz), and a relative loss coefficient.
tanδ/μi<40×10 ^-6 (measured value at 100KHz), saturation magnetic flux density Bs4400Gauss approximately, residual magnetic flux density
Br is about 1000 Gauss, the Curie temperature is about 130 to 150°C, and the difference ΔB between Bs and Br is about 3400 Gauss. Problems to be Solved by the Invention As mentioned above, the conventional manganese-zinc ferrite magnetic core has a ΔB of only about 3400 Gauss, and noise filters and line filters using such a magnetic core have poor noise absorption. There was a problem in that it was not possible to satisfy the requirement of high absorbency to attenuate noise with a large E·T product due to insufficient absorption. An object of the present invention is to provide a method for producing a manganese-zinc ferrite composition that can increase ΔB. Means for Solving the Problems In order to solve the above problems, the present invention provides (a) CaCo ₃ , (b) V ₂ O ₅ , H ₃ BO ₃ , Bi ₂ O ₃ ,
A mixture containing at least one selected from the group of MoO ₃ , B ₂ O ₃ , and CuO is calcined and then pulverized, and the powder obtained by this pulverization is mixed with (c) Fe ₂ O ₃ , MnO ₂ ,
A material obtained by mixing with a mixed powder containing ZnO, comprising (a) 0.03 to 3.0 mol% of CaCo ₃ , (b) V ₂ O ₅ , H ₃ BO ₃ , Bi ₂ O ₃ , MoO ₃ , _{B2O3 ,}
0.01 at least one selected from the group of CuO
~1.0 mol%, (c) Fe ₂ O ₃ 50-53 mol%, MnO ₂ 24-34 mol%,
An object of the present invention is to provide a method for producing a ferrite composition, which comprises a step of firing a ferrite material containing a material composition consisting of 16 to 23 mol% of ZnO. Effect As mentioned above, after pre-calcining components (a) and (b),
Since this was crushed and mixed with the main raw material (c) and then fired, CaO was efficiently segregated at the grain boundaries of the particles made of the main raw material, thereby reducing loss and reducing the residual magnetic flux density Br. considered to be a thing. If the content of component (c) in the main raw material exceeds the above range, both the saturation magnetic flux density Bs and the residual magnetic flux density Br will become high,
If the difference ΔB between these becomes small, or conversely if the component (c) in the main raw material decreases too much, the magnetic permeability μ will drop significantly, and the high magnetic permeability property of the manganese-zinc ferrite will be lost. The sintering temperature does not increase, the growth of crystal grains is promoted, and the saturation magnetic flux density is reduced.
Bs decreases and ΔB decreases. Examples Next, examples of the present invention will be described. Example 1 First, powders of 75.1 g of CaCO ₃ with an average particle size of 5.4 μm and 45.5 g of V ₂ O ₅ with an average particle size of 8.2 μm were mixed in a mortar, and this mixture was transferred to a platinum crucible and heated in a high frequency induction furnace.
Heated at 1000°C for 15 minutes. After cooling to room temperature, the mixture is taken out of the furnace,
The mixture was ground for 2 hours in a vibrating mill consisting of an iron container and iron media to obtain a mixed powder with an average particle size of 1.2 μm. This is used as an auxiliary raw material. Separately, 1002.3 g of Fe ₂ O ₃ (52.3 mol%
(equivalent) and 289.1 g (equivalent to 27.7 mol%) of MnO ₂
A main raw material consisting of 195.4 g (equivalent to 20.0 mol%) of ZnO was prepared, and 14.47 g of the auxiliary raw material obtained above was prepared.
(equivalent to 1 mol % based on the main raw material) and an amount of water suitable for mixing these powders were mixed for 2 hours in a ball mill consisting of an iron container and iron balls. After this time, the mixture was removed and dried. This mixed powder was held at 900° C. for 2 hours to perform temporary firing. Then, the calcined mixture and water were pulverized for 5 hours in a ball mill consisting of an iron container and iron balls in the same manner as above, and then dehydrated and dried to obtain ferrite powder. The ferrite powder thus obtained contains polyvinyl alcohol (PVA) as a binder,
Glycerin and water were added as plasticizers, the mixture was granulated, formed into a toroidal shape, and fired at 1300°C for 3 hours to obtain a sintered ferrite magnetic core with an outer diameter of 23 mm, an inner diameter of 17 mm, and a thickness of 7 mm. A copper wire with a wire diameter of 0.3 mmφ whose surface is insulated with formal resin is used as the primary winding around this magnetic core, 60 times.
Wrap it 20 times as a secondary winding, measure the saturation magnetic flux density (Bs) and residual magnetic flux density (Br) using a commercially available B-H loop tracer, and find the difference ΔB between Bs and Br. The results are shown in the column of Example 1 in Table 1. Examples 2 to 4 In Example 1, 0.72g of each auxiliary raw material
Sintered ferrite magnet in the same manner except that the amounts were 2.87g (equivalent to 0.05 mol% of the main raw material), 2.87g (equivalent to 0.2 mol% of the main raw material), and 28.9g (equivalent to 2.0 mol% of the main raw material). Cores were obtained, and the results were measured in the same manner as in Example 1, and the results are shown in the respective columns of Examples 2 to 4 in Table 1. From these results, increasing the amount of auxiliary raw materials added
There is a range in which Br decreases but Bs does not change much, and in this range ΔB tends to increase.
However, the addition amount of auxiliary raw materials is 1 mol% to 2 mol%.
, Bs decreases and ΔB also decreases, indicating that there is a limit to its increasing tendency. For these reasons, the amount of the auxiliary raw material is preferably 0.05 to 4.0 mol% relative to the main raw material. Examples 5 to 9 In Example 1, instead of using 45.5 g of V ₂ O ₅ as one component of the auxiliary raw materials,
A sintered ferrite magnetic core was obtained in the same manner except that 45.5 g of Bi ₂ O ₃ , MoO ₃ , B ₂ O ₃ , H ₃ BO ₃ , and CuO was used, and the results were measured in the same manner as in Example 1. It is shown in the respective columns of Examples 5 to 9 in Table 2. Examples 10 to 12 In Example 1, instead of heating the mixed powder of the auxiliary raw material in a high frequency induction furnace at 1000°C for 15 minutes,
Sintered ferrite magnetic cores were obtained in the same manner except that the heating temperatures were changed to 600°C, 900°C, and 1200°C, respectively, and these were also measured in the same manner as in Example 1. The results are shown in Examples 10 to 12 in Table 3. Shown in the column. From these results, it is preferable that the preliminary firing temperature of the mixed powder of the auxiliary raw material is 600 to 1200°C. Regarding this pre-firing temperature, if it is higher than the temperature at which the above-mentioned auxiliary raw materials vaporize under normal pressure, the composition ratio of the auxiliary raw materials to the main raw material will change, so it is not preferable, but if the pre-calcination is performed under pressure, this vaporization can be prevented. Therefore, the temperature is not limited to the above temperature. Comparative Example In Example 1, the average particle size was 5.4 μm.
9.01 g of CaCO ₃ and 5.46 g of V ₂ O ₅ with an average particle size of 8.2 μm were used as auxiliary powder powder, 1002.3 g of Fe ₂ O ₃ (equivalent to 52.3 mol%), 289.1 g of MnO ₂ (equivalent to 27.7 mol%), and ZnO. of
The compound containing 195.4g (equivalent to 20.0 mol%) is used as the main raw material powder, and these auxiliary raw material powders and the main raw material powder are simultaneously mixed to form a mixed powder (the auxiliary raw material powder is 1 mol% of the main raw material powder). Obtained. This mixed powder was held at 900° C. for 2 hours to perform temporary firing. Next, the pre-calcined mixture and water were pulverized for 5 hours in a ball mill consisting of an iron container and iron balls, and then dehydrated and dried to obtain ferrite powder. Thereafter, this ferrite powder was treated in the same manner as in Example 1 to obtain a sintered ferrite magnetic core, which was also measured in the same manner as in Example 1. The results are shown in the Comparative Example column of Table 1.

【table】

【table】

[Table] Effects of the invention According to the present invention, CaCO ₃ , V ₂ O ₅ , H ₃ BO ₃ ,
A mixture of at least one selected from the group of Bi ₂ O ₃ , MoO ₃ , B ₂ O ₃ , and CuO is pre-fired, and the pulverized powder is mixed with the manganese-zinc ferrite material before main firing. Therefore, the residual magnetic flux density (Br) of the ferrite magnetic core of the fired body can be reduced without reducing its saturation magnetic flux density (Bs), and as a result, the difference ΔB between the two can be increased. Noise filters and line filters using such ferrite magnetic cores have high noise absorption properties, and can satisfy the requirement for high absorption properties that can remove noise with a large E・T product, and can eliminate interference caused by noise from electronic equipment. can be eliminated and the function can be better realized.

Claims (1)

[Claims] 1 (a) CaCo ₃ , (b) V ₂ O ₅ , H ₃ BO ₃ , Bi ₂ O ₃ ,
A mixture containing at least one selected from the group of MoO ₃ , B ₂ O ₃ , and CuO is calcined and then pulverized, and the powder obtained by this pulverization is mixed with (c) Fe ₂ O ₃ , MnO ₂ ,
A material obtained by mixing with a mixed powder containing ZnO, comprising (a) 0.03 to 3.0 mol% of CaCo ₃ , (b) V ₂ O ₅ , H ₃ BO ₃ , Bi ₂ O ₃ , MoO ₃ , _{B2O3 ,}
0.01 at least one selected from the group of CuO
~1.0 mol%, (c) Fe ₂ O ₃ 50-53 mol%, MnO ₂ 24-34 mol%,
1. A method for producing a ferrite composition, comprising the step of firing a ferrite material containing a material composition consisting of 16 to 23 mol% of ZnO.