CN101381227A

CN101381227A - Mn-Zn ferrite

Info

Publication number: CN101381227A
Application number: CNA2008101561830A
Authority: CN
Inventors: 西垣诚
Original assignee: KUNSHAN NICERA ELECTRICAL APPLIANCE CO Ltd
Current assignee: KUNSHAN NICERA ELECTRICAL APPLIANCE CO Ltd
Priority date: 2008-10-06
Filing date: 2008-10-06
Publication date: 2009-03-11

Abstract

The invention relates to mangan-zinc ferrite, which is characterized in comprising primary components and secondary components, wherein the primary components comprise 55.0 to 59.0 mol percent of Fe2O3, 4.0 to 9.0 mol percent of ZnO, and the balance of MnO, the secondary components comprise 0.002 to 0.02 weight percent of SiO2, 0.01 to 0.2 weight percent of CaO, 0.01 to 0.2 weight percent of Nb2O5, 0.01 to 4.0 weight percent of NiO, and 0.01 to 0.8 weight percent of Sb2O3. The mangan-zinc ferrite is applicable to chokes for power supplies, achieves a high saturation magnetic flux density of more than 470mT at a high temperature of 100 DEG C and minimum loss at a temperature below 80 DEG C, and low loss loss than 600kW/m<3>. In addition, the mangan-zinc ferrite has stable heating generation property due to small decay of DC superimposition at a high temperature.

Description

Mn-Zn ferrite

Technical field

The present invention relates to a kind of ferrite, specifically relate to a kind of Mn-Zn ferrite that is applicable to the choking coil that on power supply, uses, under the high temperature about 100 ℃ loss less, and it is less to have an overlapping characteristic decay of high saturation magnetic flux density, direct current.

Background technology

In recent years, be accompanied by the small portableization of electric mechanical and highly integrated, in the superpowerization that requires to be used for the supply lead that electric power supplies with, the high efficiency of circuit is also integral.But because the big electric currentization of the integrated and supply circuit of accessory can be generated heat around the circuit, at this moment can employed choking coil guarantee that its original performance is particularly important with regard to what show on the power supply.Particularly nearest, under environment for use temperature (near the 100 ℃) condition of supply lead, high saturation magnetic flux density and low-loss material are by extensively requirement.But existing material behavior instability, the overlapping characteristic of the rectilinearity of initial magnetization curve and direct current is bad, and particularly at high temperature, the overlapping characteristic decay of direct current is bigger, the loss height, saturation magnetic flux density reduces.

Summary of the invention

In order to overcome the above problems a little, the object of the present invention is to provide and a kind ofly at high temperature still can keep stable properties, particularly reduce the decay of the overlapping characteristic of direct current down, in the deterioration of suppressor loss, keep the Mn-Zn ferrite of high saturated flux density in hot conditions (about 100 ℃).

For achieving the above object, the present invention is achieved by the following technical solutions:

A kind of Mn-Zn ferrite is characterized in that comprising principal constituent and minor component, and described principal constituent is the Fe of 55.0～59.0mol% ₂O ₃, 4.0～9.0mol% ZnO, residue for MnO; Minor component is the SiO of 0.002～0.02wt% ₂, the CaO of 0.01～0.2wt%, the Nb of 0.01～0.2wt% ₂O ₅, the NiO of 0.01～4.0wt%, the Sb of 0.01～0.8wt% ₂O ₃

Aforesaid Mn-Zn ferrite is characterized in that Fe in the described principal constituent ₂O ₃For 58.2mol%, ZnO are that 6.0mol%, MnO are 35.8mol%; SiO in the minor component ₂For 0.005wt%, CaO are 0.08wt%, Nb ₂O ₅For 0.03wt%, NiO are 2.5wt%, Sb ₂O ₃Be 0.2wt%.

Aforesaid Mn-Zn ferrite is characterized in that the minimum value of its loss in 20 ℃～120 ℃ is more than 80 ℃ when 100kHz-200mT.

Aforesaid Mn-Zn ferrite is characterized in that the minimum value of described loss, when 100kHz-200mT, at 600kW/m ³Below.

Aforesaid Mn-Zn ferrite, when it is characterized in that its saturation magnetic flux density is 100 ℃ more than 470mT.

The invention has the beneficial effects as follows: Mn of the present invention-Zn ferrite is applicable to the choking coil that uses on power supply, be more than the 470mT, form the temperature of loss minimum value in the saturation magnetic flux density under 100 ℃ the high temperature also more than 80 ℃, at this moment, loss also takes into account 600kW/m simultaneously ³Following low loss characteristic.In addition, because the decay of the direct current overlapping characteristic of Mn-Zn ferrite under hot conditions is little, so the characteristic that on the heating problem that brings owing to the highly integrated and big electric currentization of electronic equipments, just can play stably.

Description of drawings

Fig. 1 is the velocity of variation demonstration figure of embodiments of the invention 8 and the direct current overlapping characteristic of comparative example 2 under 100 ℃ of conditions.

Embodiment

Below in conjunction with specific embodiment the present invention is done concrete introduction.

According to composition requirement shown in the table 1, highly purified ferric oxide, manganese oxide, zinc oxide are measured, mix, then according to the pre-burning 2 hours in atmosphere of 950 ℃ condition.Afterwards, the SiO that in the pre-burning raw material, adds 0.005wt% respectively ₂, the CaO of 0.08wt%, the Nb of 0.03wt% ₂O ₅NiO, Sb with ratio shown in the table 1 ₂O ₃, and pulverize with sand mill, reach 1.5 μ m until grain size of micropowder.Then, add polyvinyl alcohol in chippy powder the inside and carry out granulation, the granulated pellet that obtains is configured as the annular of external diameter 24mm, internal diameter 19mm, high 10mm.Afterwards, in sintering process, on one side the oxygen concentration under the peak temperature condition is controlled, guarantee that it lowers the temperature burn till 4 hours under 1340 ℃ of conditions after more on one side, just obtained sintered sample.And then on the sintered sample that obtains, carry out spiral (3Ts, a secondary 3Ts), and power loss (25～120 ℃ in frequency 100kHz, maximum flux density 200MT, mensuration temperature field) is measured with B-H/Z analyser.And also the saturation magnetic flux density under maximum magnetic flux circle 1194A/m condition is measured.Embodiment 8 shown in Figure 1 and comparative example 2 are by after using this raw material to make choking coil and carrying out the mensuration of the overlapping characteristic of direct current of 100 ℃ of conditions, try to achieve with respect to direct-current biasing (hereinafter to be referred as Idc) 0mA the time the velocity of variation of inductance value (LO).Mensuration is to the inductance value mensuration of Idc=0mA and the mensuration of the inductance value of Idc seal added-time being carried out with LCR table (HP She System 4284A) under the condition of 1kHz, 10mA, spiral 100Ts.In addition, the velocity of variation of inductance value is inductance value (the LO) * 100[% during according to (inductance value (L) of the inductance value during Idc=0mA (LO)-Idc seal added-time)/Idc=0mA] formula calculate.Saturation magnetic flux density, loss minimum value under 100 ℃ of conditions are as shown in table 1.What Fig. 1 represented is the velocity of variation of the L of embodiment 8 and the direct current overlapping characteristic of comparative example 2 under 100 ℃ of conditions.

Table 1

As shown in table 1, in the middle of the composition of embodiment 1-9, can draw the loss minimum value is 600Kw/m in temperature in time more than 80 ℃ ³Following low-loss result.Meanwhile, under 100 ℃ condition, saturation magnetic flux density has also reached the above high numerical value of 470mT.

The Fe of comparative example 1 ₂O ₃Content higher, in comparative example 1,, thereby cause saturation magnetic flux density low because the increase of loss, to burn till density low.In comparative example 2, the saturation magnetic flux density under 100 ℃ of conditions is low, in comparative example 3,4, and the Sb that contains ₂O ₃Exceeded under the scope situation of the present invention, loss increases, saturation magnetic flux density is low.

Essentially consist is restricted to: Fe ₂O ₃: 55.0～59.0mol%, ZnO:4.0～9.0mol% remain and are MnO.When in above-mentioned principal constituent, adding the NiO of specified amount, the temperature of loss minimum value is set in more than the actual actuation temperature of choking coil (generally being more than 80 ℃), by studies have shown that loss in this temperature range is less, Curie temperature is very high (more than 200 ℃), even saturation flux density also can reach more than the 470MT under the high-temperature condition, and the decay of the overlapping characteristic of direct current is less.

When adding above-mentioned essentially consist, also added SiO as minor component ₂, CaO, Nb ₂O ₅, NiO, Sb ₂O ₃

Pass through SiO ₂, CaO coexistence can improve the ratio opposing on a boundary, reduce the loss of eddy current.Nb ₂O ₅And SiO ₂, CaO separates out from grain circle together, except forming the anti-mutual-assistance power loss of height reduces, also certain effect arranged aspect the residual flux density reducing.Nb ₂O ₅Can suppress the generation that particle inner air vent and abnormal grain are grown up, make crystalline particle form the fine shape of homogeneous reaching stable, and then suppress the deterioration of power loss, and improve saturation flux density and reduce resideual flux density.The temperature curve that NiO can relax magnetic flux density changes, and when improving the saturation flux density of high-temperature area, the temperature by the loss value little finger of toe makes choking coil can realize low-lossization more than actual work temperature in the transformation of temperature end.Sb ₂O ₃By the remarkable sintering characteristic that improves, increase sintered density, in the hope of reaching when improving saturation flux density, obtain when addition be the effect that 0.4wt% can effectively improve power loss when following.If become oxide compound after these minor components burn till, the structure when not considering to add.In addition, so long as added additive before originally burning till, in which workshop section carrying out can be not influential.

When adding minor component outside suitable scope, the remarkable increase of concomitant loss, the increase of relict flux metric density and sintered density low can cause the low of saturation flux density, and then make the magnetism deterioration in characteristics.

As Fig. 1 as can be seen, relative with comparative example, the decay of the overlapping characteristic of direct current in an embodiment reduces, and has possessed the flow condition than strong current.

The foregoing description does not limit the present invention in any form, and all employings are equal to the technical scheme that mode obtained of replacement or equivalent transformation, all drop in protection scope of the present invention.

Claims

1, Mn-Zn ferrite is characterized in that comprising principal constituent and minor component, and described principal constituent is the Fe of 55.0～59.0mol% ₂O ₃, 4.0～9.0mol% ZnO, residue for MnO; Minor component is the SiO of 0.002～0.02wt% ₂, the CaO of 0.01～0.2wt%, the Nb of 0.01～0.2wt% ₂O ₅, the NiO of 0.01～4.0wt%, the Sb of 0.01～0.8wt% ₂O ₃

2, according to the described Mn of claim 1-Zn ferrite, it is characterized in that Fe in the described principal constituent ₂O ₃For 58.2mol%, ZnO are that 6.0mol%, MnO are 35.8mol%; SiO in the minor component ₂For 0.005wt%, CaO are 0.08wt%, Nb ₂O ₅For 0.03wt%, NiO are 2.5wt%, Sb ₂O ₃Be 0.2wt%.

3, Mn according to claim 1-Zn ferrite is characterized in that the minimum value of its loss in 20 ℃～120 ℃ is more than 80 ℃ when 100kHz-200mT.

4, Mn according to claim 3-Zn ferrite is characterized in that the minimum value of described loss, when 100kHz-200mT, at 600kW/m ³Below.

5, Mn according to claim 1-Zn ferrite, when it is characterized in that its saturation magnetic flux density is 100 ℃ more than 470mT.