CN105837192A - NiMnZn-based ferrite - Google Patents

Abstract

The invention provides a NiMnZn-based ferrite which can greatly reduce magnetic loss in a frequency around 2MHz so that, compared with the past, an iron core is smaller and minimization of a sensing element can be achieved. Main components include iron oxide of 54-56mol% calculated in terms of Fe<2>O<3>, zinc oxide of 5-8mol% calculated in terms of ZnO, nickel oxide of 2-4mol% calculated in terms of NiO, and residual manganese oxide (MnO). Sub components relative to the main components inclue calcium of 0.08-0.18wt% calculated in terms of CaCo<3), silicon of 0.01-0.007wt% calculated in terms of SiO<2>, titanium of 0.3-0.6wt% calculated in terms of TiO<2>, cobalt of 0.3-0.6wt% calculated in terms of Co<2>O<3>, zirconium of 0.03-0.07wt% calculated in terms of ZrO<2> and stibium of 0.05-0.12wt% calculated in terms of Sb<2>O<3>.

Description

NiMnZn It it is ferrite

Technical field

The magnetic loss that the present invention relates to reduce in the frequency of about 2MHz thus be applicable to the NiMnZn system ferrite of the iron core (core) of the transformator etc. of high frequency switch power.

Background technology

In the sensing element of transformator etc. used in high frequency switch power, from the standpoint of the necessity of the characteristics such as the Curie temperature guaranteed required by its purposes, saturation flux density, it is widely used by Fe as main constituent₂O₃ 50 ~ 56 mol%, ZnO 3 ~ 25 mol%, the MnZn system ferrite of remaining part MnO composition, add various accessory ingredient wherein, be achieved in low lossization.

In above-mentioned MnZn system ferrite, particularly with the addition of the NiMnZn system ferrite of NiO, there is the characteristic that core loss (magnetic loss) is little under the high frequency of more than 2MHz, a kind of NiMnZn system ferrite is proposed in following patent documentation 1, it is characterized in that, contain as accessory ingredient: with CaCO₃Conversion counts the calcium of 800～3000ppm, with SiO₂Conversion counts the silicon of 100～1000ppm and with Nb₂O₅The niobium of conversion meter 520～1000ppm, the average crystallite particle diameter of ferrite crystal grain is 2.1～8.1 μm.

According to following patent documentation 1, there is the NiMnZn system ferrite of above-mentioned composition, as preferred mode, be configured to: be 2700kw/m in 2MHz, 50mT, magnetic loss Pcv that measures at 100 DEG C³Below.

Prior art literature

Patent documentation

Patent documentation 1: Japanese Unexamined Patent Publication 2010-83692 publication.

Summary of the invention

But, according to the requirement of the miniaturization of the most this sensing element, strong hope reduces magnetic loss further.

The present invention is the invention completed in view of above-mentioned condition, it to solve the technical problem that and to be to provide a kind of NiMnZn system ferrite, and it can be greatly decreased the magnetic loss in the frequency of about 2MHz, the most compared with the past make unshakable in one's determination less and can realize the miniaturization of sensing element.

In order to solve above-mentioned technical problem, the invention that claim 1 is recorded is NiMnZn system ferrite, it is characterised in that

Contain as main constituent: with Fe₂O₃The ferrum oxide of conversion meter 54～56 mol%, the zinc oxide of 5～8 mol% in terms of ZnO conversion, the nickel oxide of 2～4 mol% in terms of NiO conversion and remaining part manganese oxide (MnO),

Further, relative to this main constituent, contain as accessory ingredient: with CaCO₃Conversion counts the calcium of 0.08～0.18wt%, with SiO₂Conversion counts the silicon of 0.001～0.007wt%, with TiO₂Conversion counts the titanium of 0.3～0.6wt%, with Co₂O₃Conversion counts the cobalt of 0.3～0.6wt%, with ZrO₂Conversion counts the zirconium of 0.03～0.07wt% and with Sb₂O₃The antimony of conversion meter 0.05～0.12wt%.

Should illustrate, when utilizing the NiMnZn system ferrite described in claim 1 to shape unshakable in one's determination, from the crackle prevented product, breach generation from the viewpoint of, preferably control sintering temperature etc., make sintered density reach 4.8g/cm³Above.

In invention described in claim 1, by adding the Sb of determined scope amount in NiMnZn system ferrite as accessory ingredient, it is sintered at low temperatures, suppresses grain growth, so that initial magnetic permeability diminishes.Therewith, due to resonant frequency shift to high frequency side, such that it is able to the core loss reduced under high frequency.

Additionally, according to the present invention, the result of embodiment is visible as be described hereinafter, the core loss (2MHz-50mT) at 100 DEG C can be reduced to 600 kW/m³Below.This result is compared with the past to be made unshakable in one's determination less and can realize the miniaturization of sensing element.

Here, in the region of room temperature to 150 DEG C, core loss is reduced in order to make magnetic anisotropy diminish, it is necessary that contain as main constituent with Fe₂O₃The nickel oxide of the scope of the ferrum oxide of conversion meter 54～56 mol%, the zinc oxide of 5～8 mol% in terms of ZnO conversion and 2～4 mol% in terms of NiO conversion, remaining part is manganese oxide (MnO).Should illustrate, if nickel oxide not enough 2mol% in terms of NiO converts, then the effect variation that the core loss under high frequency reduces.

Additionally, the Ti in accessory ingredient has the effect of the resistance improved in crystal grain, therefore by adding the amount in above-mentioned scope, it is possible to reduce core loss, but the upper limit is with TiO₂Conversion meter is set to the reason of 0.6wt%.

And then, Ca and Si contributes to the composition of the high resistance of grain boundary, can reduce core loss by the amount in the above-mentioned scope of interpolation.Additionally, for Co, there is due to the specific anisotropy of Co the effect making neticdomain wall stabilisation, the core loss of high frequency can be reduced by the amount in the above-mentioned scope of interpolation.If additionally, with Co₂O₃Conversion meter then cannot fully obtain the effect above less than 0.3wt%, if it exceeds the core loss of 0.6wt% then low temperature range is deteriorated.

Accompanying drawing explanation

Fig. 1 is the chart of the result illustrating embodiments of the invention.

Detailed description of the invention

The ferritic embodiment of NiMnZn system below for the present invention illustrates.

This NiMnZn system ferrite, in the scope of room temperature to 150 DEG C, is reduced levels in order to make magnetic anisotropy diminish by core loss suppression, contains with Fe as main constituent₂O₃The ferrum oxide of conversion meter 54～56 mol%, the zinc oxide of 5～8 mol% in terms of ZnO conversion, the nickel oxide of 2～4 mol% in terms of NiO conversion, and remaining part is made up of manganese oxide (MnO).

And, this NiMnZn system ferrite, as accessory ingredient, contains relative to above-mentioned main constituent: with CaCO₃Conversion counts the Ca of 0.08～0.18wt%, with SiO₂Conversion counts the Si of 0.001～0.007wt%, with TiO₂Conversion counts the Ti of 0.3～0.6wt%, with Co₂O₃Conversion counts the Co of 0.3～0.6wt%, with ZrO₂Conversion counts the Zr of 0.03～0.07wt% and with Sb₂O₃The Sb of conversion meter 0.05～0.12wt%, so that sintered density reaches 4.8g/cm³Above mode is calcined.

According to having the NiMnZn system ferrite of above composition, as described later, the core loss (2MHz-50mT) at 100 DEG C can be reduced to 600 kW/m³Below.

Embodiment

First, weigh the main constituent raw material as main constituent, so that with Fe₂O₃Conversion meter ferrum oxide is 55 moles of %, in terms of MnO conversion, manganese oxide is 36 moles of %, in terms of ZnO conversion, zinc oxide is 6 moles of %, in terms of NiO conversion, nickel oxide is 3 moles of %.

Then, after using ball mill to carry out wet mixed 5 hours the raw material of weighing, roasting 2 hours at 850 DEG C, pulverize with ball mill the most again in an atmosphere.Then, in the powder of gained, raw material as accessory ingredient adds Sb the most as shown in Figure 1₂O₃、Co₂O₃、CaCO₃、SiO₂、TiO₂、ZrO₂, after using PVA to be a granulated into graininess, it is annular (toroidal) with die forming.

Should illustrate, the unit of the addition of the above-mentioned accessory ingredient shown in Fig. 1 is wt%.Then, calcine above-mentioned formed body on 1170 DEG C of following control partial pressure of oxygen limits, make ferrite sintered body.Fig. 1 illustrates test portion obtained as described above core loss Pcv (kW/m under conditions of 2MHz-50mT³) and sintered density d (g/cm³)。

As it is shown in figure 1, according to embodiments of the invention 1～18, it is possible to reach 4.8 g/cm with sintered density³Above mode is calcined, and can reduce the core loss (2MHz-50mT) at 100 DEG C to 600 kW/m³Hereinafter, in described embodiments of the invention 1～18, relative to ferrum oxide, zinc oxide, nickel oxide and manganese oxide as main constituent, contain as accessory ingredient with CaCO₃Conversion counts the Ca of 0.08～0.18wt%, with SiO₂Conversion counts the Si of 0.001～0.007wt%, with TiO₂Conversion counts the Ti of 0.3～0.6wt%, with Co₂O₃Conversion counts the Co of 0.3～0.6wt%, with ZrO₂Conversion counts the Zr of 0.03～0.07wt% and with Sb₂O₃The Sb of conversion meter 0.05～0.12wt%.

Comparatively speaking, in the Sb content comparative example 1～3 less than above-mentioned scope, sintered density is 4.8 g/cm³Below, it is impossible to obtain sufficient sintered density, on the other hand in Sb content exceedes the comparative example 4 of above-mentioned scope, it is known that core loss (2MHz-50mT) reaches 600 kW/m³Above.

In addition, in the comparative example 5 of the not enough above-mentioned scope of content of Co and the comparative example 7 of the not enough above-mentioned scope of content of the comparative example 6 and Ca that exceedes above-mentioned scope and the comparative example 8 exceeding above-mentioned scope, it is known that core loss (2MHz-50mT) all reaches 600 kW/m³Above.

And then, for at the comparative example 13 of the not enough above-mentioned scope of content of the comparative example 11 of the comparative example 9 of the not enough above-mentioned scope of the content of Si and the not enough above-mentioned scope of content exceeding the comparative example 10 of above-mentioned scope, Ti and the comparative example 12 and Zr that exceedes above-mentioned scope and the comparative example 14 that exceedes above-mentioned scope, it is possible to know that core loss (2MHz-50mT) all cannot reduce to 600 kW/m³Below.

From above result of the test, according to the NiMnZn system ferrite of the present invention, reaching 4.8 g/cm with sintered density³In the case of above mode is calcined, the core loss (2MHz-50mT) at 100 DEG C can reduce to 600 kW/m³Below.

Claims (1)

1.NiMnZn system ferrite, it is characterised in that

Contain as main constituent: with Fe₂O₃The ferrum oxide of conversion meter 54～56 mol%, the zinc oxide of 5～8 mol% in terms of ZnO conversion, the nickel oxide of 2～4 mol% in terms of NiO conversion and remaining part manganese oxide MnO,

Further, relative to this main constituent, contain as accessory ingredient: with CaCO₃Conversion counts the calcium of 0.08～0.18wt%, with SiO₂Conversion counts the silicon of 0.001～0.007wt%, with TiO₂Conversion counts the titanium of 0.3～0.6wt%, with Co₂O₃Conversion counts the cobalt of 0.3～0.6wt%, with ZrO₂Conversion counts the zirconium of 0.03～0.07wt% and with Sb₂O₃The antimony of conversion meter 0.05～0.12wt%.