CN105924146A - Wide temperature range nickel-zinc LTCF material for high power multilayer-chip type ferrite devices and preparation method therefor - Google Patents

Abstract

The invention discloses a wide temperature range nickel-zinc LTCF material for high power multilayer-chip type ferrite devices. The main constituent of the LTCF material comprises the following components in the mole percentage: 8mol% to 35mol% of nickel oxide, 9mol% to 35mol% of zinc oxide, 8mol% to 12mol% of cupric oxide and 51mol% to 58mol% of ferric oxide. The present invention also discloses the preparation method of the material. The material has an excellent microscopic structure. The compensation point which shows the position of the peak II is moved below minus 55 degrees Celsius. The ui-T curve between the peak I and peak II is relatively flat. The temperature stability of the material is good. The material meets the requirements of the operational reliability and the environmental suitability of the magnetic property of the high power multilayer-chip type ferrite devices produced by using LTCF multilayer lamination technique under the application environment of high and low temperature in the wide temperature range from minus 55 degrees Celsius to 85 degrees Celsius.

Description

Wide-temperature nickel-zinc LTCF material for high-power multilayer chip ferrite device and preparation method

technical field

The invention relates to the technical field of ferrite materials, in particular to a wide-temperature nickel-zinc LTCF material for high-power multilayer chip ferrite devices and a preparation method thereof.

Background technique

Modern military equipment, weapon systems, aviation, aerospace engineering, etc. have increasingly strict requirements on the volume, weight and performance of electronic systems, especially electronic components and components required by spaceborne, missile-borne, and airborne weapon systems. It is developing in the direction of small, light, thin, high reliability, high performance and high speed. At present, the switching power converter, which is the heart part of the power supply system, needs to be miniaturized and highly reliable. The power type LTCF inductor substrate (that is, the ferrite substrate integrated with power inductors, of which LTCF (LowTemperature Co-fired Ferrite ), that is, low-temperature co-fired ferrite) and chip magnetic power devices (such as micro-magnetic transformers, etc.), are an important step to realize the passive integration of components and the miniaturization, light weight, high performance and high reliability of switching power converters. The key lies in the power type nickel-zinc LTCF material.

At present, the traditional bulk power nickel-zinc ferrite material is not suitable for LTCF process due to high firing temperature (greater than 1100°C), large powder particle size and wide distribution range (D ₅₀ : 3μm～10μm); The conventional power type nickel-zinc LTCF material that has been engineeringly applied in the laminated sheet process technology has low power consumption, low loss when passing high current and high voltage, and low heat generation of the device, so it can be used for devices with strict heat control. High-current inductors, power micro-magnetic transformers, power ferrite substrates for power converters, etc. Under the premise of satisfying the LTCF process, the focus of its formula design is mainly reflected in the realization of key magnetic performance indicators such as high magnetic permeability, low power loss, and sintering temperature of about 900 ° C, while ignoring the wide temperature design of magnetic properties. The temperature characteristic of magnetic properties (permeability μ _i or inductance L) is relatively good in the application temperature range only between -20 and +85°C, and there are generally changes in magnetic properties in high and low temperature environments with a wide temperature range of -55 to +85°C Large, poor temperature stability; resulting in multilayer chip ferrite devices, especially high-power multilayer chip ferrite devices, even through adjusting the device air gap area, number of layers, sintering curve and other methods, there are still high and low temperature In the application environment, the magnetic properties change greatly, the stability is poor, especially the problem of large leakage inductance at low temperature, which seriously affects the reliability of device performance and environmental adaptability (the change rate of inductance L at -55～+85°C is required to be -30% ~+200%).

Contents of the invention

One of the objectives of the present invention is to provide a wide-temperature nickel-zinc LTCF material for high-power multilayer chip ferrite devices to solve the above problems.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows: a kind of wide-temperature nickel-zinc LTCF material for high-power multilayer chip ferrite device, its main component is the following components in molar percentage:

NiO 8mol%～35mol%

ZnO 9mol%～35mol%

CuO 8mol%～12mol%

Fe ₂ O ₃ 51mol%-58mol%.

As a preferred technical solution, an auxiliary component V ₂ O ₅ of 0.3wt%-0.7wt% in mass percentage is also included.

As a preferred technical solution: the LTCF material is LTCF100, LTCF300 or LTCF500.

As a further preferred technical solution, the main component of the LTCF100 material is the following components in mole percent:

NiO 25mol%～32mol%

ZnO 9mol%～14mol%

CuO 8mol%～12mol%

Fe ₂ O ₃ 51mol%-58mol%.

As a further preferred technical solution: the main component of the LTCF300 material is the following components in mole percent:

NiO 18mol%～23mol%

ZnO 16mol%～22mol%

CuO 8mol%～12mol%

Fe ₂ O ₃ 51mol%-58mol%.

As a further preferred technical solution: the main component of the LTCF500 material is the following components in mole percent:

NiO 8mol%～12mol%

ZnO 26mol%～33mol%

CuO 8mol%～12mol%

Fe ₂ O ₃ 51mol%-58mol%.

The inventor of the present invention, through a large number of experimental studies, adopts NiCuZn iron-rich (Fe ₂ O ₃ content > 50mol%) without adding Co formula and controls the content of Zn ²⁺ and Fe ²⁺ to reduce the power loss of the material; at the same time, adopt Higher Cu content formula, adding an appropriate amount of low-melting point V ₂ O ₅ to reduce the sintering temperature and cooperating with the method of wet grinding process to refine powder particles (particle size distribution D ₅₀ <2.5μm), so that the material is fired at about 900°C Afterwards, it has an excellent microstructure (small, uniform and complete grains, few and dispersed internal pores, etc.), a relatively flat μ _i -T curve, and good temperature stability.

The second object of the present invention is to provide a preparation method of the above-mentioned material, the technical solution adopted is: comprising the following steps:

A. Dry mixing: take the main components according to the proportion, mix them evenly after crushing, and obtain the mixture, and the mixing time is 30-60 minutes;

B. Pre-sintering: pre-sintering the mixed material obtained in step A, the pre-sintering temperature is 750-850° C. to obtain the pre-sintered material;

C. Wet grinding: add V ₂ O ₅ in the stated proportion to the pre-sintered material obtained in step B, and carry out wet grinding to control the particle size distribution of the powder material D ₅₀ < 2.5 μm to obtain ultra-fine ferrite particles ; Wet grinding and controlling the appropriate particle size can reduce the sintering temperature.

D. Secondary sintering: The ultra-fine ferrite particles obtained in step C are subjected to secondary sintering at a sintering temperature of 850-910° C. to obtain a finished product.

As a preferred technical solution: step A is to use a high-frequency vibrating mixing system for mixing.

It can make the main component raw material oxides achieve high-speed crushing effect and effectively improve the mixing uniformity of each raw material oxides.

As a preferred technical solution: Step B is carried out in a sintering kiln.

As a preferred technical solution: Step C is carried out in a large-flow circulating sand mill.

The wet abrasive of the large-flow circulating sand mill is used to refine the powder particles to improve the activity of the powder, reduce the activation energy of the reaction and effectively reduce the sintering temperature. The particle size distribution of the prepared powder is suitable for the requirements of the LTCF casting process (ordinary abrasive) D ₅₀ : 3 μm ~ 10 μm, large particle size, wide distribution range, poor uniformity).

As a preferred technical solution: step D is carried out by adopting LTCF multi-layer lamination process.

The material is suitable for the LTCF multi-layer lamination process and meets the performance requirements for the manufacture of chip devices.

Compared with the prior art, the present invention has the advantages of: wide-temperature nickel-zinc LTCF material of the present invention, LTCF100 material permeability μ _i 100±20%, power consumption Pv≤100kW/m ³ (100KHz@30mT, 20 ℃), sintering temperature 850～910℃, change rate of magnetic permeability μ _i <20% (-55～+85℃), LTCF300 material: magnetic permeability μ _i 300±20%, power consumption Pv≤130kW/m ³ (100KHz@30mT, 20℃), sintering temperature 850～910℃, change rate of magnetic permeability μ _i <20% (-55～+85℃), LTCF500 material: magnetic permeability μ _i 500±20%, power consumption _Pv≤150kW /m ³ (100KHz@30mT, 20°C), sintering temperature 850～910°C, change rate of magnetic permeability μi＜20% (-55～+85°C); excellent after firing at 900°C Microstructure, the compensation point where the peak II appears has moved below -55°C, there is a relatively flat μ _i —T curve between the peaks I and II, and the temperature stability is good, meeting the wide temperature -55 ~ +85°C high, The use reliability and environmental adaptability requirements of the magnetic properties of high-power multilayer chip ferrite devices in low-temperature application environments (the change rate of inductance L is -30% to +200%).

Description of drawings

Fig. 1 is the μ _i -T curve diagram of wide temperature power type LTCF material of the present invention;

Fig. 2 is the μ _i -T curve diagram of conventional power type LTCF500 material.

Fig. 3 is the micro-magnetic transformer L-T curve diagram that wide temperature LTCF material of the present invention is made;

Figure 4 is the L-T curve of the micro-magnetic transformer made of conventional LTCF500 material.

detailed description

The present invention will be further described below in conjunction with accompanying drawing.

Example 1:

A wide-temperature nickel-zinc LTCF100 material for high-power multilayer chip ferrite devices, the main components of which are expressed in molar percentages, as shown in Table 1:

Table 1 The main components of wide temperature LTCF100 materials (in mole percent)

NiO ZnO CuO _{Fe2O3 _} group 1 32 9 8 51 group 2 27 10 9 54 group 3 25 9 8 58

Group 1, Group 2 and Group 3 also include 0.3%, 0.5%, and 0.7% of the total weight of the above-mentioned main components of V ₂ O ₅ , respectively,

The preparation method is as follows:

A. Dry mixing: take the main components according to the proportion, use a high-frequency vibrating mixing system to crush and mix evenly to obtain a mixture, and the mixing time is 30 minutes;

B. Pre-sintering: pre-sintering the mixture obtained in step A in a sintering kiln, the pre-sintering temperature is 850 ° C, to obtain a pre-sintered material;

C. Wet grinding: add V ₂ O ₅ in the stated proportion to the pre-sintered material obtained in step B, and carry out wet grinding in a large-flow circulating sand mill to control the particle size distribution of the powder D ₅₀ < 2.0 μm , to obtain ultra-fine ferrite particles;

D. Secondary sintering: The ultra-fine ferrite particles obtained in step C are subjected to secondary sintering at a sintering temperature of 910° C. to obtain a finished product.

Example 2:

A wide-temperature nickel-zinc LTCF300 material for high-power multilayer chip ferrite devices, the main components of which are expressed in molar percentages, as shown in Table 2:

Table 2 The main components of the wide temperature LTCF300 material (in mole percent)

NiO ZnO CuO _{Fe2O3 _} group 4 19 twenty two 8 51 Group 5 20 18 10 52 Group 6 18 16 8 58

Group 4, Group 5, and Group 6 also include 0.3%, 0.4%, and 0.7% of the total weight of the above-mentioned main components of V ₂ O ₅ , respectively,

The preparation method is as follows:

A. Dry mixing: take the main components according to the proportion, use a high-frequency vibrating mixing system to crush and mix evenly to obtain a mixture, and the mixing time is 50 minutes;

B. Pre-sintering: pre-sintering the mixed material obtained in step A in a sintering kiln, the pre-sintering temperature is 820 ° C, to obtain a pre-sintered material;

C. Wet grinding: add V ₂ O ₅ in the stated proportion to the pre-sintered material obtained in step B, and carry out wet grinding in a large-flow circulating sand mill to control the particle size distribution of the powder D ₅₀ < 2.0 μm , to obtain ultra-fine ferrite particles;

D. Secondary sintering: the ultra-fine ferrite particles obtained in step C are subjected to secondary sintering at a sintering temperature of 900° C. to obtain a finished product.

Example 3:

A wide-temperature nickel-zinc LTCF500 material for high-power multilayer chip ferrite devices, the main components of which are expressed in molar percentages, as shown in Table 3:

Table 3 Main component examples of wide temperature LTCF500 materials (in mole percent)

NiO ZnO CuO _{Fe2O3 _} Group 7 12 29 8 51 Group 8 10 27 10 53 Group 9 8 26 8 58

Group 7, Group 8, and Group 9 also include 0.4%, 0.5%, and 0.7% of the total weight of the above-mentioned main components of V ₂ O ₅ , respectively,

The preparation method is as follows:

A. Dry mixing: take the main components according to the proportion, use a high-frequency vibrating mixing system to crush and mix evenly to obtain a mixture, and the mixing time is 60 minutes;

B. Pre-sintering: pre-sintering the mixed material obtained in step A in a sintering kiln, the pre-sintering temperature is 750 ° C, to obtain a pre-sintered material;

C. Wet grinding: add V ₂ O ₅ in the stated proportion to the pre-sintered material obtained in step B, and carry out wet grinding in a large-flow circulating sand mill to control the particle size distribution of the powder D ₅₀ < 2.0 μm , to obtain ultra-fine ferrite particles;

D. Secondary sintering: the ultra-fine ferrite particles obtained in step C are subjected to secondary sintering at a sintering temperature of 900° C. to obtain a finished product.

Example 4

Material Performance Testing

Adopt the product that the group 2 of embodiment 1, the group 5 of embodiment 2 and the group 8 of embodiment 3 gained respectively, measure μ _i -T curve (test condition is 100mV, 10KHz) and micro-magnetic transformer L-T curve ( The test conditions are 500mV, 100KHz, transformer model 10×10×3(mm)), and the results are shown in Figure 1 and Figure 3.

Comparative example: The conventional power type nickel-zinc LTCF500 material is used, and its main components are calculated by mole percentage, as shown in Table 4:

Table 4 The main components of conventional LTCF500 materials (in mole percent)

NiO ZnO CuO Co ₂ O _{3 Fe2O3 _} Group 10 12 33 10.78 0.22 44 Group 11 11 29 11.82 0.18 48 Group 12 13 27 10.84 0.16 49

Group 10, Group 11, and Group 12 also include 0.4%, 0.5%, and 0.7% of the total weight of the above-mentioned main components of V ₂ O ₅ , respectively,

The preparation method is as follows:

A. Dry mixing: take the main components according to the proportion, use a high-frequency vibrating mixing system to crush and mix evenly to obtain a mixture, and the mixing time is 60 minutes;

B. Pre-sintering: pre-sintering the mixed material obtained in step A in a sintering kiln, the pre-sintering temperature is 780 ° C, to obtain a pre-sintered material;

C. Wet grinding: add V ₂ O ₅ in the stated proportion to the pre-sintered material obtained in step B, and carry out wet grinding in a large-flow circulating sand mill to control the particle size distribution of the powder D ₅₀ < 2.0 μm , to obtain ultra-fine ferrite particles;

D. Secondary sintering: the ultra-fine ferrite particles obtained in step C are subjected to secondary sintering at a sintering temperature of 900° C. to obtain a finished product.

Adopt the product that comparative example group 11 gains, carry out test material μ _i -T curve (test condition is 100mV, 10KHz) and micromagnetic transformer L-T curve (test condition is 500mV, 100KHz, transformer model 10 under the above-mentioned identical conditions) ×10×3(mm)), the results are shown in Figure 2 and Figure 4.

It can be seen from Figure 1-4 that:

1. μ _i —T curve:

The conventional power type nickel-zinc LTCF500 material is made of NiCuZn deficient iron (Fe ₂ O ₃ content<50mol%) plus Co formula. The temperature position of the peak compensation point of item II is about -20°C, and the μ _i —T changes below this temperature Very large; the μ _i —T curve has a large valley between the peaks I and II at -20°C to +85°C, and the temperature stability is poor;

However, for the material of the present invention, the temperature position of the peak compensation point of item II has been moved below -55°C, the μ _i -T curve has a relatively flat area between -55°C and +85°C, and the temperature stability of the magnetic permeability and environmental adaptability are good.

2. Micro-magnetic transformer L-T curve:

The change law of L-T curve of the micro-magnetic transformer made of conventional materials between -55°C and +85°C is similar to that of the material μ _i -T curve, and the temperature stability and environmental adaptability of the inductance L are poor, especially Leakage inductance loss is greater in low temperature environments below -20°C;

However, the change law of the L-T curve of the micro-magnetic transformer made of the material of the present invention is similar to that of the material μ _i -T curve between -55°C and +85°C, and the temperature stability and environmental adaptability of the inductance L are good. , especially in low temperature environments between -20°C and -55°C, the loss of leakage inductance is very small.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (10)

1. a high-power multilayer sheet type ferrite device wide temperature nickel zinc LTCF material, it is characterised in that its main constituent is the following component with molar percent:

NiO 8mol%～35mol%

ZnO 9mol%～35mol%

CuO 8mol%～12mol%

Fe₂O₃ 51mol%～58mol%.

High-power multilayer sheet type ferrite device the most according to claim 1 wide temperature nickel zinc LTCF material, it is characterised in that also include the auxiliary element V of mass percent₂O₅ 0.3wt%～0.7wt%.

High-power multilayer sheet type ferrite device the most according to claim 1 wide temperature nickel zinc LTCF material, it is characterised in that: described LTCF material is LTCF100, LTCF300 or LTCF500.

High-power multilayer sheet type ferrite device the most according to claim 3 wide temperature nickel zinc LTCF material, it is characterised in that the main constituent of described LTCF100 material is the following component with molar percent:

NiO 25mol%～32mol%

ZnO 9mol%～14mol%

CuO 8mol%～12mol%

Fe₂O₃ 51mol%～58mol%.

High-power multilayer sheet type ferrite device the most according to claim 3 wide temperature nickel zinc LTCF material, it is characterised in that the main constituent of described LTCF300 material is the following component with molar percent:

NiO 18mol%～23mol%

ZnO 16mol%～22mol%

CuO 8mol%～12mol%

Fe₂O₃ 51mol%～58mol%.

High-power multilayer sheet type ferrite device the most according to claim 3 wide temperature nickel zinc LTCF material, it is characterised in that the main constituent of described LTCF500 material is the following component with molar percent:

NiO 8mol%～12mol%

ZnO 26mol%～33mol%

CuO 8mol%～12mol%

Fe₂O₃ 51mol%～58mol%.

7. the preparation method of the high-power multilayer sheet type ferrite device wide temperature nickel zinc LTCF material described in claim 2, it is characterised in that comprise the following steps:

A. dry method batch mixing: proportionally take described main constituent, broken rear mix homogeneously, obtain compound, mixing time is 30～60min；

B. presintering: the compound of step A gained is carried out presintering, and pre-sintering temperature is 750～850 DEG C, obtains presintering material；

C. wet method abrasive material: by the presintering material of step B gained, add the V of described ratio₂O₅, carry out wet method abrasive material, control powder particles particle size distributionD ₅₀ ＜ 2.5 μm, obtains hyperfine ferrite particle；

D. double sintering: by the hyperfine ferrite particle of step C gained, carrying out double sintering, sintering temperature is 850～910 DEG C, obtains finished product.

Method the most according to claim 7, it is characterised in that: step A is to use high frequency vibrating mixing system to carry out batch mixing, and step B is to carry out in sintering kiln.

Method the most according to claim 7, it is characterised in that: step C is to carry out in big flow recirculation system sand grinding machine.

Method the most according to claim 7, it is characterised in that: step D is to use LTCF multi-layer stacks technique.