阅读说明：本技术 磁粉芯用复合粉末及其磁粉芯制备方法 (Composite powder for magnetic powder core and preparation method of magnetic powder core ) 是由 柳萌 于 2021-08-25 设计创作，主要内容包括：一种磁粉芯用复合粉末,包括混合均匀的质量份为50-100份的粉末X和1-10份的粉末Y；其中,粉末X为铁基纳米晶粉,粉末Y为稀土基纳米粉。制备方法为将粘合剂和复合粉末,投入球磨机中,抽真空,充入液氮,球磨混合后；置于氮气氛中熔融、模压、冷却处理后,制得磁粉芯。通过在FeNbB磁铁中掺杂Nd、Si、Tb、Dy,制备成具备永磁特性的磁粉芯,通过Tb、Dy提高磁体的矫顽力。通过低温冷脆酚醛树脂,经球磨细化粒径与纳米级的复合粉末均匀混合,使熔融后的复合粉末均匀分散且被均匀的融合再模压成磁粉芯,保证了各组分的均匀分散性,均衡颗粒间的间隙,强化其稳定性、提高磁导、降低磁损耗,有效提升了磁粉芯的各项性能。(A composite powder for magnetic powder core comprises 50-100 parts of powder X and 1-10 parts of powder Y which are uniformly mixed; wherein, the powder X is iron-based nanocrystalline powder, and the powder Y is rare earth-based nanocrystalline powder. The preparation method comprises putting the adhesive and the composite powder into a ball mill, vacuumizing, filling liquid nitrogen, and ball-milling and mixing; and melting in nitrogen atmosphere, molding, and cooling to obtain the magnetic powder core. Nd, Si, Tb and Dy are doped into a FeNbB magnet to prepare a magnetic powder core with permanent magnetic properties, and the coercive force of the magnet is improved by the Tb and Dy. The low-temperature cold-brittle phenolic resin is subjected to ball milling to refine the particle size and is uniformly mixed with the nanoscale composite powder, so that the fused composite powder is uniformly dispersed and uniformly fused and then is molded into the magnetic powder core, the uniform dispersibility of each component is ensured, the gaps among particles are balanced, the stability of the magnetic powder core is enhanced, the magnetic conductance is improved, the magnetic loss is reduced, and various performances of the magnetic powder core are effectively improved.)

1. The composite powder for the magnetic powder core is characterized by comprising powder X and powder Y which are uniformly mixed;

the powder X is iron-based nanocrystalline powder containing Fe and at least 2 of Nb, Si and B,

the powder Y is rare earth-based nano powder containing Nd, Fe or B;

the composite powder has a composition of Fe_aNd_bNb_cB_dSi_eTb_fDy_g；

Wherein a =60-70, b =10-15, c =6-10, d =4-8, e =4-8, f =0-3, g = 0-3.

2. The composite powder for a magnetic powder core according to claim 1, wherein the combination of the composite powder is Fe₆₀Nd₁₅Nb₁₀B₅Si₄Tb₃Dy₃(ii) a Or Fe₇₀Nd₁₀Nb₉B₅Si₆(ii) a Or Fe₆₇Nd₁₂Nb₉B₄Si₄Tb₂Dy₂。

3. The composite powder for a magnetic powder core according to claim 1, wherein the powder X is 50 to 100 parts by mass and the powder Y is 1 to 10 parts by mass.

4. The preparation method of the magnetic powder core is characterized by comprising the following steps:

s1, mixing the following raw materials: putting a binder and the composite powder for magnetic powder cores according to any one of claims 1 to 3 into a ball mill, vacuumizing, filling liquid nitrogen, and ball-milling and mixing;

and S2, melting the ball-milled compound in a nitrogen atmosphere, molding, and cooling to obtain the magnetic powder core.

5. The method of manufacturing a magnetic powder core according to claim 4, wherein the diameter of the grinding ball in the step S1 is 0.5-20 mm; the mass ratio of the raw materials to the grinding balls is 1 (10-1000); the ball milling time is 0.5-120 h.

6. The method of claim 4, wherein the binder comprises epoxy resin and/or phenolic resin, and the mass of the binder is 0.5-3.5% of the mass of the magnetic powder core.

7. The method of claim 4, wherein the liquid nitrogen temperature is- (160-180) deg.C, the molding temperature is between 150-175 deg.C, and the molding pressure is 1500-2000 MPa.

Technical Field

The invention relates to composite powder for a magnetic powder core, in particular to composite powder for the magnetic powder core and a preparation method of the magnetic powder core.

Background

The magnetic powder core is a composite material which is formed by insulating and coating ferromagnetic powder and pressing the ferromagnetic powder through powder metallurgy. Because the ferromagnetic particles are very small (0.5-5 microns used at high frequency) and are separated by the non-magnetic electric insulating film substance, on one hand, eddy current can be isolated, and the material is suitable for higher frequency; on the other hand, due to the gap effect among the particles, the material has low magnetic permeability and constant magnetic conductivity; and because the particle size is small, the skin phenomenon basically does not occur, and the magnetic conductivity is more stable along with the change of the frequency. The inductor is mainly used for high-frequency inductors.

The magnetoelectric performance of the magnetic powder core mainly depends on the magnetic permeability of the powder particle materials, the size and the shape of the powder particles, the filling coefficients of the powder particles, the content of insulating media, the forming pressure, the heat treatment process and the like. The magnetic powder core is composed of three kinds of core, iron powder core, permalloy powder core and iron-silicon-aluminum powder core.

The nanocrystalline soft magnetic powder core is a nanocomposite magnetic core which is formed by compounding a nanocrystalline metal material (iron base) serving as a matrix material with other nano powder and strictly according to certain size and structure requirements. The product has the characteristics of high saturation magnetic induction, low iron loss, high initial permeability and low coercive force, can replace traditional soft magnetic material iron cores such as silicon steel, permalloy and ferrite, and realizes the functions of high-frequency signal conversion, control, protection, filtering, interference resistance, voltage stabilization, multi-path output, voltage regulation and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide composite powder for a magnetic powder core and a preparation method of the magnetic powder core.

In order to achieve the above object, the present invention adopts the following technical solutions:

the composite powder for the magnetic powder core comprises 50-100 parts by mass of powder X and 1-10 parts by mass of powder Y which are uniformly mixed;

wherein, the powder X is iron-based nanocrystalline powder, and the powder Y is rare earth-based nanocrystalline powder.

The iron-based nanocrystalline powder contains Fe and at least 2 of Nb, Si and B.

The rare earth-based nanopowder contains Nd, Fe, or B.

Furthermore, the rare earth nano powder also contains Tb and Dy, and the mass parts of the Tb and Dy are 1-3 parts and 1-3 parts respectively.

The composite powder is Fe_aNd_bNb_cB_dSi_eTb_fDy_g；

Wherein a =60-70, b =10-15, c =6-10, d =4-8, e =4-8, f =0-3, g = 0-3.

Further, the combination of the composite powders is Fe₆₀Nd₁₅Nb₁₀B₅Si₄Tb₃Dy₃(ii) a Or Fe₇₀Nd₁₀Nb₉B₅Si₆(ii) a Or Fe₆₇Nd₁₂Nb₉B₄Si₄Tb₂Dy₂。

The preparation method of the magnetic powder core comprises the following steps:

s1, mixing the following raw materials: putting the composite powder for the adhesive and the magnetic powder core into a ball mill, vacuumizing, filling liquid nitrogen, and ball-milling and mixing;

and S2, melting the ball-milled compound in a nitrogen atmosphere, molding, and cooling to obtain the magnetic powder core.

The diameter of the grinding ball in the step S1 is 0.5-20 mm; the mass ratio of the raw materials to the grinding balls is 1 (10-1000), preferably 1:50-1: 300; the ball milling time is 0.5-120h, preferably 1-50 h.

The adhesive comprises epoxy resin and/or phenolic resin, and the mass of the adhesive accounts for 0.5-3.5% of the mass of the magnetic powder core.

The temperature of the liquid nitrogen is between 160 ℃ and 180 ℃, the mould pressing temperature is between 150 ℃ and 175 ℃, and the mould pressing pressure is 1500MPa and 2000 MPa.

The invention has the advantages that:

the composite powder for the magnetic powder core is prepared by doping a certain amount of Nd, Si, Tb and Dy in conventional Fe, Nb and B magnets, forming the magnetic powder core with a certain permanent magnetic property in a preparation mode of soft magnet, and improving the coercive force of the magnet through Tb and Dy. According to the invention, the phenolic resin is subjected to low-temperature cold embrittlement, and then ball milling to refine the particle size, and the phenolic resin is uniformly mixed with the nanoscale composite powder, so that the fused composite powder is uniformly dispersed and uniformly fused, and then is molded into the magnetic powder core, thus ensuring uniform dispersion of each component in the magnetic powder core, balancing gaps among particles, strengthening the stability, improving magnetic conductance and reducing magnetic loss, and increasing the relative density after molding by a more uniform mixing mode, thereby improving thermal stability; the preparation method is simple, low in cost and good in effect, effectively improves various performances of the magnetic powder core, and has strong practicability and wide applicability.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The composite powder for the magnetic powder core is formed by uniformly mixing powder X and powder Y; wherein the powder X is iron-based nanocrystalline powder, and the mass part of the powder X is 50-100 parts; the powder Y is rare earth-based nano powder and accounts for 1-10 parts by mass.

The iron-based nanocrystalline powder contains Fe and at least 2 of Nb, Si and B. The rare earth-based nano powder contains Nd, Fe, Tb, Nd, Fe, Dy, Nd, Fe, Tb and Dy, or Nd, Fe, B, Nd, Fe, Tb and B, or Nd, Fe, Dy and B, or Nd, Fe, Tb, Dy and B;

preferably, the composite powder has a combination of ingredients of Fe_aNd_bNb_cB_dSi_eTb_fDy_gWherein a =60-70, b =10-15, c =6-10, d =4-8, e =4-8, f =0-3, g = 0-3.

More preferably, the composite powder has a combination of components of Fe₆₀Nd₁₅Nb₁₀B₅Si₄Tb₃Dy₃(ii) a Or Fe₇₀Nd₁₀Nb₉B₅Si₆(ii) a Or Fe₆₇Nd₁₂Nb₉B₄Si₄Tb₂Dy₂。

The preparation method of the magnetic powder core comprises the following steps:

s0, selecting the following raw materials:

adhesive: a phenolic resin;

the target component of the composite powder is Fe₆₇Nd₁₂Nb₉B₄Si₄Tb₂Dy₂. Selecting the atomic component as Fe₇₀Nb₁₀B_{4。 5}Si_4.590 parts of iron-based nanocrystalline powder, wherein the selected atomic component is Nd₁₂Fe₄Tb₂Dy₂Is 10 portions of rare earth base nanometer powder.

S1, mixing the following raw materials: putting 35g of phenolic resin and 965g of composite powder into a ball mill, wherein the diameter of a grinding ball is 1mm, the mass of the grinding ball is 50kg, vacuumizing, filling liquid nitrogen with the temperature of minus 160 ℃, and ball-milling for 48 hours for mixing;

s2, introducing the ball-milled compound into a mold, heating to 250 ℃ for melting in nitrogen atmosphere, reducing the temperature to 150 ℃ at the speed of 10 ℃/10min, carrying out compression molding at the pressure of 1500MPa, keeping the temperature at the pressure of 300MPa and the temperature of 80-90 ℃ for 1h, and cooling to room temperature at the speed of 5 ℃/min to obtain the magnetic powder core.

The performance indexes are as follows:

1) using the frequency range f: 0.1MHz-300 MHz;

2) saturation magnetic flux density Bs: 1.22T;

3) temperature stability: 92 PPM/DEG C;

4) density ρ: 5.88g/cm³；

5) permeability/(H/m) (50kHz, 0.05T): 143;

6) magnetic core loss/(W/cm)³)(50kHz，0.05mT)：47。

During actual preparation, the proper component proportion of the composite powder can be selected according to the use requirement so as to obtain the required magnetic powder core with corresponding performance.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.