CN104078230B - A kind of high-silicon electrical steel iron core of intergranular insulation and preparation method thereof - Google Patents

Abstract

The invention relates to an intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. Its technical scheme is: according to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (6~10): (0.04~0.1): (0.2~0.5) the iron-silicon alloy powder, Add absolute ethanol, silane coupling agent and distilled water into the reaction vessel in turn, stir; then add ethyl orthosilicate or methyl orthosilicate to it, add ammonia water, continue to stir; wash, filter, dry; then in 600 Heat preservation at ~800°C for 1~3h, cool with the furnace, and press into shape; finally put it in a sintering furnace, sinter at 950~1350°C for 1~10h, and cool with the furnace to obtain high-silicon electrical steel with intergranular insulation core. The invention has the characteristics of simple process, short cycle time, high material utilization rate and low cost, and the prepared intercrystalline high-silicon electrical steel core has low iron loss, good stability and long service life.

Description

A kind of high-silicon electrical steel core with intergranular insulation and its preparation method

technical field

The invention belongs to the technical field of high-silicon electrical steel cores. Specifically relates to an intercrystalline insulating high-silicon electrical steel core and a preparation method thereof.

Background technique

In recent years, with the advancement of energy saving and emission reduction policies and the popularization and application of high-efficiency motors, the demand for high-grade non-oriented electrical steel in the field of small and medium-sized motors and micro motors will increase significantly in the future. In addition, with the popularization of the frequency conversion control mode of mainstream motors and the development of high-speed rotating motors, the requirements for high frequency, high magnetic induction and low iron loss have been put forward for non-oriented electrical steel. High-silicon electrical steel has excellent soft magnetic properties such as low iron loss, high magnetic induction, high magnetic permeability and low hysteresis stretching. The key to stability and greenness.

As we all know, since the eddy current loss of the iron core is positively related to the square of the thickness of the electrical steel sheet, the thickness of the electrical steel sheet should be reduced as much as possible, and its thickness is usually controlled below 1mm by rolling to reduce the eddy current loss. However, for high-silicon electrical steel, especially when the silicon content exceeds 4.5wt%, ordered phases of B ₂ and DO ₃ tend to appear in the high-silicon electrical steel, resulting in a sharp decline in plasticity and toughness, and the elongation is almost zero. , Forming and punching are extremely difficult, and the production and application are severely restricted. Therefore, it is difficult to control the thickness of high-silicon electrical steel within 1mm by conventional rolling methods.

Aiming at the sharp decline in ductility and toughness of high-silicon electrical steel and the difficulty in rolling forming, domestic and foreign scholars have carried out a lot of research on the reasons for the increase in brittleness of high-silicon electrical steel, how to enhance its ductility and how to avoid the brittleness of electrical steel. Research has brought forward many new technologies and methods, which have effectively promoted the development of high-silicon electrical steel. The purpose of technological innovation is to improve its plasticity, toughness and machinability through structural control, or completely avoid the traditional rolling process, and use a new method to prepare high-silicon electrical steel sheets. Methods such as spray forming and melt rapid quenching die casting (solidification) based on rapid solidification (cooling) technology can effectively inhibit or reduce the formation of ordered phases to improve the machinability of high-silicon electrical steel. It is also possible to add trace alloy elements and optimize the existing rolling technology, such as "a chromium-containing high-silicon steel strip and its preparation method" (CN103276174A) patent technology and "a high-silicon steel strip and its preparation method" (CN101935800B ) patented technology, using the most conventional hot rolling-cold rolling, or forging-hot rolling-warm rolling-cold rolling process to gradually improve the ductility of high-silicon electrical steel, and can also successfully obtain ultra-thin high-silicon electrical steel with excellent performance sheet. Another research idea is to avoid the existing rolling technology and develop related technologies based on deposition-diffusion methods, such as chemical vapor deposition, plasma chemical vapor deposition, thermal dip siliconization, embedded siliconization, magnetron sputtering Technology such as radiation, molten salt electrodeposition, electron beam physical vapor deposition, laser cladding, electrophoretic deposition, etc., as well as the patented technology of "Preparation of high-silicon silicon steel thin strip by hot-dip silicon plating method and continuous preparation device of silicon steel strip" (CN103320737A) And the patented technology of "Industrial production system for high-silicon steel strips produced by magnetron sputtering continuous double-sided co-deposition process" (CN101319306A), both of which can obtain high-silicon electrical steel sheets with excellent performance.

Although domestic and foreign researchers have carried out extensive and in-depth basic research work on various issues related to high-silicon electrical steel, the above-mentioned existing technologies are either due to high cost, or due to environmental constraints, or due to insufficient maturity of the process, or Its further application is restricted due to the low utilization rate of materials.

Contents of the invention

The present invention aims to overcome the deficiencies of the prior art, and the purpose is to provide a high-silicon electrical steel core with intergranular insulation with low iron loss, good stability, long service life, high material utilization rate and low production cost and its preparation method .

In order to achieve the above object, the specific steps of the preparation method of the present invention are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (6~10): (0.04~0.1): (0.2~0.5), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 40-70° C. for 1-3 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under stirring conditions at 40-70°C, firstly add ethyl orthosilicate or methyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, at 40-70°C Continue to stir for 8-24 hours under the condition; wash with distilled water for 2-3 times, wash with absolute ethanol for 5-8 times, filter, and vacuum-dry to obtain core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: ethyl orthosilicate is 1: (0.1~2), the mass ratio of iron-silicon alloy powder: methyl orthosilicate is 1: (0.1~2); iron-silicon alloy powder : The mass ratio of ammonia water is 1: (0.02~0.4).

The third step, annealing heat treatment

The core-shell heterostructure composite powder is put into an annealing furnace, kept at 600-800° C. for 1-3 hours, and cooled to room temperature with the furnace to obtain annealed heat-treated core-shell heterostructure composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is compacted to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

The high-silicon electrical steel powder compact is put into a sintering furnace, sintered at 950° C. to 1350° C. for 1-10 hours, and cooled to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core.

The Si content of the iron-silicon alloy powder is 4.0-7.5wt%.

The annealing furnace is a vacuum-protected annealing furnace or an inert gas-protected annealing furnace.

The sintering furnace is a vacuum-protected sintering furnace or an inert gas-protected sintering furnace.

The pressure of the compression molding is 100Mpa~600Mpa.

Owing to adopting above-mentioned technical scheme, the present invention has following advantage:

1) The preparation method of the high-silicon electrical steel core with intercrystalline insulation disclosed by the present invention avoids the bottleneck of the existing high-silicon electrical steel that is difficult to roll, and can obtain the high-silicon electrical steel core by one-step sintering without rolling, Compared with the prior art, the process is simple, the cycle is short and the cost is low.

2) The present invention adopts the surface coating method to coat the silicon dioxide insulating layer on the surface of the iron-silicon alloy, which realizes the insulation between the iron-silicon alloy particles, avoids the use of the existing high-silicon electrical steel flake insulating coating, and improves the high The stability of the silicon electrical steel core prolongs the service life.

3) The eddy current of the high-silicon electrical steel core with intergranular insulation prepared by the present invention is limited in the iron-silicon alloy in the insulation coating area, and compared with the existing high-silicon electrical steel core, the eddy current loss is smaller and the iron loss is lower .

The high-silicon electrical steel core with intergranular insulation prepared in this specific embodiment is tested: the saturation magnetic induction is 158~186emu/g; the resistivity is 1.9×10 ^-2 Ω*m~insulation; the iron loss P _5/50 is 0.25~0.50W/kg, P _5/400 is 5.85~10.32W/kg, P _5/1000 is 20.93~36.92W/kg.

4) The preparation method of the high-silicon electrical steel core proposed by the present invention can directly prepare ring-shaped, E-shaped, round-shaped, fan-shaped and other special-shaped iron cores through the design of the mold, without punching process, high material utilization rate and low cost .

Therefore, the invention has the characteristics of simple process, short cycle time, high material utilization rate and low cost; the prepared intercrystalline high-silicon electrical steel core has low iron loss, good stability and long service life.

Description of drawings

Fig. 1 is the cross-sectional SEM figure of a kind of intergranular insulation high-silicon electrical steel core prepared by the present invention;

Fig. 2 is the iron loss spectrogram of the high-silicon electrical steel core of intergranular insulation shown in Fig. 1 under different frequencies;

Fig. 3 is a physical diagram of the high-silicon electrical steel core with intergranular insulation shown in Fig. 1 .

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, which are not intended to limit the protection scope thereof.

The Si content of the iron-silicon alloy powder described in this specific embodiment is 4.0-7.5wt%, which will not be repeated in the examples.

Example 1

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (6~7): (0.04~0.05): (0.2~0.25), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 40-45°C for 1.5-2 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 40~45°C, firstly add ethyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue to stir at 40~45°C for 8~ 10 hours; wash with distilled water 2-3 times, wash with absolute ethanol 5-6 times, filter, and vacuum-dry to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: ethyl orthosilicate is 1: (0.1~0.4); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.02~0.05).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into a vacuum-protected annealing furnace, keep it warm at 600-650°C for 1.5-2 hours, and cool down to room temperature with the furnace to obtain annealed heat-treated core-shell heterostructure composite powder .

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 100-200Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into a vacuum-protected sintering furnace, sinter at 950-1000° C. for 2-4 hours, and cool down to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core.

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 184~186emu/g; the resistivity is 2.8×10 ^-2 ~3.0×10 ^-2 Ω*m; the iron loss is P _{5 /50} is 0.42~0.43W/kg, P _5/400 is 8.93~9.01W/kg, P _5/1000 is 31.95~32.24W/kg.

Example 2

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (7~8): (0.05~0.06): (0.25~0.3), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 45-50°C for 2.5-3 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under stirring conditions at 45-50°C, first add methyl orthosilicate to the mixed solution containing surface-modified iron-silicon alloy powder, then add ammonia water, and continue stirring at 45-50°C for 10~ 12 hours; wash with distilled water for 2 to 3 times, wash with absolute ethanol for 6 to 7 times, filter, and dry in vacuum to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: methyl orthosilicate is 1: (0.4~0.6); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.05~0.1).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into a vacuum-protected annealing furnace, keep it warm at 650-700°C for 2-2.5 hours, and cool down to room temperature with the furnace to obtain an annealed heat-treated core-shell heterostructure composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 200-300Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into a vacuum-protected sintering furnace, sinter at 1000-1050° C. for 4-6 hours, and cool down to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core.

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 180~182emu/g; the resistivity is 1.4×10 ^-2 ~1.6×10 ^-2 Ω*m; the iron loss is P _{5 /50} is 0.36~0.37W/kg, P _5/400 is 7.66~7.74W/kg, P _5/1000 is 27.41~27.69W/kg.

Example 3

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (8~9): (0.06~0.07): (0.3~0.35), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 50-55° C. for 1-1.5 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 50~55°C, firstly add ethyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue to stir at 50~55°C for 12~ 14 hours; wash with distilled water 2-3 times, wash with absolute ethanol 7-8 times, filter, and vacuum-dry to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: ethyl orthosilicate is 1: (0.6~1); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.1~0.15).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into a vacuum-protected annealing furnace, keep it warm at 700-750°C for 2.5-3 hours, and cool down to room temperature with the furnace to obtain annealed heat-treated core-shell heterostructure composite powder .

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 300-400Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into an inert gas-protected sintering furnace, sinter at 1050-1100°C for 6-8 hours, and cool to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core .

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 176~178emu/g; the resistivity is 8.0×10 ^-1 ~8.2×10 ^-1 Ω*m; the iron loss is P _{5 /50} is 0.33~0.34W/kg, P _5/400 is 7.14~7.22W/kg, P _5/1000 is 25.55~25.83W/kg.

Example 4

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (9~10): (0.07~0.08): (0.35~0.40), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 55-60°C for 2-2.5 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 55~60°C, first add methyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue stirring at 55~60°C for 14~ 16 hours; wash with distilled water 2-3 times, wash with absolute ethanol 5-6 times, filter, and vacuum-dry to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: methyl orthosilicate is 1: (1~1.2); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.15~0.2).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into a vacuum-protected annealing furnace, keep it warm at 750-800°C for 1-1.5h, and cool down to room temperature with the furnace to obtain an annealed heat-treated core-shell heterostructure composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 400-500Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into an inert gas-protected sintering furnace, sinter at 1100-1150°C for 8-10 hours, and cool down to room temperature with the furnace to obtain an intergranular insulating high-silicon electrical steel core .

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 175-177emu/g; the resistivity is insulating; the iron loss P _5/50 is 0.29-0.30W/kg, and the P _{5/ 400} is 6.11~6.19W/kg, P _5/1000 is 21.86~22.14W/kg.

Example 5

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (6~6.5): (0.08~0.09): (0.4~0.45), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 60-65° C. for 1.5-2 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 60~65°C, first add methyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue stirring at 60~65°C for 16~ 18 hours; wash with distilled water for 2-3 times, wash with absolute ethanol for 7-8 times, filter, and vacuum-dry to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: methyl orthosilicate is 1: (1.2~1.4); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.2~0.25).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into an annealing furnace protected by inert gas, keep it warm at 600-700°C for 1-2h, and cool down to room temperature with the furnace to obtain an annealed heat-treated core-shell heterostructure composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 500-600Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into a vacuum-protected sintering furnace, sinter at 1150-1200° C. for 1-3 hours, and cool down to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core.

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 168~170emu/g; the resistivity is insulating; the iron loss P _5/50 is 0.28~0.30W/kg, P _{5/ 400} is 6.04~6.12W/kg, P _5/1000 is 21.61~21.90W/kg.

Example 6

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (6.5~8): (0.09~0.1): (0.45~0.5), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 65-70° C. for 2.5-3 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 65~70°C, first add methyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue stirring at 65~70°C for 18~ 20 hours; wash with distilled water for 2-3 times, wash with absolute ethanol for 7-8 times, filter, and vacuum-dry to obtain core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: methyl orthosilicate is 1: (1.4~1.6); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.25~0.3).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into an annealing furnace protected by inert gas, keep it warm at 700-800°C for 2-3 hours, and cool down to room temperature with the furnace to obtain an annealed heat-treated core-shell heterostructure composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 350-400Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into an inert gas-protected sintering furnace, sinter at 1200-1250°C for 3-5 hours, and cool down to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core .

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 165~167emu/g; the resistivity is insulating; the iron loss P _5/50 is 0.27~0.28W/kg, P _{5/ 400} is 5.85~5.93W/kg, P _5/1000 is 20.93~21.22W/kg.

Example 7

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (8~8.5): (0.04~0.07): (0.25~0.35), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 40-55° C. for 1-2 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 40~55°C, firstly add ethyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue stirring for 20~ 22 hours; wash with distilled water 2-3 times, wash with absolute ethanol 6-7 times, filter, and vacuum-dry to obtain core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: ethyl orthosilicate is 1: (1.6~1.8); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.3~0.35).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into an annealing furnace protected by inert gas, keep it warm at 730-780°C for 1-1.5h, and cool down to room temperature with the furnace to obtain an annealed heat-treated core-shell heterostructure Composite powder.

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 400-450Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into a vacuum-protected sintering furnace, sinter at 1250-1300° C. for 5-7 hours, and cool down to room temperature with the furnace to obtain an intercrystalline high-silicon electrical steel core.

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 170~172emu/g; the resistivity is 1.9×10 ^-2 ~2.1×10 ^-2 Ω*m; the iron loss is P _{5 /50} is 0.49~0.50W/kg, P _5/400 is 10.24~10.32W/kg, P _5/1000 is 36.64~36.92W/kg.

Example 8

An intercrystalline insulating high-silicon electrical steel core and a preparation method thereof. The concrete steps of described preparation method are:

The first step, surface modification of iron-silicon alloy powder

According to the mass ratio of iron-silicon alloy powder: absolute ethanol: silane coupling agent: distilled water is 1: (8.5~10): (0.07~0.1): (0.3~0.35), the iron-silicon alloy powder, absolute ethanol, The silane coupling agent and distilled water are sequentially added into the reaction vessel, and stirred at 55-70° C. for 2-3 hours to obtain a mixed solution containing surface-modified iron-silicon alloy powder.

The second step, preparation of core-shell heterostructure composite powder

Under the condition of stirring at 55~70°C, firstly add tetraethyl orthosilicate to the mixed solution containing the surface-modified iron-silicon alloy powder, then add ammonia water, and continue to stir at 55~70°C for 22~ 24 hours; wash with distilled water 2-3 times, wash with absolute ethanol 5-6 times, filter, and vacuum-dry to obtain a core-shell heterostructure composite powder.

Among them: the mass ratio of iron-silicon alloy powder: ethyl orthosilicate is 1: (1.8~2); the mass ratio of iron-silicon alloy powder: ammonia water is 1: (0.02~0.4).

The third step, annealing heat treatment

Put the core-shell heterostructure composite powder into a vacuum-protected annealing furnace, keep it warm at 780-800°C for 1.5-2 hours, and cool down to room temperature with the furnace to obtain annealed heat-treated core-shell heterostructure composite powder .

The fourth step, preparation of high-silicon electrical steel powder compact

The annealed core-shell heterogeneous structure composite powder is press-molded, and the pressure of the press-molding is 450-500Mpa to obtain a high-silicon electrical steel powder compact.

The fifth step, the preparation of high-silicon electrical steel core with intergranular insulation

Put the high-silicon electrical steel powder compact into an inert gas-protected sintering furnace, sinter at 1300-1350°C for 7-10 hours, and cool down to room temperature with the furnace to obtain an intergranular insulating high-silicon electrical steel core .

The high-silicon electrical steel core with intergranular insulation prepared in this example is tested: the saturation magnetic induction is 158~160emu/g; the resistivity is insulating; the iron loss P _5/50 is 0.25~0.27W/kg, P _{5/ 400} is 5.87~5.95W/kg, P _5/1000 is 21.00~21.29W/kg.

Compared with the prior art, this specific embodiment has the following positive effects:

1) The preparation method of the high-silicon electrical steel core with intergranular insulation disclosed in this specific embodiment avoids the bottleneck that the existing high-silicon electrical steel is difficult to roll, and the high-silicon electrical steel core can be obtained by one-step sintering without rolling Compared with the prior art, the process is simple, the cycle is short, and the cost is low.

2) This specific embodiment adopts the surface coating method to coat the silicon dioxide insulating layer on the surface of the iron-silicon alloy, which realizes the insulation between the iron-silicon alloy particles, avoids the use of the existing high-silicon electrical steel flake insulating coating, and improves The stability of the high-silicon electrical steel core is improved, and the service life is prolonged. Fig. 1 is a SEM image of a high-silicon electrical steel core with intergranular insulation prepared in Embodiment 4. It can be seen that the high-silicon electrical steel core with intergranular insulation The iron-silicon alloy powder in the steel core is evenly covered by _SiO2 , which realizes the insulation between the iron-silicon alloy particles.

3) The high-silicon electrical steel core with intergranular insulation prepared in this specific embodiment, its eddy current is limited in the iron-silicon alloy in the insulating coating area, and compared with the existing high-silicon electrical steel core, the eddy current loss is small, and the iron Figure 2 is the iron loss spectrum of the intergranular insulating high-silicon electrical steel core shown in Figure 1 at different frequencies. It can be seen that the iron loss P _5/50 is 0.25~0.27W/kg, and P _{5/ 400} is 5.87~5.95W/kg, P _5/1000 is 21.00~21.29W/kg.

The high-silicon electrical steel core with intergranular insulation prepared in this specific embodiment is tested: the saturation magnetic induction is 158~186emu/g; the resistivity is 1.9×10 ^-2 Ω*m~insulation; the iron loss P _5/50 is 0.25~0.50W/kg, P _5/400 is 5.85~10.32W/kg, P _5/1000 is 20.93~36.92W/kg.

4) The preparation method of the high-silicon electrical steel core proposed in this specific embodiment can directly prepare ring-shaped, E-shaped, round-shaped, fan-shaped and other special-shaped iron cores through the design of the mold, without punching process, and the material utilization rate is high. low cost. Fig. 3 is the actual object of the high-silicon electrical steel core with intergranular insulation shown in Fig. 1. It can be seen that the ring-shaped high-silicon electrical steel core with intergranular insulation is directly prepared through the design of the mold.

Therefore, this specific embodiment has the characteristics of simple process, short cycle time, high material utilization rate and low cost; the prepared intergranular insulating high-silicon electrical steel core has low iron loss, good stability and long service life.

Claims (6)

1. the preparation method of the high-silicon electrical steel iron core of an intergranular insulation, it is characterised in that the concrete steps of described preparation method It is:

The first step, ferro-silicium powder surface modifications

By ferro-silicium powder: dehydrated alcohol: silane coupler: the mass ratio of distilled water is 1:(6 ~ 10): (0.04 ~ 0.1): (0.2 ~ 0.5), is sequentially added into ferro-silicium powder, dehydrated alcohol, silane coupler and distilled water in reaction vessel, 40 ~ Stir 1 ~ 3h under the conditions of 70 DEG C, obtain the mixed solution of ferro-silicium powder containing surface modification；

Second step, the preparation of nucleocapsid heterojunction structure composite powder

Under 40 ~ 70 DEG C and stirring condition, first add in the mixed solution of the described ferro-silicium powder containing surface modification Tetraethyl orthosilicate or methyl silicate, add ammonia, continues stirring 8 ~ 24h under the conditions of 40 ~ 70 DEG C；With distilled water wash 2 ~ 3 times, with absolute ethanol washing 5 ~ 8 times, filter, vacuum drying, obtain nucleocapsid heterojunction structure composite powder；

Wherein: ferro-silicium powder: the mass ratio of tetraethyl orthosilicate is 1:(0.1 ~ 2), ferro-silicium powder: methyl silicate Mass ratio is 1:(0.1 ~ 2)；Ferro-silicium powder: the mass ratio of ammonia is 1:(0.02 ~ 0.4)；

3rd step, annealing heat treatment

Described nucleocapsid heterojunction structure composite powder is inserted in annealing furnace, under the conditions of 600 ~ 800 DEG C, is incubated 1 ~ 3h, cold with stove But to room temperature, it is thus achieved that the nucleocapsid heterojunction structure composite powder annealing heat treated；

4th step, the preparation of high-silicon electrical steel powder compact

By compressing for the described nucleocapsid heterojunction structure composite powder made annealing treatment, it is thus achieved that high-silicon electrical steel powder compact；

The preparation of the high-silicon electrical steel iron core of the 5th step, intergranular insulation

Described high-silicon electrical steel powder compact is inserted in sintering furnace, under the conditions of 950 ~ 1350 DEG C, sinters 1 ~ 10h, cold with stove But to room temperature, the high-silicon electrical steel iron core of intergranular insulation is obtained.

2. the preparation method of the high-silicon electrical steel iron core insulated according to intergranular described in claim 1, it is characterised in that described ferrum The Si content of silicon alloy powder is 4.0 ~ 7.5wt%.

3. according to the preparation method of high-silicon electrical steel iron core of the insulation of intergranular described in claim 1, it is characterised in that described in move back Stove is the annealing furnace of vacuum protection or for the annealing furnace of inert gas shielding.

4. the preparation method of the high-silicon electrical steel iron core insulated according to intergranular described in claim 1, it is characterised in that described burning Freezing of a furnace is the sintering furnace of vacuum protection or for the sintering furnace of inert gas shielding.

5. the preparation method of the high-silicon electrical steel iron core insulated according to intergranular described in claim 1, it is characterised in that described pressure The pressure making type is 100 ~ 600Mpa.

6. the high-silicon electrical steel iron core of an intergranular insulation, it is characterised in that the high-silicon electrical steel iron core of described intergranular insulation is root Exhausted according to the intergranular prepared by the preparation method of the high-silicon electrical steel iron core of the intergranular insulation according to any one of claim 1 ~ 5 The high-silicon electrical steel iron core of edge.