CN107900356A

CN107900356A - A kind of method that powder tape casting prepares high silicon steel band with High temperature diffusion sintering

Info

Publication number: CN107900356A
Application number: CN201711368369.8A
Authority: CN
Inventors: 罗丰华; 周海铭; 郭晓琼; 李益民; 贾吉祥
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2018-04-13

Abstract

A kind of method that powder tape casting and High temperature diffusion sintering prepare high silicon steel band, it for 50~70% HIGH-PURITY SILICON iron powder is raw material that the present invention, which uses water-atomized iron powder and Si contents, formation Fe 4.5~6.7%Si mixed powders.Solvent, dispersant, bonding agent and plasticizer are added in mixed powder again, finely dispersed stable slurry is made, then biscuit is made on casting machine.In 1060~1160 DEG C of progress vacuum or protection of reducing atmosphere sintering in biscuit, Fe powder particles are made to realize not exclusively sintering, and Si and Fe realizes partially-alloyed, the high silicon steel blank of porous, the incomplete alloying of formation.By multiple cold rolling, not exclusively sintering, finally sintered in 1250~1320 DEG C of vacuum or protection of reducing atmosphere, realize the homogeneous alloy of high silicon steel, 0.1~0.5mm of the acquisition containing 4.5~6.7%Si is thick, density >=7.38g/cm³High silicon steel band.

Description

A kind of method that powder tape casting prepares high silicon steel band with High temperature diffusion sintering

Technical field

Preparation and manufacture field the invention belongs to metal material, and in particular to the powder of the high silicon steel soft magnetism band of high-performance The method of tape casting and sintering densification.

Technical background

Remanent magnetism and coercive force all very littles of soft magnetic material, i.e. hysteresis curve is very narrow, it and fundamental magnetization curve are almost Overlap, be mainly used for the iron core of inductance coil, transformer, relay and motor.Fe-Si alloys maximum permeability is sent out with Si contents Changing, respectively Si mass percent it is (the same below) for 2% and 6.5% nearby there is the peak of two maximum permeabilities Value, respectively reaches 10000 and 25000.The maximum permeability of Fe-Si alloys does not have absolute predominance, such as slope in soft magnetic materials The maximum permeability of alloy can not reach 200000.But the Fe-Si lattens of Si ＜ 4.5% manufacture cost is low, therefore Silicon steel sheet is also known as electrical sheet or silicon steel thin slice, is a kind of very important magnetic material.

And Si>When 4.5%, below 540 DEG C of temperature B can occur for Fe-Si alloys₂The eutectoid decomposition reaction of ordered phase, it is raw Into the unordered phases of α-Fe and DO₃Ordered phase so that alloy becomes fragile and is difficult to deform.

For iron Si system alloy of the Si contents between 4.5~6.7%, commonly referred to as high silicon steel, wherein silicone content 6.5% High silicon steel it is mostly important.Its reason is Fe-Si alloy grains edge<100>The magnetostriction coefficient in direction is with the increase of Si contents And reduce, disappear substantially at about 6.3%, and<111>The magnetostriction coefficient in direction increases and increases with Si contents, about When 6.1% with<100>The magnetostriction coefficient in direction is equal so that high silicon steel shows excellent low in higher frequency operation Iron loss characteristic.

The transformer of normal operation can occur continuous uniform " drone " sound, this is because alternating current by transformer around Group when, in the core between generate periodically variable alternating flux, cause iron core magnetostriction and shake the sound sent.Greatly The sound that amount or large-scale iron core are sent in vibrations not only causes the loss of energy, also creates noise pollution.Especially It is to play particularly important role in the military aviation such as spacecraft, submarine and guided missile field, Fe-Si systems alloy.20th century 60 Age Mo, the alloy of Si contents 6.5% are appeared on No. 11 airships of Apollo as transformer material, are completed the mankind and are landed on the moon first Heroic undertaking.As it can be seen that high silicon steel is the environment-friendly type soft magnetic materials of a kind of consumption reduction of function admirable, noise reduction.

Compared to other alloys, the research and development process of high silicon steel is relatively very long.Late 1920s A.Schulze studies discovery first, and the iron Si system alloy of silicone content 6.5% has the almost nil characteristic of magnetostriction coefficient. In the 1980s, professor K.I.Arail etc. has found the high silicon steel alloy low compared to traditional Si content in exchange dynamic magnetic field In there is the magnetic conductivity of lower iron loss and higher.Hereafter between many decades, in order to overcome the brittleness of high silicon steel, in technology of preparing side There are many trials in face.As the special rolled method of jacket or temperature control, rapid solidification method, chemical vapour deposition technique (CVD method), Plasma chemical vapor deposition (PCVD methods), hot dipping ooze a diffusion annealing method, powder metallurgic method, microalloying and are modified Etc. various methods.

Wherein CVD is the successful example of comparison.NKK companies of Japan in 1988 have produced thickness for the first time using CVD technology It is the No yield point 6.5%Si steel discs of 400mm to spend for 0.1~0.5mm, width.Phase early 1990s, global first commercialization Can realize that the CVD production lines of continuous siliconising are developed, the product size of production can reach 0.1~0.3mm × 600mm。

The principle of CVD is：Under specific temperature conditions, silicon-containing gas (SiCl₄) can react generation Fe- with silicon strip Si compounds, and alloy is reached required content to alloy diffusion inside by elevated furnace temperature.Although oneself uses this Technology realizes small-scale industrialized production, but its scale and yield all can not much meet the need in international soft magnetic materials market Ask, and this preparation method technical process is sufficiently complex, energy consumption and of high cost, operating environment and its severe, it is impossible to meet ring Guaranteed request.

High silicon steel is " the steel art work ", its technology of preparing is all always and everywhere state-of-the-art steel and iron manufacturing technology, and It is the hot spot of development and exploitation.For 6.5%Si high silicon steel, its excellent magnetic performance and wide application prospect are even more to inhale Draw scientific worker and carry out substantial amounts of research-and-development activity.The development of preparation process and ripe and can be cost-effectively Production, is that 6.5%Si high silicon steel move towards to be commercialized widely applied key, also the always emphasis of research work.Once grope Go out simple, economic, effective, ripe preparation process, will just produce huge economic benefit and social benefit.

The content of the invention

The method for preparing high silicon steel band is sintered the object of the present invention is to provide a kind of powder tape casting and High temperature diffusion, The problem of being difficult to shaping for the Fe-Si alloy thin band materials of 4.5~6.7%Si contents, using water-atomized iron powder and Si contents as 50 ~70% HIGH-PURITY SILICON iron powder is raw material, then prepares certain thickness slab using powder curtain coating forming method, in degreasing, is burnt Porous, heterogeneous blank is formed after knot.Fe crystal grain containing substantial amounts of non-alloying in blank, has good plasticity, passes through Thin plate is obtained after crossing multi-pass cold rolling-sintering, is finally sintered using High temperature diffusion and obtains the high silicon steel band of homogeneous.

The present invention is achieved by the following technical solutions：Use subsphaeroidal water-atomized iron powder and fine Si contents for 50~70% HIGH-PURITY SILICON iron powder is raw material, forms Fe-4.5~6.7%Si mixed powders.Added again in mixed powder molten The components such as agent, dispersant, bonding agent, plasticizer, are made finely dispersed stable slurry, then certain thickness is made on casting machine Biscuit.Powder particle distributing homogeneity is high in biscuit made from tape casting, while water atomization Fe powder is with high-compressibility Big particle, larger volume ratio is occupied in mixed powder, larger volume ratio is occupied in mixed powder, adds fine Si Content be 50~70% HIGH-PURITY SILICON iron powder after will not significantly reduce its deformability.By powder curtain coating shaping slab 1060~ 1160 DEG C of temperature ranges carry out vacuum or protection of reducing atmosphere sintering, Fe powder particles is realized not exclusively sintering, and Si and Fe is real It is existing partially-alloyed, form the high silicon steel blank of incomplete alloying porous, that there is compressibility.Subsequently through repeatedly cold Roll, not exclusively sinter, the density rise of slab, plate thickness are reduced, and the alloying level of Si is also continuously improved.Finally 1250~ Vacuum or protection of reducing atmosphere sintering in 1320 DEG C of temperature ranges, realize the homogeneous alloy of high silicon steel with the help of thermal diffusion Change, obtain 0.1~0.5mm thickness containing 4.5~6.7%Si, density >=7.38g/cm³High silicon steel band.

The method of the present invention specifically comprises the following steps：

(1) raw material powder prepares

Using -100 mesh water-atomized iron powders, Fe >=99.0% in water-atomized iron powder, remaining for Si, Mn, P, S and other can not The impurity avoided, uses Si contents as 50~70% HIGH-PURITY SILICON iron powder, particle diameter≤6 μm, this ferrosilicon powder except containing 50~ Beyond 70%Si, major impurity is~0.24%Al ,~0.07%Ca and~0.02%C, remaining is Fe.

Water atomization Fe powder is a kind of widely used Industrial iron powder, has subsphaeroidal pattern, impurity content is less than reduction Fe Powder, has the compressibility and mobility of higher, is conducive to the Uniform Flow of powder curtain coating molding process powder.Water atomization Low impurity content is favourable to the soft magnetic characteristic of high silicon steel in Fe powder.

Fe-50~70%Si high purity ferrosilicons in process of setting there are two eutectic reactions, when rich Si sides are at 1207 DEG C Form the β-FeSi with tP3 structures₂With Si phase eutectic structures, form when rich Fe sides are at 1212 DEG C and tied with tP3 β-the FeSi of structure₂With the FeSi eutectic structures of cP8 structures；At 982 DEG C and 937 DEG C, also there are β-FeSi₂Decomposition and oC48- FeSi₂Two solid-state phase changes processes of formation of phase.Therefore it is easy in process of setting of the Fe-50~70%Si after refining crisp Change, form trickle Fe-Si or Si heterogeneous structures, it is easy to refine by Mechanical Crushing technique.Fe-50~70%Si is high-purity Ferrosilicon is crushed to≤6 μm of ferrosilicon powder, the Si phases in its actual tissue, FeSi₂, FeSi phases it is more tiny, be conducive to subsequent high temperature The thermal diffusion homogenization of Si elements, forms homogeneous Fe-6.5%Si single-phase alloys during sintering.Meanwhile exist in high purity ferrosilicon powder 30~50%Fe can effectively reduce the degree of oxidation of Si, be conducive to improve the product quality of high silicon steel.

By Fe-50~70%Si high purity ferrosilicons Mechanical Crushing to particle diameter≤6 μm, be conducive to it and be adhered to the table of reduction Fe powder Face is filled in the hole of reduction Fe powder, tiny Si, FeSi₂, FeSi phases Dispersed precipitate in blank, play structure refinement Strengthening and Toughening effect, be conducive to improve follow-up blank toughness, cracking do not easily caused in densification process is rolled.But Fe-50 Still contain a small amount of Si phases in~70%Si high purity ferrosilicons, Si is easily absorbing oxygen, and SiO is formed in exposed Si phase surfaces₂Film, Therefore in the preparation, storage and transfer process of Fe-50~70%Si HIGH-PURITY SILICON iron powders, and follow-up batch mixing, curtain coating, rolled Cheng Zhongying uses inert gas shielding, and used instrument must also take dehydration, drying process in advance.

On the premise of oxygen content is controlled, influence of the impurity such as Al, Ca, Mn to alloy magnetic property is little, during introduce The possibility of other alloying elements is also little.

(2) powder mixes

According to the ratio of Fe-4.5~6.7%Si, water atomization Fe powder and Fe-50~70%Si HIGH-PURITY SILICON iron powders, shape are weighed Into metal dust raw material, phosphoric acid and absolute ethyl alcohol are pressed 0.8~2.0:100 ratio is mixed to prepare passivating solution, by passivating solution with The metal dust raw material weighed is 0.4~0.6 according to quality:1 ratio mixing, after stirring 0.5~2h, it is blunt to be put into baking oven Change, baking temperature is 40~42 DEG C, and passivation time is 4~6h, obtains passivation powder.

Powder will be passivated with organic solution according to volume ratio 1:0.5~1 ratio mixing, 6~12h is stirred with mixer, Use 5~15min of ultrasonic disperse again, through screen filtration, the slurry for the even dispersion made after vacuum outgas, the viscosity of slurry for 40~ 80MPa.s。

Doctor-blade casting process is commonly called as scraper forming process, is a kind of important forming method for preparing large area film, is used Organic solvent, dispersant, plasticizer, the species such as binding agent it is various, above-mentioned pulping process is a kind of feasible method, not Represent preferable method.

(3) powder tape casting

During curtain coating environment temperature be 28~32 DEG C, will disperse slurry inject casting machine in, control casting machine speed be 0.1~ 0.5cm/s, the height of scraper is 1.2~2.4mm, and width is 100~300mm.

It is 30~40 DEG C to be cast biscuit drying temperature, and relative humidity is 30~60%, and the thickness of biscuit is after slurry drying 1.0~2.1mm, carries out curing process in a nitrogen atmosphere, and solidification temperature is 120~200 DEG C, and hardening time is 1~5h, with stove It is cooled to room temperature, the dry curtain coating slab dense structure of preparation, porosity is low, surfacing, because containing more plasticizer, bonding The organic matters such as agent, density are 6.3~6.8g/cm³。

(4) degreasing, sintering

Curtain coating slab is placed on surface to be coated with the support plate of MgO micro mists, is placed into vacuum degreasing, sintering furnace, 2h~4h is kept the temperature respectively using the programming rate of 2~5 DEG C/min, and in 200 DEG C, 400 DEG C, then will heat up to 1060~1160 DEG C 2~4h of heat preservation sintering, sintered blank density is 6.4~6.9g/cm³。

Uniform equiaxed grain structure is formed after sintering, matrix grain is about 70~100 μm, and crystal boundary has hole about~10 μm Gap, follow-up rolling and sintering can close.Only a small amount of the second phase about~2 μm is remained in matrix, with matrix Tissue has good interface cohesion, i.e., the face divided does not occur.These obvious second phases are certain richness Si phases, these richness Si phases Presence, reduce the Si contents of matrix so that matrix has high plastic deformation ability；Meanwhile itself and matrix Highly organized interface cohesion and Dispersed precipitate are conducive to subsequently homogenization diffusion.

Sintering temperature is too low, the connection being unfavorable between Fe powder particles and Si atoms permeatings, and sintering temperature is excessive then can be by In the diffusion into the surface of Fe, Si element, there is thick hole, be subsequently difficult to press, rolling densification is difficult to realize.

During sintering can powder curtain coating shaping blank can be placed with multilayer, but must separate between layers, to avoid sintering When slab shrink cause to crack.Programming rate should not be too fast during sintering, and multistage insulation can be set in temperature-rise period, de- to realize Gas, the effect of degreasing.Reproducibility or inert gas shielding degreasing, sintering can also be taken.W, Mo, resistance to can be used during sintering Hot steel etc. can also use the ceramic wafers such as corundum, zirconium oxide, but metallic plate thermal conductivity is good and sharp as support plate (or burning boat) Shunk in Even Sintering.

(5) cold rolling-sintering densification

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reaches 30 through multi- pass rolling to total reduction After~45%, in sintering furnace, 0.5~2h is re-sintered in 1060~1160 DEG C, after multiple cold rolling-sintering, the thickness of plate reaches To 0.1~0.5mm, density reaches 7.38~7.50g/cm³。

Since powder batch is porous organization, and there are deformable Fe phases, slab can bear cold-rolling deformation.Palette There is also more high Si phases in base, its performance is more crisp, therefore not above 8%, accumulation total reduction reaches amount under every time rolling 8~20 passages are taken around to 30~45%.

Since there are a large amount of holes and hard crisp phase, it is necessary to take and keep the temperature vacuum-sintering again at 1060 DEG C~1160 DEG C or go back Originality protective atmosphere sinters, to realize the reparation of the closing of pores and crackle, and the homogenization diffusion of a degree of Si elements.This When programming rate can be very fast, in 5~10 DEG C/min, can continuous warming, soaking time determines depending on thickness of slab, during thickness of slab >=1mm, protects The warm time is 1~2h；Thickness of slab is reduced to 0.5~1h in 0.1~1mm, soaking time.The accumulation drafts after sintering reaches every time , it is necessary to sinter 1 time again after 30~45%, 0.1~0.5mm is rolled down to from the biscuit of 1.0~2.1mm, takes around and burns again Knot 4~8 times.In addition, in order to make the density of plate reach 7.2g/cm³More than (about the 95% of solid density), it is also desirable to 4 times The above re-sinters.

Matrix after 2 cold rolling-sintering is about 100 μm of grain structure, there is a small amount of tiny hole.Matrix is brilliant Grain has two kinds of different contrasts, this is because Si contents are different and cause to corrode difference, low Si crystal grain is conducive in this kind tissue Machining deformation so that the thin plate of 0.1~0.5mm of manufacture is possibly realized.

(6) high temperature sintering is homogenized

Finally vacuum or restitutive protection 1~4h of atmosphere sintering in 1250~1320 DEG C of temperature ranges, in thermal diffusion Under effect, the homogenization of Si being realized, forming single-phase alloy, obtain the high silicon steel of homogeneous, the thickness of plate is almost after densification sintering It is constant, it is 0.1~0.5mm, density reaches 7.39~7.51g/cm³。

Organic solution described in step (2) is with 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, with asphalt mixtures modified by epoxy resin Fat is binding agent, and polyethylene glycol is plasticizer, and triethanolamine is dispersant, and the volume ratio of epoxy resin and polyethylene glycol presses 1: 1, then by mixed solvent quality be 50~70%, dispersant quality is 0.1%, the slurry that surplus is formed for binding agent and plasticizer Organic solution.

With high-energy ball milling or rush rotation method acquisition particle diameter≤6 μm HIGH-PURITY SILICON iron powder.

Step (5) is sintered when re-sintering for 1060~1160 DEG C under vacuum-sintering or restitutive protection's atmosphere, by 5~ 10 DEG C/min continuous warmings, during thickness of slab >=1mm, soaking time is 1~2h；Thickness of slab is reduced to 0.5 in 0.1~1mm, soaking time ~1h, after the accumulation drafts after sintering reaches 30~45% every time, sinters 1 time again, is rolled from the biscuit of 1.0~2.1mm To 0.1~0.5mm, it is necessary to sinter 4~8 times again.

Support plate described in step (4) burns boat using W, Mo, corundum or zirconia ceramics.

Placement sintering plate can be overlapped during high temperature sintering, but interlayer must be laid with MgO powder, and W, Mo and ceramics can be used to burn Boat.But plate must tile placement, tablet weight can be placed on plate, prevents from deforming in sintering process.

In addition to Si contents, content of element such as grain size, crystal grain orientation, C etc. also has the magnetic behavior of high silicon steel Large effect, can subsequently be annealed, the technological means such as normalizing treatment is controlled by by wet hydrogen.

Essence of the invention is by with the addition of granularity≤6 in the water atomization Fe powder of the big volumetric portion with good plasticity μm Fe-50~70%Si high-purity powders, using organic curtain coating system, it is molding compound to form a kind of achievable powder curtain coating Material；The uniform slab of density, Tissue distribution is prepared using tape casting；By not exclusively sintering, realize Fe powder particles Not exclusively connection, and Si and Fe realizes partially-alloyed, the high silicon steel of porous, with compressibility the incomplete alloying of formation Blank；Subsequently through multi-pass cold rolling and sintering, structural homogenity and compactness are improved；Again by high-temperature diffusion process, realize The homogenization of Si, so as to obtain the high silicon steel band of high quality.This method realizes technical process certainly by technique and equipment Design Dynamicization, continuous production, can be mass-produced 0.1~0.5mm thickness, density >=7.38g/cm³High silicon steel band.

Brief description of the drawings

Fig. 1 is the metallograph after the powder tape casting base sintering of the embodiment of the present invention 2；

Fig. 2 is metallograph of the plate of the embodiment of the present invention 3 after 2 cold rolling-sintering；

Fig. 3 is XRD diffraction curve figures after the powder tape casting base high temperature sintering of the embodiment of the present invention 4.

Embodiment

The present invention is described in further detail with reference to the accompanying drawings and detailed description.

Embodiment 1

By the water atomization Fe powder of -100 mesh and the Fe-70%Si high-purity powders of granularity≤6 μm according to 90.43:9.57 ratio Example mixing, forms the mixed-powder of Fe-6.7%Si.Phosphoric acid and absolute ethyl alcohol are pressed 0.8:100 ratio is mixed to prepare passivation Liquid.By passivating solution and the metal dust raw material weighed according to 0.4:1 ratio mixing, after stirring 0.5h with mixer, is put into Baking oven is passivated, and baking temperature is 40 DEG C, passivation time 4h, obtains passivation powder.

With 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, is increasing by binding agent, polyethylene glycol of epoxy resin Agent is moulded, triethanolamine is dispersant.The volume ratio of epoxy resin and polyethylene glycol presses 1:1, the addition of mixed solvent is 60%, the addition of dispersant is 0.1%, forms the organic solution of slurry.Powder will be passivated with organic solution according to volume ratio 1: 0.5 ratio mixing, 6h is stirred with mixer, then with ultrasonic disperse 5min, through screen filtration, made after vacuum outgas uniformly more Scattered slurry, the viscosity of slurry is 40MPa.s.

Environment temperature is 28 DEG C during curtain coating, and disperse slurry is injected in casting machine, and it is 0.5cm/s to control casting machine speed, The height of scraper is 2.4mm, and width is about 100mm.

It is 40 DEG C to be cast biscuit drying temperature, relative humidity 30%, and the thickness of biscuit is 2.1mm after slurry drying. Curing process is carried out under nitrogen atmosphere, solidification temperature is 200 DEG C, hardening time 5h, cools to room temperature with the furnace, and curtain coating slab is close Spend for 6.3g/cm³。

Curtain coating slab is placed on surface to be coated with the molybdenum plate of MgO micro mists, is placed into vacuum degreasing, sintering furnace.Adopt With the programming rate of 2 DEG C/min, and 4h is kept the temperature respectively in 200 DEG C, 400 DEG C.Then will heat up to 1060 DEG C of heat preservation sintering 4h.Burn It is 6.4g/cm to tie base density³。

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reaches 30 through multi- pass rolling to total reduction After~45%, then in vacuum sintering furnace, in 1060 DEG C of heat preservation sinterings.With 5 DEG C/min speed continuous warmings, soaking time regards plate Thickness determines, during thickness of slab >=1mm, soaking time 2h；Thickness of slab is in 0.1~1mm, soaking time 1h.Specific pressure-annealing schedule For：2.1mm → 1.52mm → 1.02mm → 0.71mm → 0.49mm, i.e., after 4 cold rollings and 3 sintering, the thickness of plate reaches To 0.49mm, density reaches 7.38g/cm³。

For above-mentioned cold rolling made-up belt in 1320 DEG C of vacuum-sintering 1h, it is about 0.50mm, density 7.39g/cm to obtain thickness³, Si Content is the 6.7% high silicon steel of single-phase homogeneous.

Embodiment 2

By the water atomization Fe powder of -100 mesh and the Fe-50%Si high-purity powders of granularity≤10 μm according to 91:9 ratio is mixed Close, form the mixed-powder of Fe-4.5%Si.Phosphoric acid and absolute ethyl alcohol are pressed 2.0:100 ratio is mixed to prepare passivating solution.Will Passivating solution and the metal dust raw material that has weighed are according to 0.6:1 ratio mixing, after stirring 2h with mixer, it is blunt to be put into baking oven Change, baking temperature is 42 DEG C, passivation time 6h, obtains passivation powder.

With 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, is increasing by binding agent, polyethylene glycol of epoxy resin Agent is moulded, triethanolamine is dispersant.The volume ratio of epoxy resin and polyethylene glycol presses 1:1, the addition of mixed solvent is 60%, the addition of dispersant is 0.1%, forms the organic solution of slurry.Powder will be passivated with organic solution according to volume ratio 1:1 Ratio mixing, stir 12h with mixer, then with ultrasonic disperse 15min, through screen filtration, made after vacuum outgas uniformly more Scattered slurry, the viscosity of slurry is 80MPa.s.

Environment temperature is 32 DEG C during curtain coating, and disperse slurry is injected in casting machine, and it is 0.1cm/s to control casting machine speed, The height of scraper is 1.2mm, and width is about 300mm.

It is 30 DEG C to be cast biscuit drying temperature, relative humidity 60%, and the thickness of biscuit is 1.0mm after slurry drying. Curing process is carried out under nitrogen atmosphere, solidification temperature is 120 DEG C, hardening time 1h, cools to room temperature with the furnace, and curtain coating slab is close Spend for 6.8g/cm³。

Curtain coating slab is placed on surface to be coated with the molybdenum plate of MgO micro mists, is placed into vacuum degreasing, sintering furnace.Adopt With the programming rate of 5 DEG C/min, and 2h is kept the temperature respectively in 200 DEG C, 400 DEG C.Then will heat up to 1160 DEG C of heat preservation sintering 2h.Burn It is 6.9g/cm to tie base density³。

Uniform equiaxed grain structure is formed after sintering, sees Fig. 1.Matrix grain is about 70~100 μm, and crystal boundary exists about~10 μm hole, follow-up rolling and sintering can close.Only a small amount of the second phase about~2 μm is remained in matrix, There is good interface cohesion with matrix, i.e., the face divided do not occur.These obvious second phases are certain richness Si phases, these The presence of rich Si phases, reduces the Si contents of matrix so that matrix has high plastic deformation ability；Meanwhile its Good interface cohesion and Dispersed precipitate are conducive to subsequently homogenization diffusion with matrix.

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reaches 30 through multi- pass rolling to total reduction After~45%, then in vacuum sintering furnace, in 1160 DEG C of heat preservation sinterings.With 10 DEG C/min speed continuous warmings, soaking time is 1h.Specifically pressure-annealing schedule is：1.0mm → 0.65mm → 0.39mm → 0.25mm → 0.17mm → 0.13mm → 0.10mm, I.e. after 6 cold rollings and 5 sintering, the thickness of plate reaches 0.10mm, and density reaches 7.50g/cm³。

For above-mentioned cold rolling made-up belt in 1250 DEG C of vacuum-sintering 4h, it is about 0.10mm, density 7.51g/cm to obtain thickness³, Si Content is the 4.5% high silicon steel of single-phase homogeneous.

Embodiment 3

By the water atomization Fe powder of -100 mesh and the Fe-60%Si high-purity powders of granularity≤6 μm according to 89.17:10.83 ratio Example mixing, forms the mixed-powder of Fe-6.5%Si.Phosphoric acid and absolute ethyl alcohol are pressed 1.0:100 ratio is mixed to prepare passivation Liquid.By passivating solution and the metal dust raw material weighed according to 0.5:1 ratio mixing, after stirring 1h with mixer, is put into baking Case is passivated, and baking temperature is 40 DEG C, passivation time 5h, obtains passivation powder.

With 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, is increasing by binding agent, polyethylene glycol of epoxy resin Agent is moulded, triethanolamine is dispersant.The volume ratio of epoxy resin and polyethylene glycol presses 1:1, the addition of mixed solvent is 60%, the addition of dispersant is 0.1%, forms the organic solution of slurry.Powder will be passivated with organic solution according to volume ratio 1: 0.6 ratio mixing, 8h is stirred with mixer, then with ultrasonic disperse 7min, through screen filtration, made after vacuum outgas uniformly more Scattered slurry, the viscosity of slurry is 60MPa.s.

Environment temperature is 30 DEG C during curtain coating, and disperse slurry is injected in casting machine, and it is 0.3cm/s to control casting machine speed, The height of scraper is 1.4mm, and width is about 250mm.

It is 35 DEG C to be cast biscuit drying temperature, relative humidity 45%, and the thickness of biscuit is 1.2mm after slurry drying. Curing process is carried out under nitrogen atmosphere, solidification temperature is 160 DEG C, hardening time 3h, cools to room temperature with the furnace, and curtain coating slab is close Spend for 6.36g/cm³。

Curtain coating slab is placed on surface to be coated with the corundum plate of MgO micro mists, the degreasing of hydrogen tube furnace is placed into, burns Knot.Using the programming rate of 3 DEG C/min, and 2h, 400 DEG C of insulation 3h are kept the temperature at 200 DEG C.Then it will heat up to 1150 DEG C of insulations and burn Tie 3h.Sintered blank density is 6.46g/cm³。

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reaches 30 through multi- pass rolling to total reduction After~45%, then in hydrogen tube furnace, in 1150 DEG C of heat preservation sintering 1h.With 6 DEG C/min speed continuous warmings.Specific pressure- Annealing schedule is：1.2mm → 0.96mm → 0.70mm → 0.45mm → 0.27mm, i.e., after 4 cold rollings and 3 sintering, plate Thickness reach 0.27mm, density reaches 7.40g/cm³。

Fig. 2 is shown in metallographic structure after 2 cold rolling-sintering, and matrix is about 100 μm of grain structure, exists a small amount of thin Small hole.Matrix grain has two kinds of different contrasts, this is because Si contents are different and cause to corrode difference, in this kind tissue Low Si crystal grain is conducive to machining deformation so that the thin plate of 0.1~0.5mm of manufacture is possibly realized.

For above-mentioned cold rolling made-up belt in 1300 DEG C of vacuum-sintering 2h, it is about 0.27mm, density 7.41g/cm to obtain thickness³, Si Content is the 6.5% high silicon steel of single-phase homogeneous.

Embodiment 4

By the water atomization Fe powder of -100 mesh and the Fe-62%Si high-purity powders of granularity≤10 μm according to 90.64:9.36 ratio Example mixing, forms the mixed-powder of Fe-5.8%Si.Phosphoric acid and absolute ethyl alcohol are pressed 1.2:100 ratio is mixed to prepare passivation Liquid.By passivating solution and the metal dust raw material weighed according to 0.6:1 ratio mixing, after stirring 1h with mixer, is put into baking Case is passivated, and baking temperature is 42 DEG C, passivation time 6h, obtains passivation powder.

With 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, is increasing by binding agent, polyethylene glycol of epoxy resin Agent is moulded, triethanolamine is dispersant.The volume ratio of epoxy resin and polyethylene glycol presses 1:1, the addition of mixed solvent is 60%, the addition of dispersant is 0.1%, forms the organic solution of slurry.Powder will be passivated with organic solution according to volume ratio 1: 0.7 ratio mixing, stirs 9h, then with ultrasonic disperse 10min, through screen filtration, that is made after vacuum outgas is uniform with mixer The slurry of disperse, the viscosity of slurry is 55MPa.s.

Environment temperature is 30 DEG C during curtain coating, and disperse slurry is injected in casting machine, and it is 0.3cm/s to control casting machine speed, The height of scraper is 1.8mm, and width is about 150mm.

It is 30 DEG C to be cast biscuit drying temperature, relative humidity 50%, and the thickness of biscuit is 1.6mm after slurry drying. Curing process is carried out under nitrogen atmosphere, solidification temperature is 160 DEG C, hardening time 4h, cools to room temperature with the furnace, and curtain coating slab is close Spend for 6.5g/cm³。

Curtain coating slab is placed on surface to be coated with the corundum plate of MgO micro mists, the degreasing of hydrogen tube furnace is placed into, burns Knot.Using the programming rate of 4 DEG C/min, and 3h, 400 DEG C of insulation 2h are kept the temperature at 200 DEG C.Then it will heat up to 1130 DEG C of insulations and burn Tie 2h.Sintered blank density is 6.66g/cm³。

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reaches 30 through multi- pass rolling to total reduction After~45%, then in hydrogen tube furnace, in 1130 DEG C of heat preservation sintering 0.5h.With 8 DEG C/min speed continuous warmings.Specific pressure Under-annealing schedule is：1.6mm → 1.21mm → 0.96mm → 0.72mm → 0.46mm → 0.32mm → 0.21mm is that is, cold through 7 times Roll with after 6 sintering, the thickness of plate reaches 0.21mm, and density reaches 7.42g/cm³。

For above-mentioned cold rolling made-up belt in 1250 DEG C of vacuum-sintering 2h, it is about 0.22mm, density 7.43g/cm to obtain thickness³, Si Content is that 5.8%, Fig. 3 is its XRD analysis figure, is the high silicon steel of single-phase homogeneous.

Claims

1. a kind of method that powder tape casting prepares high silicon steel band with High temperature diffusion sintering, it is characterised in that including following step Suddenly：

(1) raw material powder prepares

Using -100 mesh water-atomized iron powders, Fe >=99.0% in water-atomized iron powder, remaining is Si, Mn, P, S and other are inevitable Impurity, use Si contents as 50~70% HIGH-PURITY SILICON iron powder, particle diameter≤6 μm, major impurity is~0.24%Al ,~ 0.07%Ca and~0.02%C, remaining is Fe；

(2) powder mixes

According to the ratio of Fe-4.5~6.7%Si, water atomization Fe powder and Fe-50~70%Si HIGH-PURITY SILICON iron powders are weighed, forms gold Belong to powder raw material, phosphoric acid and absolute ethyl alcohol are pressed 0.8~2.0:100 ratio is mixed to prepare passivating solution, by passivating solution with weighing Good metal dust raw material is 0.4~0.6 according to quality:1 ratio mixing, after stirring 0.5~2h, is put into baking oven passivation, dries Roasting temperature is 40~42 DEG C, and passivation time is 4~6h, obtains passivation powder；

Powder will be passivated with organic solution according to volume ratio 1:0.5~1 ratio mixing, stirs 6~12h, then with ultrasonic disperse 5 ~15min, through screen filtration, the slurry for the even dispersion made after vacuum outgas, the viscosity of slurry is 40~80MPa.s；

(3) powder tape casting

During curtain coating environment temperature be 28~32 DEG C, will disperse slurry inject casting machine in, control casting machine speed be 0.1~ 0.5cm/s, the height of scraper is 1.2~2.4mm, and width is 100~300mm；

It is 30~40 DEG C to be cast biscuit drying temperature, and relative humidity is 30~60%, after slurry drying the thickness of biscuit for 1.0~ 2.1mm, carries out curing process in a nitrogen atmosphere, and solidification temperature is 120~200 DEG C, and hardening time is 1~5h, furnace cooling To room temperature, the dry curtain coating slab density of preparation is 6.3~6.8g/cm³；

(4) degreasing, sintering

Curtain coating slab is placed on surface to be coated with the support plate of MgO micro mists, is placed into vacuum degreasing, sintering furnace, using 2 The programming rate of~5 DEG C/min, and 2h~4h is kept the temperature respectively in 200 DEG C, 400 DEG C, then it will heat up to 1060~1160 DEG C of guarantors Temperature 2~4h of sintering, sintered blank density is 6.4~6.9g/cm³；

(5) cold rolling-sintering densification

By above-mentioned sintering slab rolled thickness reduction, single pass rolling reduction≤8%, reach 30 through multi- pass rolling to total reduction~ After 45%, in sintering furnace, 0.5~2h is re-sintered in 1060~1160 DEG C, after multiple cold rolling-sintering, the thickness of plate reaches 0.1~0.5mm, density reach 7.38~7.50g/cm³；

(6) high temperature sintering is homogenized

Vacuum or restitutive protection 1~4h of atmosphere sintering in 1250~1320 DEG C of temperature ranges, it is real under the action of thermal diffusion The homogenization of existing Si, forms single-phase alloy, obtains the high silicon steel of homogeneous, and thickness 0.1~0.5mm of plate, close after densification sintering Degree reaches 7.39~7.51g/cm³。

2. the method that powder tape casting as claimed in claim 1 prepares high silicon steel band with High temperature diffusion sintering, its feature It is：Organic solution described in step (2) is with 10:1.0 methyl ethyl ketone and absolute ethyl alcohol is mixed solvent, using epoxy resin as Binding agent, polyethylene glycol are plasticizer, and triethanolamine is dispersant, and the volume ratio of epoxy resin and polyethylene glycol presses 1:1, then It is 50~70% by mixed solvent quality, dispersant quality is 0.1%, and surplus is organic for the slurry that binding agent and plasticizer are formed Solution.

3. the method that powder tape casting as claimed in claim 1 prepares high silicon steel band with High temperature diffusion sintering, its feature It is：With high-energy ball milling or rush rotation method obtain particle diameter≤6 μm HIGH-PURITY SILICON iron powder.

4. the method that powder tape casting as claimed in claim 1 prepares high silicon steel band with High temperature diffusion sintering, its feature It is：Step (5) sinters, by 5~10 when re-sintering for 1060~1160 DEG C under vacuum-sintering or restitutive protection's atmosphere DEG C/min continuous warmings, during thickness of slab >=1mm, soaking time is 1~2h；Thickness of slab in 0.1~1mm, soaking time is reduced to 0.5~ 1h, after the accumulation drafts after sintering reaches 30~45% every time, sinters 1 time, is rolled down to from the biscuit of 1.0~2.1mm again 0.1~0.5mm, it is necessary to sinter 4~8 times again.

5. the method that powder tape casting as claimed in claim 1 prepares high silicon steel band with High temperature diffusion sintering, its feature It is：Overlapping places sintering plate during high temperature sintering, and interlayer is laid with MgO powder.

6. the method that powder tape casting as claimed in claim 1 prepares high silicon steel band with High temperature diffusion sintering, its feature It is：Support plate described in step (4) burns boat using W, Mo, corundum or zirconia ceramics.