CN115233111B - High-performance powder sintered alnico magnetic material and preparation method thereof - Google Patents

High-performance powder sintered alnico magnetic material and preparation method thereof Download PDF

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CN115233111B
CN115233111B CN202210668714.4A CN202210668714A CN115233111B CN 115233111 B CN115233111 B CN 115233111B CN 202210668714 A CN202210668714 A CN 202210668714A CN 115233111 B CN115233111 B CN 115233111B
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CN115233111A (en
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冯建涛
赵宇
于京京
彭银华
蒋洪炯
舒增昌
陈亚利
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Hangzhou Permanent Magnet Group Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/001—Heat treatment of ferrous alloys containing Ni
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • C22C33/0285—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5% with Cr, Co, or Ni having a minimum content higher than 5%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • C22C38/105—Ferrous alloys, e.g. steel alloys containing cobalt containing Co and Ni
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper

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Abstract

The invention discloses a high-performance powder sintered alnico magnetic material and a preparation method thereof, wherein the high-performance powder sintered alnico magnetic material comprises the following components in percentage by mass: 5 to 7 weight percent of Al, 12 to 14 weight percent of Ni, 3 to 4 weight percent of Cu, 36 to 38 weight percent of Co, 0.5 to 0.8 weight percent of Nb, 5.5 to 7 weight percent of Ti and the balance of Fe. The invention fully considers the hardness and melting point characteristics of each component alloy, improves the hardness by adjusting the composition and granularity of the alloy and annealing, adapts alloy components with approximate melting point and moderate hardness, is beneficial to forming a plurality of coarse grains in the subsequent rapid powder preparation and sintering processes, and improves the magnetic property; the invention fully utilizes the characteristic that the alloy is more stable than a simple substance, particularly the Al alloy, improves the stability of the Al content, cancels hydrogen reduction and reduces the production cost.

Description

High-performance powder sintered alnico magnetic material and preparation method thereof
Technical Field
The invention belongs to the technical field of permanent magnet materials, and particularly relates to a high-performance powder sintered alnico magnetic material and a preparation method thereof.
Background
The alnico permanent magnet material is generally divided into cast alnico and sintered alnico according to the manufacturing process, the sintered alnico magnetic steel adopts a pressing-sintering process, and the metal yield can reach more than 95 percent. Because the crystal grain is fine and has no casting defect, compared with the cast alnico material, the sintered alnico magnetic steel has high mechanical property, is suitable for the environment with larger vibration and impact, can be manufactured into various shapes by powder pressing, and is widely applied to various small devices. And because the chemical components are accurate and the structure is uniform, the performance of the magnetic steel is uniform and stable. In view of the technological and economic advantages of sintering alnico, alnico has been widely used in the electrical instruments, radio and automatic control industries.
In the existing preparation process of powder sintering alnico, considering that the melting point of aluminum is very low (660 ℃), the oxidation resistance is poor, and the melting points of other components of the alloy are much higher than that of the aluminum in the sintering process, so the aluminum is often added in the form of intermediate alloy, such as iron-aluminum, cobalt-aluminum and the like. In addition, in order to obtain larger coarse grains and better magnetic performance, the conventional process generally adopts four elemental powders (nickel powder, cobalt powder, iron powder and copper powder) and four alloy powders (iron-aluminum alloy, cobalt-aluminum alloy, niobium-iron alloy and ferrotitanium alloy) to be respectively weighed and finally uniformly mixed to prepare the powder sintered alnico magnetic steel. The simple substance metal powder is generally purchased directly from a raw material factory, and the price of the simple substance metal powder is more expensive than that of corresponding metal sheets and the like (for example, the cobalt powder is 8-10 ten thousand per ton more expensive than the cobalt sheets, and the nickel powder is 5-6 ten thousand per ton more expensive than the nickel sheets).
In addition, in the subsequent process of preparing powder sintering alnico, the elemental metal powder generally needs to be provided with a separate ammonia decomposition device to provide hydrogen for thermal reduction, so that the purity of the elemental metal powder is ensured, namely the elemental metal powder can be directly mixed for use only by hydrogen thermal reduction. In addition, considering the process of preparing the simple substance powder in a raw material plant, the simple substance powder is generally prepared by a method of reducing oxides or carbonic acid compounds through heat treatment (such as cobalt powder), so the particle size of the simple substance powder is wide, the appearance is porous and loose, the particle size distribution difference of the simple substance powder and the alloy powder subjected to ball milling and granulation in the subsequent sintering process is large, the temperature is difficult to fit, and the sintered alnico product has the phenomena of deformation, sand sticking and the like, thereby influencing the qualification rate.
Patent CN111020341B discloses a production process of powder sintering alnico permanent magnetic alloy, and the formula of the alloy comprises four simple substance powders and two alloy powders. And after the elementary substance powder is mixed, the mixture needs to be reduced for 2 hours at 550 ℃ by using hydrogen to prevent the elementary substance from being oxidized. The CoAl alloy and the TiFe alloy in the alloy powder need to be smelted separately and then prepared by jet milling, the whole process is complicated and long, and a high-risk and high-energy-consumption process of a hydrogen reduction process is inevitably needed.
Disclosure of Invention
The invention aims to provide a high-performance powder sintered alnico magnetic material and a preparation method thereof.
In order to achieve the above object, according to one aspect of the present invention, there is provided a high performance powder sintered alnico magnetic material, comprising the following components in mass percent: 5-7wt% of Al, 12-14wt% of Ni, 3-4wt% of Cu, 36-38wt% of Co, 0.5-0.8wt% of Nb, 5.5-7wt% of Ti and the balance of Fe.
According to the invention, the high-performance powder sintered alnico magnetic material comprises the following components in percentage by mass: 6.0 to 6.5 weight percent of Al, 12.8 to 13.5 weight percent of Ni, 3.5 to 4 weight percent of Cu, 36.5 to 37.3 weight percent of Co, 0.6 to 0.7 weight percent of Nb, 6.0 to 6.5 weight percent of Ti, and the balance of Fe.
According to another aspect of the present invention, there is also provided a method for preparing a high performance powder sintered alnico magnetic material, comprising the steps of:
s1, weighing a certain mass part of simple substances and alloys, wherein the mass part of the simple substances and alloys is 100, and the mass part of the simple substances and alloys is as follows: 5-7 parts of Ni sheet, 12-14 parts of Cu sheet, 3-4 parts of Co sheet: 36-38 parts of NbFe:1-1.5 parts of Ti:5.5-7.0 parts; the balance of Fe rods;
s2, putting the weighed metal simple substances Cu, ti and Fe rods and 22-25 parts of Co and alloy NbFe into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to be 1600 +/-20 ℃, casting the refined material to obtain a rapid hardening melt-spun piece A, and then carrying out vacuum annealing treatment;
s3, mixing the weighed Al ingot and the rest Co slices in a Co slice: putting the Al ingot = 1 in 1560 +/-20 ℃ of weight ratio, and carrying out vacuum melting, and quickly solidifying and throwing to obtain a throwing sheet B; putting the rest Al ingot and the weighed Ni into 1560 +/-20 ℃ for vacuum smelting, and quickly solidifying and throwing to obtain throwing pieces C; carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C;
s4, placing the annealed flappers A, B and C into a mortar, crushing by using a punch, sieving coarse crushing powder obtained by crushing to obtain alloy coarse powder, and then finely crushing by using an airflow mill to prepare powder;
s5, adding 0.5wt% of aluminum stearate into the prepared airflow milled powder, continuously mixing uniformly, and performing compression molding to obtain a compression blank with a corresponding shape;
s6, sintering the pressed blank in vacuum, cooling and discharging to obtain a sintered blank; carrying out magnetic field heat treatment on the sintered blank, and then carrying out four-stage tempering to obtain a semi-finished blank; and (4) finely grinding the semi-finished blank to remove oxide skin flaws on the surface to obtain the high-performance powder sintered alnico magnetic material.
According to the invention, the annealing treatment process in the steps S2 and S3 comprises the following steps: heating to 1000-1060 ℃ at room temperature at a heating rate of 60-100 ℃/h, preserving heat for 3-4 h, then cooling to 150 ℃ at a rate of 20-60 ℃/h, discharging, and cooling to room temperature.
For example, the annealing process in step S2 is: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a rate of 20 ℃/h, discharging and cooling to room temperature; or
Heating to 1020 ℃ at room temperature at the heating rate of 80 ℃/h, preserving heat for 3h, then cooling to 150 ℃ at the temperature of 40 ℃/h, discharging, and cooling to room temperature; or
Heating to 1040 ℃ at room temperature at a heating rate of 100 ℃/h, preserving heat for 2h, then cooling to 150 ℃ at a heating rate of 60 ℃/h, discharging, and cooling to room temperature.
According to the invention, the rapid hardening melt spinning conditions are as follows: the rotation speed of the copper roller is 50 +/-10 r/min, and the thickness of the flail is 0.20-0.35 mm. Preferably, the Nb content in the NbFe alloy is 65wt%, and the purity of other elementary substance alloys is more than or equal to 99.5%.
According to the invention, the gas stream is milledThe powder process comprises the following steps: the sorting rotation speed is 1600-2000r/min, the pressure of the grinding chamber is 610-630KPa, and the weight of the grinding chamber is 4-6Kg. Preferably, the powder obtained by the jet mill has a particle size D 50 ：20～22μm，D 90 /D 10 And (5.6-6.2). For example, the powder particle size D of the jet mill powder 50 ：20μm，D 90 /D 10 =5.8; particle diameter D of powder 50 ：21μm，D 90 /D 10 =6.0; particle diameter D of the powder 50 ：22μm，D 90 /D 10 ＝6.2。
Preferably, a nitrogen pipe is arranged on a pressure head of the punching machine, the nitrogen pipe introduces nitrogen into the mortar in the punching process, and a cooling device is arranged around the mortar.
According to the invention, 0.4 to 0.6 wt.% of aluminium stearate is added to the gas stream milling powder obtained in step S5; for example, 0.4wt%,0.45wt%,0.5wt%,0.55wt%,0.6wt%. Preferably, the pressure applied in the press forming is 20 to 30t. Preferably, the coarsely crushed powder obtained by crushing is passed through a 50-mesh sieve every 2 to 3 minutes.
According to the present invention, the step of vacuum sintering the pressed blank in step S6 includes: heating to 450-500 ℃ at room temperature at the heating rate of 3-5 ℃/min, and keeping the temperature for 1-2 hours; then heating to 800-900 ℃ and preserving heat for 1-2 hours, and continuing heating to 1290-1320 ℃ and preserving heat for 0.2-0.5 hours; then continuously heating to 1330-1350 ℃, preserving the heat for 4.5-6 hours, and cooling to room temperature along with the furnace.
For example, heating to 500 ℃ at a heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing heating to 1300 ℃ and preserving heat for 0.2h, then continuing heating to 1340 ℃, preserving heat for 6h, and finally cooling to room temperature along with the furnace; or
Heating to 450 ℃ at the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃ and preserving heat for 2h, continuing heating to 1290 ℃ and preserving heat for 0.3h, then continuing heating to 1330 ℃, preserving heat for 5h, and finally cooling to room temperature along with the furnace; or
Heating to 450 ℃ at the heating rate of 3 ℃/min, preserving heat for 2h, then heating to 800 ℃ and preserving heat for 2h, continuing heating to 1320 ℃ and preserving heat for 0.3h, then continuing heating to 1350 ℃, preserving heat for 4.5h, and finally cooling to room temperature along with the furnace.
According to the invention, the step of magnetic field heat treatment of the sintered blank comprises: pretreating the sintered blank in a box-type resistance furnace at 800-900 ℃ for 30-50 min; then transferring the blank to a high-temperature furnace at 1260-1280 ℃, and carrying out solid melting heat treatment for 20-40 min; taking out the blank, air-cooling for 1-5 minutes, transferring the blank into a magnetic field, and carrying out isothermal heat treatment at 750-850 ℃ for 20-30 min; taking out and cooling to room temperature.
According to the invention, the method also comprises the step of four-stage tempering of the sintered blank after the magnetic field heat treatment: firstly preserving heat for 3-4 hours at 630-650 ℃, then preserving heat for 6-8 hours at 600-620 ℃, cooling to 570-590 ℃, preserving heat for 8-10 hours, continuously cooling to 540-560 ℃, preserving heat for 8-10 hours, and finally cooling along with the furnace to obtain a semi-finished product blank.
For example, firstly preserving the heat at 640 ℃ for 4h, preserving the heat at 610 ℃ for 8h, continuously preserving the heat at 580 ℃ for 8h, preserving the heat at 550 ℃ for 10h, and finally cooling along with the furnace; or firstly preserving the heat at 635 ℃ for 3h, preserving the heat at 620 ℃ for 7h, continuously preserving the heat at 585 ℃ for 9h, preserving the heat at 555 ℃ for 9h, and finally cooling along with the furnace; or firstly preserving the heat at 630 ℃ for 3h, preserving the heat at 600 ℃ for 7h, continuously preserving the heat at 570 ℃ for 9h, preserving the heat at 540 ℃ for 9h, and finally cooling along with the furnace.
The invention has the beneficial effects that:
1) The invention cancels the use of simple substance powder, selects the alloy with low cost and stable property, changes the process flow of the existing powder sintering, simplifies the procedure, breaks through the limitation of the prior alloy on production due to difficult crushing and powder preparation, adopts the process of eliminating high energy consumption and high safety evaluation requirements such as ammonia decomposition and the like, prepares the powder sintering alnico alloy material by preparing three alloy raw materials and assisting airflow milling powder preparation and sintering process improvement, and obtains a novel powder sintering alnico material with excellent magnetic property.
2) The invention fully considers the characteristics of the hardness and the melting point of each component alloy, improves the hardness by annealing and adapting to alloy components with approximate melting point and moderate hardness by adjusting the components of the alloy and the granularity of powder prepared by air flow milling, is beneficial to forming a plurality of coarse grains in the subsequent rapid powder preparation and sintering processes, and improves the magnetic property.
3) The invention fully utilizes the characteristic of more simple substance stability of the alloy, particularly the Al alloy, improves the stability of Al content, breaks through the limitation that the conventional Al-Ni-Co alloy is difficult to crush and cannot be prepared into powder by adjusting the composition and the proportion of a plurality of raw material alloys and improving by an annealing process, improves the particle size range and distribution of each alloy composition and improves the magnetic property by subsequently preparing powder by airflow milling, cancels hydrogen reduction in the preparation process, reduces the production cost, and provides a quick and low-cost manufacturing process for powder sintering of the Al-Ni-Co alloy.
Drawings
FIG. 1 is a photograph of an AlNiCo formed blank prepared in example 1.
FIG. 2 is a photograph of an AlNiCo formed blank prepared in example 4.
FIG. 3 is a photograph of an AlNiCo formed blank prepared in example 5.
Detailed Description
The method of the present invention is illustrated by the following specific examples, but the present invention is not limited thereto, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included within the scope of the present invention. The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.
The invention provides a high-performance powder sintered alnico magnetic material, which comprises the following components in percentage by weight: 5-7wt% of Al, 12-14wt% of Ni, 3-4wt% of Cu, 36-38wt% of Co, 0.5-0.8wt% of Nb, 5.5-7wt% of Ti and the balance of Fe.
Preferably, the high-performance powder sintered alnico magnetic material comprises the following components in percentage by weight: 6.0 to 6.5 weight percent of Al, 12.8 to 13.5 weight percent of Ni, 3.5 to 4 weight percent of Cu, 36.5 to 37.3 weight percent of Co, 0.6 to 0.7 weight percent of Nb, 6.0 to 6.5 weight percent of Ti, and the balance of Fe.
According to the invention, through optimizing and blending the alloy composition and the grain size, and smelting and airflow milling the three alloys to prepare the powder, the sintered alnico material with better magnetic performance than that of the conventional method is obtained, the application range is enlarged, the market occupation ratio is enlarged, and the method has very important significance.
According to another aspect of the present invention, there is also provided a method for preparing a high performance powder sintered alnico magnetic material, comprising the steps of:
s1, weighing: weighing a certain mass part of simple substances and alloys, wherein the mass part is 100 parts, wherein the mass part of the Al ingot is as follows: 5-7 parts of Ni sheet, 12-14 parts of Cu sheet, 3-4 parts of Co sheet: 36-38 parts of NbFe:1-1.5 parts of Ti:5.5-7.0 parts; the balance of Fe rods;
s2, smelting, quick hardening and throwing: putting the weighed metal simple substance Cu, ti and Fe rods and 22-25 parts of Co and alloy NbFe into a vacuum rapid hardening flail furnace, vacuumizing, heating, controlling the smelting temperature to be 1600 +/-20 ℃, casting the refined material to obtain a rapid hardening flail A, and then carrying out vacuum annealing treatment;
s3, weighing and smelting: the remaining Co was weighed as Co flakes: the ratio of Al ingot =3 is 1560 +/-20 ℃, vacuum melting is carried out, and a throwing sheet B is obtained by rapid hardening and throwing; finally, the rest Al ingot and the weighed Ni are placed at 1560 +/-20 ℃ for vacuum melting, and a throwing sheet C is obtained through rapid hardening and throwing; carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C;
s4, coarse crushing and airflow milling: and placing the flail piece A, the flail piece B and the flail piece C subjected to vacuum annealing treatment into a mortar, crushing by using a punch, sieving the coarse crushed powder obtained by crushing, preferably sieving the coarse crushed powder obtained by crushing through a 50-mesh sieve every 2-3 minutes to obtain alloy coarse powder, and then finely crushing by using an air mill to prepare powder. The preferable airflow milling powder process comprises the following steps: the sorting rotation speed is 1600-2000r/min, the pressure of the grinding chamber is 610-630KPa, and the weight of the grinding chamber is 4-6Kg.
S5, mixed powder pressing: adding aluminum stearate into the prepared airflow milled powder, continuously mixing uniformly, and performing compression molding to obtain a compression blank with a corresponding shape; wherein, 0.4 to 0.6 weight percent of aluminum stearate is preferably added into the milled powder of the gas making flow and the mixture is continuously mixed for 15 to 30min. For example, 0.4wt%,0.45wt%,0.5wt%,0.55wt%,0.6wt%. The pressure applied in the press molding is preferably 20 to 30t.
S6, sintering, heat treatment and tempering, finish machining and inspection: putting the pressed blank into a vacuum sintering furnace, performing vacuum sintering, cooling and discharging to obtain a sintered blank; carrying out magnetic field heat treatment on the sintered blank, and then carrying out four-stage tempering to obtain a semi-finished blank; and (3) finely grinding the semi-finished product blank, removing oxide skin flaws on the surface, cleaning, and obtaining the desired product high-performance powder sintered alnico magnetic material after the inspection is qualified.
The invention cancels the use of simple substance powder, selects the alloy with low cost and stable property, changes the process flow of the existing powder sintering, simplifies the procedure, eliminates the processes with high energy consumption and high safety evaluation requirements such as ammonia decomposition and the like, and prepares the high-performance powder sintering alnico alloy material by preparing three alloy raw materials and preparing powder by an airflow mill. The invention fully considers the hardness and melting point characteristics of each component alloy, improves the hardness by adjusting the composition and granularity of the alloy and annealing, adapts alloy components with approximate melting points and moderate hardness, is beneficial to forming a plurality of coarse grains in the processes of rapid powder preparation and sintering, and improves the magnetic property.
According to the invention, the annealing treatment process in the steps S2 and S3 comprises the following steps: heating to 1000-1060 ℃ at room temperature at a heating rate of 60-100 ℃/h, preserving heat for 3-4 h, then cooling to 150 ℃ at a rate of 20-60 ℃/h, discharging, and cooling to room temperature. The invention controls the speed, temperature and time of the annealing treatment process in the above range, mainly considering the influence of temperature on internal phase transformation and grain boundary improvement, if the temperature rising/reducing speed is too fast, the transformation of austenite into pearlite is not thorough, and the internal phase transformation is not uniform; on the other hand, if the temperature rise rate is too slow, the Al element tends to volatilize seriously and to be oxidized.
For example, the annealing process in step S2 is: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a rate of 20 ℃/h, discharging and cooling to room temperature; or heating to 1020 ℃ at room temperature at the heating rate of 80 ℃/h, preserving heat for 3h, then cooling to 150 ℃ at the temperature of 40 ℃/h, discharging, and cooling to room temperature; or heating to 1040 ℃ at room temperature at the heating rate of 100 ℃/h, preserving heat for 2h, then cooling to 150 ℃ at the temperature of 60 ℃/h, discharging, and cooling to room temperature.
Preferably, the Nb content in the NbFe alloy is 65wt%, and the purity of other elementary substance alloys is more than or equal to 99.5%.
Preferably, the rapid hardening melt-spun conditions are as follows: the rotation speed of the copper roller is 50 +/-10 r/min, and the thickness of the flail is 0.20-0.35 mm.
According to the invention, the composition ratio of the throwing piece A, the throwing piece B and the throwing piece C is dependent on the alloy, and the alloy can not be smoothly crushed into fine powder finally, and the temperature intervals among different components are close to each other in the sintering process, so that a uniform and compact whole is formed. Through the element proportion of the throwing piece A, the throwing piece B and the throwing piece C, for example, co and Ni with higher hardness are properly matched with other 'flexible' metal elements in a certain proportion to achieve the aim of smoothly crushing and preparing powder, and the phenomena of difficulty in densification and the like, wherein the phenomena that single/multiple metals form a free state and are volatilized to form loss, the final components of the magnet material deviate from the original design or are unevenly sintered, and the melting temperature difference among different components cannot be too large in the sintering process are considered. Therefore, by comprehensive consideration, the invention controls the mass ratio of different elements within the range, and is beneficial to adjusting the sintering temperature and time to obtain the sintered compact magnetic steel.
Preferably, the powder obtained by the jet mill has a particle size D 50 ：20～22μm，D 90 /D 10 5.6 to 6.2; for example, the particle diameter D of the powder obtained by jet milling 50 ：20μm，D 90 /D 10 =5.8; particle diameter D of the powder 50 ：21μm，D 90 /D 10 =6.0; particle diameter D of the powder 50 ：22μm，D 90 /D 10 =6.2. The particle size of the powder prepared by the jet milling mainly influences the difficulty of compression molding, and if the particle size is too large or too small, a pressed blank is easy to crack, difficult to mold or excessively high in pressure required by pressing.
Preferably, a nitrogen pipe is arranged on a pressure head of the punching machine, the nitrogen pipe introduces nitrogen into the mortar during punching, and a cooling device is arranged around the mortar.
Preferably, the step of vacuum sintering the pressed blank in step S6 includes: heating to 450-500 ℃ at room temperature at the heating rate of 3-5 ℃/min, and keeping the temperature for 1-2 hours; then heating to 800-900 ℃ and preserving heat for 1-2 hours, and continuing heating to 1290-1320 ℃ and preserving heat for 0.2-0.5 hours; then continuously heating to 1330-1350 ℃, preserving the heat for 4.5-6 hours, and cooling to the room temperature along with the furnace.
For example, heating to 500 ℃ at a heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing heating to 1300 ℃ and preserving heat for 0.2h, then continuing heating to 1340 ℃, preserving heat for 6h, and finally cooling to room temperature along with the furnace; or heating to 450 ℃ at the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃ and preserving heat for 2h, continuing heating to 1290 ℃ and preserving heat for 0.3h, then continuing heating to 1330 ℃, preserving heat for 5h, and finally cooling to room temperature along with the furnace; or heating to 450 deg.C at a heating rate of 3 deg.C/min, maintaining for 2h, heating to 800 deg.C, maintaining for 2h, heating to 1320 deg.C, maintaining for 0.3h, heating to 1350 deg.C, maintaining for 4.5h, and cooling to room temperature.
Preferably, the step of performing magnetic field heat treatment on the sintered blank comprises the following steps: pretreating the sintered blank in a box-type resistance furnace at 800-900 ℃ for 30-50 min; then transferring the blank to a high-temperature furnace at 1260-1280 ℃, and carrying out solid melting heat treatment for 20-40 min; taking out the blank, air-cooling for 1-5 minutes, transferring the blank into a magnetic field, and carrying out isothermal heat treatment at 750-850 ℃ for 20-30 min; taking out and cooling to room temperature.
In a preferred embodiment of the invention, the method further comprises the step of carrying out four-stage tempering on the sintered blank after the magnetic field heat treatment: firstly preserving heat for 3-4 hours at 630-650 ℃, then preserving heat for 6-8 hours at 600-620 ℃, cooling to 570-590 ℃, preserving heat for 8-10 hours, continuously cooling to 540-560 ℃, preserving heat for 8-10 hours, and finally cooling along with the furnace to obtain a semi-finished product blank.
For example, firstly preserving heat at 640 ℃ for 4h, preserving heat at 610 ℃ for 8h, continuously preserving heat at 580 ℃ for 8h, preserving heat at 550 ℃ for 10h, and finally cooling along with a furnace; or firstly preserving the heat at 635 ℃ for 3h, preserving the heat at 620 ℃ for 7h, continuously preserving the heat at 585 ℃ for 9h, preserving the heat at 555 ℃ for 9h, and finally cooling along with the furnace; or firstly preserving the heat at 630 ℃ for 3h, preserving the heat at 600 ℃ for 7h, continuously preserving the heat at 570 ℃ for 9h, preserving the heat at 540 ℃ for 9h, and finally cooling along with the furnace.
The invention fully utilizes the characteristic that the alloy is more stable than a simple substance, particularly the Al alloy, improves the stability of the Al content, cancels hydrogen reduction and reduces the production cost. And the composition and proportion of the alloys are adjusted, and the annealing process is assisted to improve the alloy, so that the limitation that the conventional aluminum-nickel-cobalt alloy is difficult to crush and cannot be prepared into powder is broken through. The subsequent powder preparation by airflow milling improves the particle size range and distribution of each alloy composition, improves the magnetic property, and provides a rapid and low-cost manufacturing process for sintering alnico powder.
The technical scheme of the invention is further specifically explained by the following specific embodiments:
the NbFe alloy used in the following examples has an Nb content of 65wt% and a purity of other elementary alloys of not less than 99.5%.
Example 1
1) Weighing a certain mass part of metal simple substance and alloy, wherein the mass part of the metal simple substance and the alloy is 100 parts, and the mass part of the Al ingot is as follows: 7 parts, 12.8 parts of Ni sheet, 3 parts of Cu sheet, and Co sheet: 37.3 parts; 1 part of NbFe; ti:6 parts of (1); the balance of Fe rods.
2) Putting the weighed Cu, nbFe, ti and Fe rods and 22 parts of Co into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to 1600 ℃, and casting after refining the materials, wherein the vacuum rapid hardening melt-spun process comprises the following steps: the rotation speed of a copper roller is 50 +/-10 r/min, a quick-setting flail A with the thickness of 0.20mm is obtained, and then vacuum annealing treatment is carried out. The vacuum annealing treatment process comprises the following steps: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a temperature of 20 ℃/h, discharging, and cooling to room temperature.
3) The remaining Co, as Co flakes: the ratio of Al ingot =3 is 1560 +/-20 ℃, vacuum melting is carried out, and a throwing sheet B is obtained by rapid hardening and throwing; finally, putting the rest Al ingot and the Ni sheet into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and throwing to obtain throwing sheets C; and (3) carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C, wherein the vacuum rapid hardening and strip throwing process is the same as the step 2).
4) Putting the annealed throwing sheet A, throwing sheet B and throwing sheet C into a mortar, crushing by a punching machine, and arranging a nitrogen pipe on a pressure head of the punching machineIntroducing nitrogen into a mortar through a nitrogen pipe in the stamping process, arranging a cooling device around the mortar, sieving coarse crushed powder obtained by crushing through a 50-mesh sieve every 2-3 minutes to obtain alloy coarse powder, and then finely crushing the alloy coarse powder through an airflow mill to prepare powder with a powder particle size D 50 ：20μm，D 90 /D 10 ＝5.8。
5) Adding 0.5wt% of aluminum stearate into the fine powder prepared by the jet mill, continuously mixing for 15 minutes, and performing compression molding to obtain a blank pressing product.
6) And (3) putting the blank pressed product into a vacuum sintering furnace, heating to 500 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing heating to 1300 ℃ and preserving heat for 0.2h, then continuing heating to 1340 ℃ and preserving heat for 6h, and finally cooling to room temperature along with the furnace.
7) And (3) performing magnetic field heat treatment on the obtained product, firstly, pre-treating the blank in a box-type resistance furnace at 800 ℃ for 50min, then transferring the blank to a high-temperature furnace at 1260 ℃, and performing solid melting heat treatment for 40min. And then, taking out the blank, air-cooling for 2 minutes, and transferring to a magnetic field for isothermal heat treatment at 750 ℃ for 30min. Taking out and cooling to room temperature, and then carrying out four-stage tempering treatment: sequentially preserving the heat at 640 ℃ for 4h, preserving the heat at 610 ℃ for 8h, preserving the heat at 580 ℃ for 8h, preserving the heat at 550 ℃ for 10h, and finally cooling along with the furnace.
8) And (3) finely grinding the semi-finished product blank to remove flaws such as oxide skin on the surface, cleaning, and obtaining the high-performance powder sintered alnico magnetic steel after the inspection is qualified.
The component table of the high-performance powder sintered alnico magnetic steel is Al 7 Ni 12.8 Co 37.3 Cu 3 Nb 0.64 Ti 6 Fe Surplus 。
Example 2
1) Weighing a certain mass part of metal simple substances and alloys, wherein the mass part of the metal simple substances and the alloys is 100 parts, and the mass part of the metal simple substances and the alloys is as follows: 6.5 parts, 13 parts of Ni sheet, 3.5 parts of Cu sheet, co sheet: 36.5 parts of; nbFe:1 part; ti:6 parts of (1); the balance of Fe rods.
2) Putting the weighed Cu, nbFe, ti and Fe rods and 22 parts of Co into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to 1620 ℃, and casting after refining the materials, wherein the vacuum rapid hardening melt-spun process comprises the following steps: the rotation speed of the copper roller is 50 +/-10 r/min, and the quick-setting melt-spun piece A with the thickness of 0.20mm is obtained, and then the vacuum annealing treatment is carried out. The vacuum annealing treatment process comprises the following steps: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a temperature of 20 ℃/h, discharging, and cooling to room temperature.
3) Taking the weighed Al ingot and the rest Co sheets, and mixing the weighed Al ingot and the rest Co sheets in a Co sheet: the ratio of Al ingot =3 is 1560 +/-20 ℃, vacuum melting is carried out, and a throwing sheet B is obtained by rapid hardening and throwing; finally, putting the rest Al ingot and the weighed Ni sheets into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and spinning to obtain a spinning sheet C; carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C; the vacuum rapid hardening melt spinning process is the same as the steps.
4) Putting the throwing sheet A, the throwing sheet B and the throwing sheet C into a mortar, crushing by a punching machine, arranging a nitrogen pipe on a pressure head of the punching machine, introducing nitrogen into the mortar by the nitrogen pipe in the punching process, arranging a cooling device around the mortar, sieving the coarse crushing powder obtained by crushing by a 50-mesh sieve at intervals of 2-3 minutes to obtain alloy coarse powder, and then finely crushing by an air mill to prepare powder with a powder particle diameter D 50 ：21μm，D 90 /D 10 ＝6.0。
5) Adding 0.5% aluminum stearate into the fine powder prepared by the jet mill, and continuously mixing for 20min. Pressing and forming to obtain a blank pressed product;
6) Putting the pressed blank into a vacuum sintering furnace, heating to 450 ℃ at the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃ and preserving heat for 2h, continuing heating to 1290 ℃ and preserving heat for 0.3h, then continuing heating to 1330 ℃, preserving heat for 5h, and finally cooling to room temperature along with the furnace;
7) And (3) performing magnetic field heat treatment on the product obtained in the step (6), firstly, placing the blank in a box type resistance furnace at 850 ℃ for pretreatment for 40min, then transferring the blank to a high-temperature furnace at 1280 ℃, and performing solid melting heat treatment for 30min. And then, taking out the blank, air-cooling for 3 minutes, and transferring to a magnetic field to perform isothermal 770 ℃ heat treatment for 20min. Taking out, cooling to room temperature, performing four-stage tempering treatment, wherein the process comprises the steps of insulating at 635 ℃ for 3h, insulating at 620 ℃ for 7h, insulating at 585 ℃ for 9h, insulating at 555 ℃ for 9h, and finally cooling along with the furnace.
8) And (3) finely grinding the semi-finished blank to remove surface scale and other defects, and cleaning to obtain the high-performance powder sintered alnico magnetic steel.
The component table of the high-performance powder sintered alnico magnetic steel is Al 6.5 Ni 13 Co 36.5 Cu 3.5 Nb 0.64 Ti 6 Fe Surplus 。
Example 3
1) Weighing a certain mass part of metal simple substance and alloy, wherein the mass part of the metal simple substance and the alloy is 100 parts, and the mass part of the Al ingot is as follows: 6.0 parts, 13.5 parts of Ni sheet, 3.0 parts of Cu sheet, and the weight ratio of Co sheet: 37 parts of; nbFe:1.08 parts of a modifier; ti:6.5 parts; the balance of Fe rods.
2) Putting the weighed Cu, nbFe, ti and Fe rods and 24 parts of Co into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to be 1600 +/-20 ℃, and casting after refining the materials, wherein the vacuum rapid hardening melt-spun process comprises the following steps: the rotation speed of the copper roller is 50 +/-10 r/min, and the quick-setting melt-spun piece A with the thickness of 0.20mm is obtained, and then the vacuum annealing treatment is carried out. The vacuum annealing treatment process comprises the following steps: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a temperature of 20 ℃/h, discharging, and cooling to room temperature.
3) Taking the weighed Al ingot and the rest Co sheets, and mixing the weighed Al ingot and the rest Co sheets in a Co sheet: the ratio of Al ingot =3 is 1560 +/-20 ℃, vacuum melting is carried out, and a throwing sheet B is obtained by rapid hardening and throwing; finally, putting the rest Al ingot and the weighed Ni sheets into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and throwing to obtain throwing sheets C; carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C; the vacuum rapid hardening melt spinning process is the same as the steps.
4) Putting the throwing sheet A, the throwing sheet B and the throwing sheet C into a mortar, crushing by a punching machine, arranging a nitrogen pipe on a pressure head of the punching machine, introducing nitrogen into the mortar by the nitrogen pipe in the punching process, arranging a cooling device around the mortar, sieving the coarse crushing powder obtained by crushing by a 50-mesh sieve at intervals of 2-3 minutes to obtain alloy coarse powder, and then finely crushing by an air mill to prepare powder with a powder particle diameter D 50 ：22μm，D 90 /D 10 ＝6.2。
5) Adding 0.5wt% of aluminum stearate into the fine powder prepared by the jet mill, and continuously mixing for 30min. And pressing and forming to obtain a blank pressed product.
6) And (3) putting the pressed blank into a vacuum sintering furnace, heating to 450 ℃ at the heating rate of 3 ℃/min, preserving heat for 2h, then heating to 800 ℃ and preserving heat for 2h, continuing heating to 1320 ℃ and preserving heat for 0.3h, then continuing heating to 1350 ℃, preserving heat for 4.5h, and finally cooling to room temperature along with the furnace.
7) And (3) performing magnetic field heat treatment on the product obtained in the step 6), firstly, placing the blank in a box-type resistance furnace at 900 ℃ for pretreatment for 50min, then transferring the blank to a high-temperature furnace at 1280 ℃, and performing solid melting heat treatment for 25min. And then, taking out the blank, air-cooling for 5 minutes, and transferring to a magnetic field to perform isothermal 790 ℃ heat treatment for 15min. Taking out, cooling to room temperature, performing four-stage tempering treatment, wherein the process comprises the steps of maintaining at 630 ℃ for 3h, maintaining at 600 ℃ for 7h, maintaining at 570 ℃ for 9h and maintaining at 540 ℃ for 9h, and finally cooling along with the furnace.
8) And (3) finely grinding the semi-finished product blank to remove flaws such as oxide skin on the surface, cleaning, and obtaining the high-performance powder sintered alnico magnetic steel after the inspection is qualified.
The component table of the high-performance powder sintered alnico magnetic steel is Al 6.0 Ni 13.5 Co 37 Cu 3.5 Nb 0.7 Ti 6.5 Fe Surplus 。
Example 4
1) Weighing a certain mass part of metal simple substances and alloys, wherein the mass part of the metal simple substances and the alloys is 100 parts, and the mass part of the metal simple substances and the alloys is as follows: 7 parts, 12.8 parts of Ni sheet, 3 parts of Cu sheet, and Co sheet: 37.3 parts; 1 part of NbFe; ti:6 parts of (1); the balance of Fe rods.
2) Putting the weighed Cu, nbFe, ti and Fe rods and 22 parts of Co into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to 1600 ℃, and casting after refining the materials, wherein the vacuum rapid hardening melt-spun process comprises the following steps: the rotation speed of the copper roller is 50 +/-10 r/min, and the rapid hardening and throwing piece A with the thickness of 0.20mm is obtained and then is subjected to vacuum annealing treatment. The vacuum annealing treatment process comprises the following steps: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a temperature of 20 ℃/h, discharging, and cooling to room temperature.
3) The weighed Al ingot and the remaining Co were mixed in a Co flake: the ratio of Al ingot =3 is 1560 +/-20 ℃, vacuum melting is carried out, and a throwing sheet B is obtained by rapid hardening and throwing; finally, putting the rest Al ingot and the weighed Ni sheets into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and throwing to obtain throwing sheets C; and (3) carrying out vacuum annealing treatment on the swing piece B and the swing piece C, wherein the vacuum rapid hardening and belt swinging process is the same as that in the step 2).
4) Putting the annealed flappers A, B and C into a mortar, crushing by a punch, arranging a nitrogen pipe on a pressure head of the punch, introducing nitrogen into the mortar by the nitrogen pipe in the punching process, arranging a cooling device around the mortar, sieving coarse crushing powder obtained by crushing by a 50-mesh sieve at intervals of 2-3 minutes to obtain alloy coarse powder, and then finely crushing by an air mill to prepare powder with a powder particle diameter D 50 ：15μm，D 90 /D 10 ＝5.5。
5) Adding 0.5wt% of aluminum stearate into the fine powder prepared by the jet mill, continuously mixing for 15 minutes, and performing compression molding to obtain a blank pressing product.
6) And (3) putting the blank pressed product into a vacuum sintering furnace, heating to 500 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing heating to 1300 ℃ and preserving heat for 0.2h, then continuing heating to 1340 ℃ and preserving heat for 6h, and finally cooling to room temperature along with the furnace.
7) And (3) performing magnetic field heat treatment on the obtained product, firstly, placing the blank in a box-type resistance furnace at 800 ℃ for pretreatment for 50min, then transferring the blank to a high-temperature furnace at 1260 ℃, and performing solid melting heat treatment for 40min. And then, taking out the blank, air-cooling for 2 minutes, and transferring to a magnetic field for isothermal heat treatment at 750 ℃ for 30min. Taking out and cooling to room temperature, and then carrying out four-stage tempering treatment: sequentially preserving the heat at 640 ℃ for 4h, preserving the heat at 610 ℃ for 8h, preserving the heat at 580 ℃ for 8h, preserving the heat at 550 ℃ for 10h, and finally cooling along with the furnace.
8) And (3) finely grinding the semi-finished blank to remove surface scale and other defects, cleaning, and obtaining the high-performance powder sintered alnico magnetic steel after the inspection is qualified.
Example 5
1) Weighing metal simple substances and alloy, wherein the weight of an Al ingot is as follows according to 100 parts: 7 parts, 12.8 parts of Ni sheet, 3 parts of Cu sheet, and Co sheet: 37.3 parts; 1 part of NbFe; ti:6 parts of (1); the balance of Fe rods.
2) Putting the Cu, nbFe, ti, fe rods and 22 parts of Co into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to be 1600 ℃, and casting after refining the materials, wherein the vacuum rapid hardening melt-spun process comprises the following steps: the rotation speed of the copper roller is 50 +/-10 r/min, and the rapid hardening and throwing piece A with the thickness of 0.20mm is obtained and then is subjected to vacuum annealing treatment. The vacuum annealing treatment process comprises the following steps: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a temperature of 20 ℃/h, discharging, and cooling to room temperature.
3) Mixing the rest Co, co sheet: the Al ingot =3, the proportion of 1 is 1560 +/-20 ℃, and a throwing sheet B is obtained by rapid hardening and throwing; finally, putting the rest Al ingot and the weighed Ni sheets into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and spinning to obtain a spinning sheet C; and (3) carrying out vacuum annealing treatment on the swing piece B and the swing piece C, wherein the vacuum rapid hardening and belt swinging process is the same as that in the step 2).
4) Putting the annealed flappers A, B and C into a mortar, crushing by a punch, arranging a nitrogen pipe on a pressure head of the punch, introducing nitrogen into the mortar by the nitrogen pipe in the punching process, arranging a cooling device around the mortar, sieving the coarse crushed powder obtained by crushing by a 50-mesh sieve at intervals of 2-3 minutes to obtain alloy coarse powder, and then finely crushing by an air mill to prepare powder with a powder particle diameter D 50 ：26μm，D 90 /D 10 ＝5.2。
5) Adding 0.5wt% of aluminum stearate into the fine powder prepared by the jet mill, continuously mixing for 15 minutes, and performing compression molding to obtain a blank pressing product.
6) And (3) putting the blank pressed product into a vacuum sintering furnace, heating to 500 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing to heat to 1300 ℃ and preserving heat for 0.2h, then continuing to heat to 1340 ℃ and preserving heat for 6h, and finally cooling to room temperature along with the furnace.
7) And (3) performing magnetic field heat treatment on the obtained product, firstly, placing the blank in a box-type resistance furnace at 800 ℃ for pretreatment for 50min, then transferring the blank to a high-temperature furnace at 1260 ℃, and performing solid melting heat treatment for 40min. And then, taking out the blank, air-cooling for 2 minutes, and transferring to a magnetic field for isothermal heat treatment at 750 ℃ for 30min. Taking out and cooling to room temperature, and then carrying out four-stage tempering treatment: sequentially preserving the heat at 640 ℃ for 4h, preserving the heat at 610 ℃ for 8h, preserving the heat at 580 ℃ for 8h, preserving the heat at 550 ℃ for 10h, and finally cooling along with the furnace.
8) And (3) finely grinding the semi-finished product blank to remove flaws such as oxide skin on the surface, cleaning, and obtaining the high-performance powder sintered alnico magnetic steel after the inspection is qualified.
Fig. 1, 2 and 3 are diagrams of formed blanks prepared in example 1, example 4 and example 5 respectively, and it can be seen from the diagrams that when the grain size of the alloy powder prepared by jet milling is smaller, the formed blank is easy to generate cracks, which affects the performance of the product; on the contrary, when the alloy powder prepared by the jet milling has larger grain diameter, the product is difficult to mold and demold, burrs are easily generated around the blank, and the processing of subsequent products is difficult. When the grain diameter D of the alloy powder 50 ：20～22μm，D 90 /D 10 And when the density is in the range of 5.6-6.2, the prepared formed blank is complete in shape and uniform in density, and a foundation is laid for obtaining qualified products subsequently.
Comparative example 1
1) According to the composition of the embodiment 1, coAl alloy powder, nbFe alloy powder and TiFe alloy powder which are based on the reference of the content ratio of Al, nb and Ti are respectively weighed according to the prior traditional manufacturing process, wherein the content ratio of Co in the CoAl alloy is 75%, the content ratio of Nb in the NbFe alloy is 65%, the content ratio of Ti in the TiFe alloy is 30%, and the CoAl alloy powder, the NbFe alloy powder and the TiFe alloy powder are all sieved by a 200-mesh sieve according to the particle size requirement.
2) In addition, according to the components of the simple substance alloy in the embodiment 1, the simple substance alloy powder, the Ni powder, the Co powder, the Cu powder and the Fe powder are weighed in corresponding parts by mass. Wherein the Ni powder is sieved by a 300-mesh sieve, the Co/Cu/Fe powder is sieved by a 200-mesh sieve, and the four elementary substance powders are placed in a vacuum reduction furnace and are reduced at the high temperature of 500 ℃ for 150min in the hydrogen atmosphere. After cooling to room temperature, sieving the reduced powder through a 80-mesh standard sieve;
3) Mixing the reduced powder and the alloy powder, adding 0.5wt% of aluminum stearate, continuously mixing for 15min, and performing compression molding to obtain a blank pressing product.
4) And (3) putting the pressed blank into a vacuum sintering furnace, heating to 500 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then heating to 900 ℃ and preserving heat for 1h, continuing heating to 1300 ℃ and preserving heat for 0.2h, then continuing heating to 1340 ℃ and preserving heat for 6h, and finally cooling to room temperature along with the furnace.
5) And (5) performing magnetic field heat treatment on the product obtained in the step 4), firstly, pre-treating the blank in a box-type resistance furnace at 800 ℃ for 50min, then transferring the blank to a high-temperature furnace at 1260 ℃, and performing solid melting heat treatment for 40min. And then, taking out the blank, air-cooling for 2 minutes, and transferring to a magnetic field for isothermal heat treatment at 750 ℃ for 30min. Taking out and cooling to room temperature, tempering treatment is carried out, the process comprises the steps of preserving heat at 640 ℃ for 4h, preserving heat at 610 ℃ for 8h, preserving heat at 580 ℃ for 8h, preserving heat at 550 ℃ for 10h, and finally cooling along with a furnace.
6) And (4) finely grinding the semi-finished product blank, removing flaws such as oxide skin on the surface, cleaning, and obtaining a desired product after the inspection is qualified.
The remanence (KGs), coercive force and magnetic energy product of the magnets prepared in examples 1 to 5 and comparative example 1 were measured by using an AMT-4 permanent magnet characteristic automatic measuring instrument, and the results are shown in table 1.
TABLE 1 results of magnet performance test
Figure GDA0003819437400000171
As can be seen from the data in table 1, the remanence (KGs), coercive force, magnetic energy product performance of the magnets prepared in examples 1 to 5 are superior to those of the magnet prepared in comparative example 1, and the remanence (KGs), coercive force, magnetic energy product, and the like of the magnets prepared in examples 4 and 5 are slightly inferior to those of examples 1 to 3, but are also significantly superior to those of the magnet prepared in comparative example 1, because the alloy powder prepared in the jet milling step has a small or large particle size.
Therefore, according to the method for manufacturing the powder sintering alnico material by three kinds of alloy smelting and airflow milling, the prepared sintering alnico material has more excellent magnetic performance than that prepared by the traditional method by blending alloy components and optimizing the particle size, has very important significance for improving the application range of the sintering alnico material and expanding the market occupation ratio, opens up a new path for preparing the powder sintering alnico, effectively improves the production cost of the sintering alnico, optimizes the preparation process and expands the application range of the sintering alnico.
The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and the scope of protection of the present invention for preparing sintered alnico by three kinds of alloy melting and jet milling should be subject to the claims.

Claims (16)

1. A preparation method of a high-performance powder sintered alnico magnetic material is characterized by comprising the following steps:
s1, weighing a certain mass part of simple substances and alloys, wherein the mass part of the simple substances and the alloys is 100, and the mass part of the simple substances and the alloys is as follows: 5-7 parts of Ni sheet, 12-14 parts of Cu sheet, 3-4 parts of Co sheet: 36-38 parts of NbFe:1-1.5 parts of Ti:5.5-7.0 parts; the balance of Fe rods; the Nb content in the NbFe alloy is 65wt%;
s2, putting the weighed metal simple substances Cu, ti and Fe rods and 22-25 parts of Co and alloy NbFe into a vacuum rapid hardening melt-spun furnace, vacuumizing, heating, controlling the smelting temperature to be 1600 +/-20 ℃, casting the refined material to obtain a rapid hardening melt-spun piece A, and then carrying out vacuum annealing treatment;
s3, mixing the weighed Al ingot and the rest Co slices in a Co slice mode: putting the Al ingot = 1 in 1560 +/-20 ℃ of weight ratio, and carrying out vacuum melting, and quickly solidifying and throwing to obtain a throwing sheet B; finally, putting the rest Al ingot and the weighed Ni into 1560 +/-20 ℃ for vacuum melting, and quickly solidifying and throwing to obtain throwing pieces C; carrying out vacuum annealing treatment on the throwing piece B and the throwing piece C;
s4, placing the annealed flappers A, B and C into a mortar, crushing by using a punch, sieving coarse crushing powder obtained by crushing to obtain alloy coarse powder, and then finely crushing by using an airflow mill to prepare powder;
s5, adding 0.5wt% of aluminum stearate into the prepared airflow milled powder, continuously mixing uniformly, and performing compression molding to obtain a compression blank with a corresponding shape;
s6, sintering the pressed blank in vacuum, cooling and discharging to obtain a sintered blank; carrying out magnetic field heat treatment on the sintered blank, and then carrying out four-stage tempering to obtain a semi-finished blank; finely grinding the semi-finished product blank to remove oxide skin flaws on the surface to obtain a high-performance powder sintered alnico magnetic material;
the annealing treatment process in the steps S2 and S3 comprises the following steps: heating to 1000-1060 ℃ at room temperature at a heating rate of 60-100 ℃/h, preserving heat for 3-4 h, then cooling to 150 ℃ at a rate of 20-60 ℃/h, discharging, and cooling to room temperature;
the particle diameter of the powder prepared by the jet mill is D 50 ：20～22μm，D 90 /D 10 ＝5.6～6.2。
2. The method according to claim 1, wherein the annealing process of step S2 comprises: heating to 1000 ℃ at room temperature at a heating rate of 60 ℃/h, preserving heat for 4h, then cooling to 150 ℃ at a rate of 20 ℃/h, discharging and cooling to room temperature; or alternatively
Heating to 1020 ℃ at room temperature at a heating rate of 80 ℃/h, preserving heat for 3h, then cooling to 150 ℃ at a rate of 40 ℃/h, discharging, and cooling to room temperature; or alternatively
Heating to 1040 ℃ at room temperature at a heating rate of 100 ℃/h, preserving heat for 2h, then cooling to 150 ℃ at a heating rate of 60 ℃/h, discharging, and cooling to room temperature.
3. The method of claim 1, wherein the rapid setting melt-spinning conditions are: the rotating speed of the copper roller is 50 +/-10 r/min, and the thickness of the flaked sheet is 0.20-0.35 mm.
4. The method of claim 1, wherein the elemental alloy has a purity of 99.5% or more.
5. The method of claim 1, wherein the jet mill flour process: the sorting rotation speed is 1600-2000r/min, the pressure of the grinding chamber is 610-630KPa, and the weight of the grinding chamber is 4-6Kg.
6. The method of claim 1, wherein the jet mill produces a powder having a particle size D 50 ：20μm，D 90 /D 10 =5.8; particle diameter D of powder 50 ：21μm，D 90 /D 10 =6.0; particle diameter D of powder 50 ：22μm，D 90 /D 10 ＝6.2。
7. The method according to claim 1, wherein a nitrogen gas pipe is provided on a ram of the press machine, the nitrogen gas pipe introduces nitrogen gas into the mortar during the pressing, and a cooling device is provided around the mortar.
8. The method of claim 1, wherein 0.4 to 0.6 wt.% of aluminum stearate is added to the resulting jet mill powder in step S5.
9. The method of claim 1, wherein the aluminum stearate is added to the prepared jet mill powder in step S5 in an amount of 0.4wt%,0.45wt%,0.5wt%,0.55wt%, or 0.6wt%.
10. The method according to claim 1, wherein the pressure applied in the press molding is 20 to 30t.
11. The method of claim 1, wherein the coarsely crushed powder obtained by crushing is passed through a 50-mesh sieve every 2 to 3 minutes.
12. The method of claim 1, wherein the step of vacuum sintering the pressed blank in step S6 comprises: heating to 450-500 ℃ at room temperature at the heating rate of 3-5 ℃/min, and keeping the temperature for 1-2 hours; then heating to 800-900 ℃ and preserving heat for 1-2 hours, and continuing heating to 1290-1320 ℃ and preserving heat for 0.2-0.5 hours; then continuously heating to 1330-1350 ℃, preserving the heat for 4.5-6 hours, and cooling to room temperature along with the furnace.
13. The preparation method according to claim 1, wherein the mixture is heated to 500 ℃ at a heating rate of 5 ℃/min, kept warm for 1 hour, then heated to 900 ℃ and kept warm for 1 hour, then heated to 1300 ℃ and kept warm for 0.2 hour, then heated to 1340 ℃ and kept warm for 6 hours, and finally cooled to room temperature along with the furnace; or
Heating to 450 ℃ at the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃ and preserving heat for 2h, continuing heating to 1290 ℃ and preserving heat for 0.3h, then continuing heating to 1330 ℃, preserving heat for 5h, and finally cooling to room temperature along with the furnace; or
Heating to 450 ℃ at the heating rate of 3 ℃/min, preserving heat for 2h, then heating to 800 ℃ and preserving heat for 2h, continuing heating to 1320 ℃ and preserving heat for 0.3h, then continuing heating to 1350 ℃, preserving heat for 4.5h, and finally cooling to room temperature along with the furnace.
14. The method of claim 1, wherein the step of magnetic field heat treating the sintered blank comprises: pretreating the sintered blank in a box-type resistance furnace at 800-900 ℃ for 30-50 min; then transferring the blank to a high-temperature furnace at 1260-1280 ℃, and carrying out solid melting heat treatment for 20-40 min; taking out the blank, air-cooling for 1-5 minutes, transferring the blank into a magnetic field, and carrying out isothermal heat treatment at 750-850 ℃ for 20-30 min; taking out and cooling to room temperature.
15. The method of claim 1, further comprising the step of four-stage tempering the sintered blank after the magnetic field heat treatment: firstly preserving heat for 3-4 hours at 630-650 ℃, then preserving heat for 6-8 hours at 600-620 ℃, cooling to 570-590 ℃, preserving heat for 8-10 hours, continuously cooling to 540-560 ℃, preserving heat for 8-10 hours, and finally cooling along with the furnace to obtain a semi-finished product blank.
16. The preparation method of claim 15, wherein the temperature is maintained at 640 ℃ for 4h,610 ℃ for 8h,580 ℃ for 8h,550 ℃ for 10h, and finally furnace cooling is carried out; or firstly preserving the heat at 635 ℃ for 3h, preserving the heat at 620 ℃ for 7h, continuously preserving the heat at 585 ℃ for 9h, preserving the heat at 555 ℃ for 9h, and finally cooling along with the furnace; or firstly preserving the heat at 630 ℃ for 3h, preserving the heat at 600 ℃ for 7h, continuously preserving the heat at 570 ℃ for 9h, preserving the heat at 540 ℃ for 9h, and finally cooling along with the furnace.
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JPH07272912A (en) * 1994-04-01 1995-10-20 Daido Steel Co Ltd Permanent magnet powder and bonded magnet using the same
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JPH10280011A (en) * 1997-04-04 1998-10-20 Pacific Ind Co Ltd Production of alnico alloy powder
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