KR20050066465A - The soft magnetic fe-based nano-alloy powder having superior to br/bs and the method there of - Google Patents

Abstract

The present invention relates to a soft magnetic Fe-based nanoalloy powder having an excellent angular ratio and a method of manufacturing the same, and more specifically, to (a) a Fe-based amorphous alloy powder, by milling the powder thickness to diameter ratio of 2 to 20. (B) heat-treating the shape-controlled Fe-based amorphous alloy powder to form a nanocrystalline alloy powder having an average grain size of 5 to 50 nm, and (c) weakly acidifying the nanocrystalline alloy powder. After dipping into a solution and etching, grinding to prepare a nano alloy powder having an average powder particle diameter of 50 nm or less, and (d) post-treating the prepared nano alloy powder to remove internal stress and improve magnetic properties. Characterized in that comprises a.

According to the present invention, the coercive force is low, and the nano alloy powder having the improved square ratio and the saturation magnetic flux density is greatly improved, thereby replacing the expensive Co-based amorphous alloy ribbon applied to the anti-theft tag. It is possible to supply raw materials at a low price, and the soft magnetic properties are greatly improved as compared to conventional alloy powders, and thus it is effective to be applied to various fields.

Description

Soft magnetic Fe-based nanoalloy powder with excellent square ratio and its manufacturing method {The Soft Magnetic Fe-based Nano-alloy Powder Having Superior to Br / Bs and The Method There of}

The present invention relates to a soft magnetic Fe-based nanoalloy powder having an excellent angular ratio and a method of manufacturing the same, and more particularly, to a Fe-based amorphous alloy powder having excellent soft magnetic properties, shape control, nanocrystallization, heat treatment, etching treatment, milling treatment, And a soft magnetic Fe-based nanoalloy powder having excellent angular ratio that can be applied as a raw material to an anti-theft tag at a low price by lowering the coercive force, which is a magnetic property of the alloy powder, and greatly improving the angular ratio.

The material that is applied as a material such as a tag for preventing theft is a Co-based amorphous alloy ribbon mainly manufactured by rapid solidification method, the Co-based alloy alloy ribbon is a high cost of the raw materials and when the tag is manufactured according to the ribbon There was a problem that many work processes such as cutting of ribbon and use of adhesive are required.

Therefore, in order to solve the above problems, a method of applying an alloy powder instead of manufacturing a ribbon has been introduced, but when applying an alloy powder of several μm or more as a tag material, the coercive force of the alloy powder is very high and the angular ratio is 5%. As it is very low as below, a large capacity of the sensor and a deterioration of the detection function are caused, and there is still a problem that there is a limitation in applying it as a tag material, and also in the manufacture of an alloy powder by applying a grinding method of a general alloy powder. It takes a very long time, and thus there is a problem in that the soft magnetic properties are greatly reduced because a large amount of impurities are contained in the prepared alloy powder.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to shape-control, heat treatment, nanocrystallization, etching treatment, milling the Fe-based amorphous alloy powder is a soft magnetic material excellent in soft magnetic properties By lowering the coercive force, which is a magnetic property of the alloy powder, and greatly improving the square ratio by treatment and post-treatment, it is possible to replace expensive Co-based amorphous alloy ribbons applied to anti-theft tags at low cost, and compared with conventional alloy powders. The soft magnetic properties are greatly improved to provide a method for producing a soft magnetic Fe-based nanoalloy powder having a wide range of applications.

In addition, another object of the present invention is to provide a soft magnetic Fe-based nano alloy powder having a small coercive force produced by the above production method and having greatly improved square ratio and saturation magnetic flux density.

Method for producing a soft magnetic Fe-based nanoalloy powder having excellent square ratio according to the present invention for achieving the above object is (a) Fe-based amorphous alloy powder by milling the thickness: diameter ratio of 2 to 20 (B) heat-treating the shape-controlled Fe-based amorphous alloy powder to prepare a nanocrystalline alloy powder having an average grain size of 5 to 50 nm, and (c) the nanocrystalline alloy powder. Immersing in a weak acid solution and etching, followed by grinding to prepare a nanoalloy powder having an average powder particle diameter of 50 nm or less, and (d) post-treatment of the prepared nanoalloy powder to remove internal stress and improve magnetic properties. Characterized in that comprises a step.

And, the average grain size of the Fe-based amorphous alloy powder according to the invention is characterized in that less than 20㎛.

In addition, the heat treatment of step (b) according to the present invention is characterized in that it is carried out at a temperature of 5 ~ 150 ℃ higher than the initiation temperature of the crystallization of the Fe-based amorphous alloy powder in the magnetic field or 1,000 ~ 10,000Gauss magnetic field.

The weak acid solution according to the present invention is characterized in that it comprises any one of 0, 5 to 10% hydrochloric acid solution, sulfuric acid solution, nitric acid solution.

Post-treatment of step (d) according to the invention is characterized in that it is carried out at 300 ~ 600 ℃ under reducing gas.

In addition, the soft magnetic Fe-based nanoalloy powder having an excellent angular ratio according to the present invention is subjected to a shape control treatment of the Fe-based amorphous alloy powder, followed by heat treatment to prepare a nanocrystalline alloy powder, and the prepared nanocrystalline alloy powder is crushed after etching. And it is prepared by post-treatment, the coercive force is 20 Oe or less, the angular ratio is 10% or more and the saturation magnetic flux density is characterized by more than 100emu / g.

Hereinafter, the present invention will be described in detail.

In the soft magnetic Fe-based nanoalloy powder having excellent square ratio according to the present invention and a method for manufacturing the same, the Fe-based amorphous alloy powder used as a raw material powder may be prepared by mechanical alloying, quench solidification, high pressure water spraying, or the like. In this invention, it is preferable to manufacture by the high pressure water spraying method.

The high pressure water spraying method is a method for preparing an amorphous alloy powder, which has been invented and filed by the present applicant (Korean Patent Application No. 2000-0022312). The molten metal is crushed by a high pressure water spray of 30 MPa or more and then quenched to form an amorphous alloy. It is characterized by the production of high quality amorphous alloy powders with various particle sizes through the change of the spraying conditions while making the powder simplified and manufacturing time shorter than the conventional water spraying method.

On the other hand, the Fe-based amorphous alloy powder produced by the high pressure water spraying method has a particle size distribution of 0.5 to 100 µm, and an average powder particle diameter of 20 µm or less, preferably as small as possible.

The Fe-based amorphous alloy powder having an average powder particle diameter of 20 μm or less is shape controlled through a ball milling process. The shape control is to control the shape of the alloy powder by using a chromium coated ball or iron ball, to determine the strength and weight of the ball to perform the process to avoid agglomeration of powder during the process as much as possible and the fracture (fracture) of the powder The shape of the powder should be controlled by performing the process for a time period to avoid it.

Through the shape control, the aspect ratio, which is the ratio of thickness to diameter of the alloy powder, is preferably in the range of 2 to 20. When the aspect ratio is 2 or less, anisotropic treatment becomes difficult, and in the case of 20 or more, shape control is required. The problem is that the time to be a long time.

The shape-controlled Fe-based amorphous alloy powder is subjected to heat treatment for about 0.5 to 3 hours at a temperature higher than the crystallization start temperature of the powder and a magnetic or magnetic field, thereby obtaining a nanocrystalline alloy powder having an average grain size of 5 to 50 nm.

If the temperature of the heat treatment is too high, the grain size may be coarsened and intermetallic compounds may be produced. On the contrary, if the temperature of the heat treatment is too low, sufficient nanocrystal grains may not be produced. It is preferable to carry out at. In addition, the heat treatment under the magnetic field is to improve the square ratio by providing magnetic anisotropy, the higher the magnetic field strength, the greater the effect of improving the square ratio, but the cost of equipment, such as equipment costs can increase, the strength of the magnetic field is 1,000 to 10,000 Gauss is preferred.

The nanocrystalline alloy powder prepared by the heat treatment is dipped in an acid solution such as hydrochloric acid, nitric acid and sulfuric acid for 0.5 to 10% for 0.5 to 5 hours, followed by etching and drying. The etching process is a method of corroding and erasing a metal surface. Corrosion is a surface corrosion in which the entire surface is uniformly eroded according to its shape, a gap corrosion in the form of corrosion occurring in a gap, or a specific element is deposited at grain boundaries or grain boundaries. In the present invention, a specific alloy element is deficient, and thus, a relatively large local corrosion can be classified into a grain boundary corrosion, which is a form in which a relatively large local corrosion progresses along the grain boundary. In the present invention, a large local corrosion is formed along the grain boundary of the nanocrystalline alloy powder. It is preferable to perform an advanced grain boundary etching process.

After the etching treatment, the nanocrystalline alloy powder is pulverized using a ball milling apparatus to prepare a nanoalloy powder having an average powder particle diameter of 50 nm or less. The alloy powder subjected to the grain boundary etching is more easily pulverized during the milling process than the powder before the etching. And the grinding time through the milling process can be changed according to the ball milling device and the grinding conditions, it is preferable to perform the milling treatment for 1 to 10 hours using the planetary ball milling device.

The nanoalloy powder prepared by the above process uses a reducing gas to remove internal stress and improve magnetic properties, and is subjected to post-heat treatment at a temperature of 300 to 600 ° C.

Hereinafter, a preferred embodiment of the method for preparing a soft magnetic Fe-based nanoalloy powder having excellent square ratio according to the present invention will be described in detail.

Example 1

1kg of amorphous alloy powder (average particle diameter: 5㎛, particle size distribution: 0.5 ~ 100㎛) of Fe _83.5 Si _13.5 B ₉ Nb ₃ Cu ₁ composition prepared by high pressure water injection method, planetary ball mill (Ball / powder ratio = 6/1) After milling for 5hr, the aspect ratio is controlled to 5/1, and then heat-treated under 5,000Gauss magnetic field for 30 minutes under Ar gas atmosphere of 550 ℃ higher than the initiation temperature of crystallization. The average size of the particles was about 15 nm, then etched in 5% hydrochloric acid solution for 1hr, dried and milled for 5hr using a planetary ball mill (Ball / powder ratio = 6/1) to obtain an average powder particle size. It was prepared to be 20nm. The prepared nanopowders were subjected to stress relief heat treatment at 500 ° C. for 30 minutes under a reducing component atmosphere of H 2 gas.

Here, the crystallization start temperature of the amorphous powder is measured by heating at a heating rate of 2 ℃ / min using DTA (Differential Temperature Analysis), the average size of the grain and powder X-ray diffraction (XRD) and particle size analyzer The saturation magnetic flux density (Bs), coercive force, and square ratio (Br / Bs) are measured under an external magnetic field of 5,000 Gauss using VSM (Vibrating Sample Magnetometer).

Example 2

Fe ₈₀ Al ₄ B ₁₀ Zr ₅ Cu ₁ amorphous alloy powder (average particle diameter: 3㎛, particle size distribution: 0.5 ~ 60㎛) prepared by water-jet method and heat treatment at 470 ℃ higher 5 ℃ than crystallization start temperature The same procedure as in Example 1 was followed.

Example 3

Fe ₇₉ Al ₃ B ₁₂ Nb ₅ Cu ₁ amorphous alloy powder (average particle size: 3㎛, particle size distribution: 0.5 ~ 60㎛) prepared by water-jet method and heat treatment at 450 ℃ higher than the initiation temperature of crystallization The same procedure as in Example 1 was followed.

Example 4

Fe ₈₃ Nb ₇ B ₉ Cu ₁ amorphous alloy powder (average particle diameter: 10㎛, particle size distribution: 0.5 ~ 100㎛) manufactured by the water-jet method, except for heat treatment at 550 ℃ higher than the crystallization start temperature 50 ℃ It carried out similarly to Example 1.

Example 5

The etching was carried out in the same manner as in Example 1 except that the etching time was 5 hours using a 1% hydrochloric acid solution.

Example 6

The same procedure as in Example 1 was conducted except that a 5% nitric acid solution was used.

Example 7

The same procedure as in Example 1 was conducted except that a 5% sulfuric acid solution was used.

Example 8

The shape-controlled powder was carried out in the same manner as in Example 1 except that the powder was heat-treated under no magnetic field.

Comparative Example 1

It carried out similarly to Example 1 except not having performed the shape control process process.

Comparative Example 2

It carried out similarly to Example 1 except having omitted the etching process.

Condition number Characteristics of Raw Powder Manufacture conditions Product Specifications Alloy used (at%)  Average particle diameter Crystallization Start Temperature Aspect Ratio (width / height) Crystallization Heat Treatment Temperature Average nanocrystal grain size Etching Solution Grinding time Average particle size of powder Saturated magnetic flux density (Bs, emu / g) Coercive force (Hc, Oe) Square ratio (Br / Bs,%) Example 1 Fe _83.5 Si _13.5 B ₉ Nb ₃ Cu ₁ 5 μm 540 ℃ 5/1 550 ℃ 15 nm 5% hydrochloric acid solution 5hr 20 nm 130 5 25 Example 2 Fe ₈₀ Al ₄ B ₁₀ Zr ₅ Cu ₁ 2 μm 465 ℃ 4/1 470 ℃ 10 nm " " 15 nm 150 8 20 Example 3 Fe ₇₉ Al ₃ B ₁₂ Nb ₅ Cu ₁ 3 μm 435 ℃ 8/1 450 ℃ 10 nm " " 15 nm 145 10 23 Example 4 Fe ₈₃ Nb ₇ B ₉ Cu ₁ 10 μm 500 ℃ 12/1 550 ℃ 10 nm " " 15 nm 162 12 25 Example 5 Fe _83.5 Si _13.5 B ₉ Nb ₃ Cu ₁ 5 μm 540 ℃ 5/1 550 ℃ 15 nm 1% hydrochloric acid solution " 20 nm 130 5 20 Example 6 " " " " " " 5% nitric acid solution " 20 nm 130 5 23 Example 7 " " " " " " 5% sulfuric acid solution " 20 nm " 5 22 Example 8 " " " " " " 5% hydrochloric acid solution 10hr 20 nm " 5 11 Comparative Example 1 " " " 1/1 " " " 5hr 30 nm " 10 One Comparative Example 2 " " " " " " - 5hr 250 nm " 30 5

Referring to Table 1, the Fe-based amorphous alloy powder capable of nanocrystallization in the case of all the examples can be produced with an average powder particle size of several tens of nm or less by the manufacturing process of the present invention, accordingly all coercive force is 20 Oe or less While significantly lowering, the average magnetic flux density is improved to 100 emu / g or more, and as the aspect ratio is adjusted by the shape control process, the angular ratio is rapidly increased to several tens of percent. In addition, it is noted that the equivalent configuration modified or changed by those skilled in the art in order to carry out the same purpose of the present invention does not depart from the scope of the technical idea of the present invention described in the claims. Should be.

Therefore, modifications or changes in equivalent configurations by those skilled in the art will be constrained by the technical scope of the present invention as set forth in the claims.

As described above, the soft magnetic Fe-based nanoalloy powder having excellent square ratio according to the present invention and a manufacturing method thereof are characterized in that the Fe-based amorphous alloy powder, which is a soft magnetic material having excellent soft magnetic properties, is subjected to shape control, heat treatment, nanocrystallization, etching treatment, Milling and post-treatment have the effect of producing nanoalloy powder with low coercivity, which is a magnetic property of the alloy powder, and greatly improving the square ratio and saturation magnetic flux density. By substituting Co-based amorphous alloy ribbon, it is possible to supply raw materials at a low price, and the soft magnetic properties are greatly improved as compared to conventional alloy powders, and thus it is effective to be applied to various fields.

Claims (6)

(a) milling the Fe-based amorphous alloy powder to shape-control the thickness to diameter ratio of 2 to 20; (b) heat-treating the shape-controlled Fe-based amorphous alloy powder to produce a nanocrystalline alloy powder having an average grain size of 5 to 50 nm; (c) immersing the nanocrystalline alloy powder in a weak acid solution, followed by etching, and grinding to prepare a nanoalloy powder having an average powder particle diameter of 50 nm or less; And (d) a method for producing a soft magnetic Fe-based nanoalloy powder having excellent square ratio, characterized in that it comprises the step of post-treating the prepared nano alloy powder to improve the internal stress and magnetic properties. The method of claim 1, The method for producing a soft magnetic Fe-based nanoalloy powder having excellent angular ratio, characterized in that the average grain size of the Fe-based amorphous alloy powder is 20㎛ or less. The method of claim 1, The heat treatment in the step (b) is performed at a temperature of 5 to 150 ℃ higher than the initiation temperature of the crystallization of the Fe-based amorphous alloy powder in a magnetic field or a magnetic field of 1,000 ~ 10,000Gauss soft magnetic Fe-based nanoparticles having excellent angular ratio Method for producing alloy powder. The method of claim 1, The weak acid solution is a method of producing a soft magnetic Fe-based nanoalloy powder having excellent square ratio, characterized in that it comprises any one of 0, 5 to 10% hydrochloric acid solution, sulfuric acid solution, nitric acid solution. The method of claim 1, The post-treatment of the step (d) is carried out at 300 ~ 600 ℃ under reducing gas, the method of producing a soft magnetic Fe-based nano-alloy powder having excellent square ratio. The Fe-based amorphous alloy powder is subjected to shape control treatment, followed by heat treatment to prepare a nanocrystalline alloy powder, and the prepared nanocrystalline alloy powder is prepared by etching, pulverizing and post-treatment, having a coercivity of 20 Oe or less and a square ratio of 10%. The soft magnetic Fe-based nanoalloy powder having excellent square ratio, characterized in that the saturation magnetic flux density is 100 emu / g or more.