KR20190091149A - Fe-Cr-Co-X system Alloy Powder for Counterfeit Prevention, and Method for Manufacturing The Same - Google Patents

Abstract

The present invention relates to magnetic alloy powder for forgery prevention and manufacturing method thereof, wherein Fe-Cr-Co-X system alloy powder is manufactured by a gas spray method or a gas and water spray hybrid method. X of the alloy powder comprises at least one or two elements of Ni, Al, Cu, Mn, Si, B, C, W, Mo, Ti, Nb, and V. The alloy powder for forgery prevention has a spherical particle with a diameter of 1-30 μm. An average aspect ratio of the powder particle is 1 to 3, and average oxygen concentration of the particle is 2000 ppm or less. Moreover, a magnetic change in accordance with an environmental change is small so that the magnetic alloy powder can be used as magnetic ink for forgery prevention.

Description

Fe-Cr-Co-X system alloy powder for counterfeit prevention, and method for manufacturing the same}

Recently, anti-counterfeiting and security materials are printed with fine characters structured with various codes for anti-counterfeiting and security of banknotes, checks, passports, gift certificates, cards and high-quality household goods, security paper, etc. Various security materials using color conversion and magnetism have been applied and used.

    The present invention relates to a magnetic alloy powder that can be used for magnetic ink (magnetic ink) that can be recognized by Magnetic Ink Character Recognition (MICR), which is one of the anti-counterfeiting and security material materials, and a method of manufacturing the same. will be.

The atomization process, which is well known as one of the methods of preparing powders of pure metals, alloys, ceramics, and composites thereof, is classified into a gas spray method, a water spray method, and a mixed spray method according to the type of cooling medium.

The gas spraying method uses inert gas (N ₂ , Ar, He) or air (air), so it is possible to produce high quality powder because of less oxidation and impurity mixing problems in powder manufacturing, but it is fine in alloy powder because of low cooling effect Segregation is not possible to obtain a homogeneous alloy powder, there is a problem that the production cost is increased because the price of the gas used is relatively high.

The water atomization process uses relatively inexpensive water (H ₂ 0) instead of gas or air as the main refrigerant, so it has a large cooling effect, which is advantageous for the production of fine powder due to the small amount of fine segregation. Although there is a point, it is difficult to apply when the shape and oxidation of the powder to be produced is a problem.

The mixed spray method is a manufacturing method using a mixture of gas (N ₂ , Ar, He), air, and water as an appropriate ratio as a cooling medium, and has been applied as a manufacturing method considering the advantages and disadvantages of the above-described gas spraying method or water spraying method.

However, in order to produce the amorphous alloy powder by the above-described gas spraying method, the spraying medium (N ₂ , Ar, He, air, and mixtures thereof) is sprayed at a high pressure of 30 kgf / cm ² (about 29.42 bar) or higher to generate powder. While the first cooling, but then scattered in a large chamber is cooled at a relatively low rate, it is difficult to prevent the micro segregation of the alloying components and not obtain a microstructure, it is more difficult to produce amorphous alloy powder.

On the other hand, the water spraying method, which has better cooling effect than the gas spraying method, uses relatively inexpensive water, which can reduce the cost of powder products, and can reduce fine segregation due to the large cooling effect, but the total amount of Fe elements exceeds 85 at% It is known that it is difficult to produce amorphous alloy powder of 20 µm or more because the amorphous forming ability is drastically lowered (a cooling rate of 10 ⁵ K / sec or more is required).

The magnetic alloy for MICR, which is usually considered as a forgery prevention and security material, basically has a saturation magnetization (Ms) range of 70 to 90 emu / g, and a residual magnetization (Mr) range of 20 to 39 emu / g. The coercive force (Hc) is not only required for magnetic properties in the range of 250 to 500 Oe, but also for maintaining stability against various environmental changes (temperature and humidity).

First, in the case of the magnetic properties that can be used as the magnetic powder for MICR, the semi-hard magnetic materials of soft magnetic materials and hard magnetic materials developed to date are Suitable.

Existing patent applications for the magnetic particles and the manufacturing method thereof (Korean Patent Application Nos. 10-2010-0138765, 10-2010-0139125) and Magnetic Pigments (Korean Application No. 10-2013-7017454) The present invention aims to provide a novel Fe-Cr-Co-X alloy powder having magnetic properties suitable for anti-counterfeiting.

Korea Patent Registration No. 10-1308953 Korea Patent Registration No. 10-1339099 Korea Patent Registration No. 10-1339099 Korean Patent Registration No. 10-1208918 Korea Patent Registration No. 10-1339070 Korean Patent Registration No. 10-1339080 Korea Patent Registration No. 10-1208909 Korean Patent Registration No. 10-1341150 Korean Patent Application No. 10-2013-7017454 Korean Patent Application No. 10-2002-7014102 Korean Patent Application No. 10-2013-0163976 Korean Patent Application No. 10-2012-7001696 Korea Patent Registration No. 10-1016922

The present invention has been made in view of the above-mentioned conventional matters, and improves the cooling effect during the production of alloy powder, and produces a small density of spherical alloy powder, as well as a small density of satellite powder (satellites) to produce a molding density of powder products It is an object of the present invention to provide an alloy powder and a method for producing the same, which improves properties by increasing (micro density, green density).

The present invention is a Fe-Cr-Co-X-based alloy powder prepared by a gas spray method or a gas water spray hybrid method (Gas & water hybrid), wherein X of the alloy powder is Ni, Al, Cu, Mn, Si, B It provides a forgery-resistant magnetic alloy powder, characterized in that it comprises one or two or more elements of C, W, Mo, Ti, Nb, V.

In one embodiment, the alloy powder may be spherical particles having a diameter of 1 ~ 30 ㎛.

In one embodiment, the alloy powder may be an average of the aspect ratio of 1 to 3.

In one embodiment, the alloy powder may have an average oxygen concentration of 2000 ppm or less.

In one embodiment, the Fe-Cr-Co-X-based alloy powder is 30 mass% ≤Fe≤80 mass%, 5 mass% ≤Cr≤25 mass%, 3 mass% ≤Co≤30 mass%, 0 mass% ≤ X ≤ 30 mass%.

In addition, the present invention comprises the steps of (i) mixing and dissolving Fe powder, Cr powder, Co powder and X powder as starting materials, to form a spherical magnet alloy powder by gas spraying or gas water dispersion method; And (ii) maintaining the spherical alloy powder at a temperature in the range of 500-750 ° C. for 30 minutes to 2 hours, and then aging the spherical alloy powder to room temperature at a cooling rate of 2.5 ° C./min. It provides a method for producing a powder.

The present invention is a Fe-Cr-Co-X-based alloy powder, wherein the anti-counterfeiting alloy powder is spherical particles having a diameter of 1 to 30 ㎛, the average aspect ratio of the powder particles is 1 to 3, the average oxygen concentration is 2000ppm or less It has a particle characteristic and has a characteristic of little magnetic change due to environmental change, and thus can be used as a magnetic ink for preventing forgery.

In addition, the alloy powder of the present invention was prepared by the gas and water yarn hybrid method, heat treatment and furnace cooling, there is little microsegregation and satellite powder and the molding density was increased to improve the characteristics of the alloy powder.

1 is a SEM photograph of the Fe-Cr-Co-X-based alloy powder according to an embodiment of the present invention.
2 is a graph showing the saturation magnetization value of Fe-Cr-Co-X-based alloy powder according to an embodiment of the present invention.
Figure 3 is a graph showing the residual magnetization value of the Fe-Cr-Co-X-based alloy powder according to an embodiment of the present invention.
Figure 4 is a graph showing the coercive force value of the Fe-Cr-Co-X-based alloy powder according to an embodiment of the present invention.

The present invention is a Fe-Cr-Co-X-based alloy powder prepared by a gas spray method or a gas water spray hybrid method, wherein X of the alloy powder is Ni, Al, Cu, Mn, Si, B, C, W, Mo It provides a spherical anti-counterfeiting magnetic alloy powder comprising one or two or more of Ti, Nb, and V elements.

The magnetic alloy for MICR, which is usually considered as a forgery prevention and security material, basically has a saturation magnetization (Ms) range of 70 to 90 emu / g, and a residual magnetization (Mr) range of 20 to 39 emu / g. The coercive force (Hc) is not only required for magnetic properties in the range of 250 to 500 Oe, but also for maintaining stability against various environmental changes (temperature and humidity).

First, in the case of the magnetic properties that can be used as the magnetic powder for MICR, the semi-hard magnetic materials of soft magnetic materials and hard magnetic materials developed to date are Suitable.

In one embodiment, the alloy powder may be spherical particles having a diameter of 1 ~ 30 ㎛.

In one embodiment, the alloy powder may be an average of the aspect ratio of 1 to 3.

In one embodiment, the alloy powder may have an average oxygen concentration of 2000 ppm or less.

In one embodiment, the Fe-Cr-Co-X-based alloy powder is one kind wherein X in the composition formula is selected from Ni, Al, Cu, Mn, Si, B, C, W, Mo, Ti, Nb, V Or 2 or more kinds of elements, and 30 mass% ≤ Fe ≤ 80 mass%, 5 mass% ≤ Cr ≤ 25 mass%, 3 mass% ≤ Co ≤ 30 mass%, 0 mass% ≤ X ≤ 30 mass% Can be.

In one embodiment, the alloy powder is represented by Fe-Cr-Co-Si-Ti-Ni-Al-Cu-based material, 40 mass% ≤Fe≤60 mass%, 5 mass% ≤Cr≤10 mass%, 10 mass% ≤ Co ≤ 30 mass%, 0 mass% ≤ Si ≤ 0.40 mass%, 1 mass% ≤ Ti ≤ 5.0 mass%, 5 mass% ≤ Ni ≤ 20 mass%, 1 mass% ≤ Ai ≤ 10 mass%, It may be 1 mass% ≦ Cu ≦ 3 mass%.

In addition, the present invention comprises the steps of (i) mixing and dissolving Fe powder, Cr powder, Co powder and X powder as starting materials, to form a spherical magnet alloy powder by gas spraying or gas water dispersion method; And (ii) the spherical alloy powder is held at a temperature in the range of 500 to 750 ° C., preferably at 700 ° C. for 30 minutes to 2 hours, preferably 1 hour, and then at room temperature at a cooling rate of 2.5 ° C./min. It provides a method of producing anti-counterfeiting magnetic alloy powder, including the step of aging treatment.

In one embodiment, the alloy powder in step (ii) may be furnace cooled after heat treatment.

In one embodiment, the anti-counterfeiting magnetic alloy powder may be used as a magnetic ink. Magnetic ink refers to magnetic ink, and when a printed item is placed in a reader, magnetic ink is sensed and arrangement is automatically performed. It is used for checking checks and tickets.

In one embodiment, the magnetic ink may further include an polymerization inhibitor, an antioxidant, an antifoaming agent, a surfactant, or an adhesion enhancer as an adjuvant.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to the specific embodiments, it should be understood that it includes all changes, equivalents, and substitutes included in the spirit and scope of the present invention, and may be modified in various other forms. However, the scope of the present invention is not limited to the following examples.

<Examples>

Composition of Synthetic Powder of the Invention

The elements of Fe, Cr, Co, Si, Ti, Ni, Al, and Cu having the compositions shown in Table 1 below were used as raw materials for the synthetic powders of Examples 1 to 9. As a comparative example, powders without addition of cobalt and without heat treatment were also prepared, and their properties were compared with those of the above examples.

Table 1 shows the composition of the anti-counterfeiting alloy powder of the present invention, its heat treatment conditions and magnetic properties. The composition of the alloy powder is expressed in weight percent.

division
Fe
Cr
Co
Si
Ti
Ni
Al
Cu
Heat treatment condition Magnetic properties Ms
(emu / g) Mr
(emu / g) Hc
(Oe) Example 1 54.65 10.0 14.0 0.3 3.0 10.0 5.0 2.0 700 degrees Celsius * 1h → furnace cooling 109.7 10.76 156.6 Example 2 54.65 10.0 12.0 0.3 3.0 10.0 5.0 2.0 700 degrees Celsius * 1h → furnace cooling 71.54 10.71 215.4 Example 3 54.65 10.0 12.0 0.3 3.0 8.0 5.0 2.0 700 degrees Celsius * 1h → furnace cooling 64.64 11.51 239.8 Example 4 53.65 10.0 14.0 0.3 3.0 8.0 5.0 2.0 700 degrees Celsius * 1h → furnace cooling 65.68 10.93 221.8 Example 5 46.65 5.0 16.0 0.3 3.0 17.0 5.0 2.0 700 degrees Celsius * 1h → furnace cooling 102.9 23.17 441.2 Example 6 48.65 5.0 20.0 0.3 3.0 17.0 3.0 2.0 700 degrees Celsius * 1h → furnace cooling 36.32 2.393 90.50 Example 7 46.65 5.0 20.0 0.3 3.0 17.0 3.0 2.0 700 degrees Celsius * 1h → furnace cooling 96.39 13.23 215.0 Example 8 46.65 5.0 24.0 0.3 3.0 15.0 3.0 2.0 700 degrees Celsius * 1h → furnace cooling 44.93 3.215 118.5 Example 9 42.65 5.0 24.0 0.3 3.0 15.0 3.0 2.0 700 degrees Celsius * 1h → furnace cooling 90.25 21.16 409.9 Comparative example 44.7 - 24 0.32 4.24 17.6 6.6 2.5 - 139.0 38.52 538.8

Example  Preparation of 1 to 9 Synthetic Powders

Synthesis powder of Examples 1 to 9, (i) preparing the spherical magnet alloy powder by the gas spray method or the gas water spray hybrid method by mixing and dissolving the elements having the above composition as a starting material; (Ii) the spherical alloy powder was prepared by a manufacturing method comprising maintaining the spherical alloy powder at a temperature in the range of 700 ° C. for 1 hour and then aging to room temperature at a cooling rate of 2.5 ° C./min.

The apparatus for producing the anti-counterfeiting magnetic alloy powder by the gas water-spray hybrid method of step (iii) has the following structure: An amorphous alloy raw material having the composition shown in Table 1 is charged therein, and the amorphous alloy raw material is melted. Crucible dissolving with; An orifice installed below the crucible to discharge the molten metal; A gas injection nozzle provided at a lower end of the orifice and cooling the molten metal with a semi-liquid alloy powder by injecting a refrigerant gas toward the molten metal to be discharged; A chamber positioned below the gas injection nozzle to receive and disperse and cool the semi-liquid alloy powder to produce amorphous alloy powder; An impeller rotatably installed at a lower end of the chamber and guiding the produced amorphous alloy powder into a recovery container; And rotating means for applying a driving force to rotate the impeller, wherein the impeller rotates with a driving force applied from the rotating means.

In step (ii), the synthetic powder was cooled to the furnace after heat treatment.

Magnetic Characterization of Synthetic Powders of the Invention

The magnetic alloy for MICR, which is usually considered as a forgery prevention and security material, basically has a saturation magnetization (Ms) range of 70 to 90 emu / g, and a residual magnetization (Mr) range of 20 to 39 emu / g. The coercive force (Hc) is not only required for magnetic properties in the range of 250 to 500 Oe, but also for maintaining stability against various environmental changes (temperature and humidity).

In Example 9 of Table 1, Ms is 90.25 emu / g, Mr is 21.16 emu / g, and Hc is 409.9 Oe, which satisfies the magnetic range. In the comparative example without heat treatment without addition of cobalt, magnetic properties were generally stronger than those of the examples.

Claims (6)

Fe-Cr-Co-X-based alloy powder prepared by a gas spray method or a gas water spray hybrid method (Gas & water hybrid), wherein X of the alloy powder is Ni, Al, Cu, Mn, Si, B, C, An anti-counterfeiting magnet alloy powder comprising one or two or more elements of W, Mo, Ti, Nb, and V. The anti-counterfeiting magnetic alloy powder according to claim 1, wherein the alloy powder is spherical particles having a diameter of 1 to 30 µm. The anti-counterfeiting magnetic alloy powder according to claim 1, wherein the alloy powder has an aspect ratio of 1 to 3 on average. The anti-counterfeiting magnetic alloy powder according to claim 1, wherein the alloy powder has an average oxygen concentration of 2000 ppm or less. The method of claim 1,
An anti-counterfeiting magnetic alloy powder, characterized in that 30 mass% ≤ Fe ≤ 80 mass%, 5 mass% ≤ Cr ≤ 25 mass%, 3 mass% ≤ Co ≤ 30 mass%, 0 mass% ≤ X ≤ 30 mass%. (Iii) mixing and dissolving Fe powder, Cr powder, Co powder and X powder as starting materials to produce spherical magnet alloy powder by gas spraying or gas water dispersion; And
(Ii) holding the spherical alloy powder at a temperature in the range of 500-750 ° C. for 30 minutes to 2 hours, and then aging to a room temperature at a cooling rate of 2.5 ° C./min. The manufacturing method of the anti-counterfeiting magnetic alloy powder in any one of Claim 5.

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