KR100340489B1 - Surface treatment method of magnetic metal powder using stearic acid - Google Patents

Surface treatment method of magnetic metal powder using stearic acid Download PDF

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KR100340489B1
KR100340489B1 KR1019950048676A KR19950048676A KR100340489B1 KR 100340489 B1 KR100340489 B1 KR 100340489B1 KR 1019950048676 A KR1019950048676 A KR 1019950048676A KR 19950048676 A KR19950048676 A KR 19950048676A KR 100340489 B1 KR100340489 B1 KR 100340489B1
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metal powder
magnetic metal
stearic acid
surface treatment
magnetic
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KR970043268A (en
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김병원
변태봉
손진군
김대영
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주식회사 포스코
재단법인 포항산업과학연구원
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/712—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the surface treatment or coating of magnetic particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal

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  • Magnetic Record Carriers (AREA)
  • Powder Metallurgy (AREA)
  • Hard Magnetic Materials (AREA)

Abstract

PURPOSE: A method of surface treating magnetic metal powder with stearic acid is provided to improve oxidation resistance of magnetic metal powder suitable for use in magnetic recording media. CONSTITUTION: In a surface treatment method of magnetic metal powder on the surface of which organic film is formed to improve corrosion resistance, the method is characterized in that magnetic metal powder is dipped in an organic solvent in which based on the total weight of magnetic metal powder, 0.5 to 10.0 wt.% of stearic acid is dissolved to form organic film on the surface of magnetic metal powder, and then organic solvent is completely evaporated, wherein the organic solvent is selected from alcohol, toluene and benzene.

Description

스테아릭산을 이용한 자성금속 분말의 표면처리방법Surface treatment method of magnetic metal powder using stearic acid

본 발명은 오디오, 비디오등의 자기기록매체에 사용되는 자성금속분말의 표면처리 방법에 관한 것으로, 보다 상세하게는. 자성금속분말의 표면을 스테아릭산(stearicacia CH3(CH2)16COOH)을 이용하여 처리하므로서 자성금속 분말의 내산화성을 향상시키도록된 표면처리 방법에 관한 것이다.The present invention relates to a surface treatment method of magnetic metal powder used in magnetic recording media such as audio and video, and more particularly. The surface of the magnetic metal powder is treated with stearic acid (stearicacia CH 3 (CH 2 ) 16 COOH) by the surface treatment method to improve the oxidation resistance of the magnetic metal powder.

일반적으로 고성능 자기기록 매체용 자성체로서 철 또는 철을 다량 포함하는 침상의 자성금속 분말(장단축의 비가 5:1-10:1, 장축이 0.01-0.25㎛)이 사용되고 있다. 이러한 자성금속분말은 자기특성이 산화물 자성체 보다 우수하지만 금속분말이기 때문에 화학적으로 불안정한 단점이 있다. 즉, 공기증에서 산화되기 쉽고 경우에 따라서는 발화 위험이 있다. 따라서 경시적으로 자기특성이 저하되고 심하면 분말이 자기특성을 잃어버리게 되는 문제점이 있다.Generally, a needle-like magnetic metal powder containing a large amount of iron or iron (a ratio of 5: 1-10: 1 in long axis and 0.01-0.25 µm in long axis) is used as a magnetic material for a high performance magnetic recording medium. Such magnetic metal powders have superior magnetic properties than oxide magnetic materials but have chemically unstable disadvantages because they are metal powders. That is, it is easy to oxidize in the air vapor and in some cases there is a risk of fire. Therefore, there is a problem in that the magnetic properties are degraded over time and if the powder loses the magnetic properties over time.

이와같이 자성금속분말 표면이 산화되어 경시변화에 따른 자기특성 저하의 문제점을 해결하기 위하여 자성금속분말의 표면에 무기물 피막을 형성시켜 분말의 산화를 방지하는 방법이 제안되었으나, 이 방법은 대기환경 분위기에서는 H2O 때문에 바람직하지 않아 유기물 피복을 형성시키는 방법이 제안 되었다.In order to solve the problem of deterioration of magnetic properties due to oxidization of the surface of magnetic metal powder, a method of preventing the oxidation of powder by forming an inorganic film on the surface of magnetic metal powder has been proposed. Due to H 2 O, a method of forming an organic coating has been proposed.

이러한 유기물 피복의 형성방법으로는 주로 기상 혹은 액상에서 자성금속분말을 서서히 산화하여 입자표면에 치밀한 산화막을 형성시키는 방법을 사용하고 있는데, 이러한 자성금속분말의 내산화성을 향상 시키기 위한 표면처리 방법으로는 종래 많은 제안이 행해졌으며, 그중 대표적인 것으로는 다음과 같은 것을 예로 들수 있다.As a method of forming the organic material coating, a method of forming a dense oxide film on the surface of a particle by gradually oxidizing a magnetic metal powder in a gaseous phase or a liquid phase is used as a surface treatment method for improving oxidation resistance of the magnetic metal powder. Many proposals have been made in the past, and representative examples thereof are as follows.

자성금속분말의 표면을 결합제로 개질하는 방법(일본국 특개평 1-230702), 자성금속분말을 수증기를 함유한 불활성 가스로 처리한 다음 산소를 함유한 가스를 이용해서 입자표면을 산화시켜 부동태 산화물 피막을 형성하는 방법(일본국 특개평1-241801), 자성금속분말 표면을 유기산동염의 분해 잔사물로 처리하는 방법(일본국 특개평 1-27442), 안식향산 유도체 화합물로 자성금속분말의 표면을 처리하는 방법(일본국 특개평 1-281706), 과산화 벤조일을 이용한 자성금속분말의 표면처리법(일본국 특개평 1-281704)및 산무수물로 자성금속분말의 표면을 처리하는 방법(일본국 특개평 1-281705)들이 바로 그것이다.A method of modifying the surface of a magnetic metal powder with a binder (Japanese Patent Laid-Open No. 1-230702), treating the magnetic metal powder with an inert gas containing water vapor and then oxidizing the particle surface using an oxygen-containing gas to passivate the oxide. A method of forming a film (Japanese Patent Laid-Open Publication No. 1-241801), a method of treating the surface of a magnetic metal powder with decomposed residues of organic acid copper salt (Japanese Patent Laid-Open Publication No. 1-27442), and a surface of the magnetic metal powder with a benzoic acid derivative compound. Method of treatment (Japanese Patent Laid-Open Publication No. 1-281706), surface treatment method of magnetic metal powder using benzoyl peroxide (Japanese Patent Laid-Open Publication No. 1-281704), and method of treating the surface of the magnetic metal powder with an acid anhydride (Japanese Patent Laid-Open Publication No. 1-281705).

본 발명자는 상기한 종래방법들에서와는 다른 유기물을 사용하여 자성금속분말의 표면에 내산화성이 우수한 유기물 피막을 형성시키고자 연구와 실험을 행한결과, 스테아릭산을 사용하여 자성금속분말의 표면처리를 행하면 내산화성을 향상시킬수 있다는 사실에 착안하여 본발명을 제안하게 된 것이다.The present inventors have conducted research and experiments to form an organic film having excellent oxidation resistance on the surface of the magnetic metal powder using organic materials different from those of the conventional methods, and as a result, when the surface treatment of the magnetic metal powder is performed using stearic acid, The present invention has been proposed based on the fact that it can improve oxidation resistance.

본 발명은 표면처리되어야 할 자성금속분말의 전체 중량에 대하여 적정량의 스테아릭산을 유기용매에 녹인 용액에 자성금속분말을 침적하여 표면처리 하므로서, 내산화성이 우수한 자성금속분말을 얻을 수 있는 표면처리방법을 제공하고자 하는데, 그 목적이 있다.The present invention is a surface treatment method to obtain a magnetic metal powder having excellent oxidation resistance by immersing the magnetic metal powder in a solution dissolved in an appropriate amount of stearic acid in an organic solvent relative to the total weight of the magnetic metal powder to be surface treated It is intended to provide a purpose.

이하, 본 발명에 대하여 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

본 발명은 자성금속분말의 내산화성을 향상시키기 위하여 그 표면에 유기물 피막을 형성시키는 표면처리 방법에 있어서, 상기 자성금속분말의 전체중량에 대하여 0.5-10중량%의 스테아릭산을 유기용매에 용해시킨후, 여기에 자성금속분말을 침적하여 그 표면에 유기물 피막을 형성시킨 다음, 유기용매를 완전히 증발시켜 내산화성이 우수한 자성금속분말을 얻을 수 있는 표면처리방법에 관한 것이다.The present invention provides a surface treatment method for forming an organic film on the surface of the magnetic metal powder in order to improve the oxidation resistance of the magnetic metal powder, wherein 0.5-10% by weight of stearic acid is dissolved in an organic solvent based on the total weight of the magnetic metal powder. Thereafter, the magnetic metal powder is deposited thereon to form an organic film on the surface thereof, and then the organic solvent is completely evaporated to obtain a magnetic metal powder having excellent oxidation resistance.

상기한 본 발명의 목적은 통상적인 자성금속분말의 표면처리시 유기피복제로서 스테아릭산을 사용하는 것에 의해 그 달성이 가능하며, 이를 보다 상세히 설명하면 다음과 같다.The above object of the present invention can be achieved by using stearic acid as an organic coating agent in the surface treatment of conventional magnetic metal powder, which will be described in more detail as follows.

일반적으로 자성금속분말의 표면처리는 먼저 적정량의 유기피복제를 유기용매에 용해시킨다음, 여기에 자성금속분말을 침작하여 분말의 표면에 유기물 피막을 형성시킨후, 유기용매를 완전히 증발시키는 일련의 방법으로 이루어진다.In general, surface treatment of magnetic metal powder first dissolves an appropriate amount of organic coating agent in an organic solvent, and then precipitates the magnetic metal powder to form an organic film on the surface of the powder, and then completely evaporates the organic solvent. Is done in a way.

본 발명에서는 상기와 같은 방법으로 자성금속분말을 표면처리시 유기피복체로서 스테아릭산을 사용함이 바람직하다. 이러한 스테이릭산의 사용량은 표면처리 되어야 할 자성금속분말의 중량에 대하여 0.5중량% 이상 10중량%이하가 바람직한데, 그 이유는 스테아릭산의 사용량이 0.5중량% 이하일 경우에는 그 첨가에 의한 내산화성향상의 효과가 미흡하고, 스테아릭산의 사용량이 10중량% 이상일 경우에는 첨가에 따든 내산화성의 효과증대는 있으나, 자성금속분말중의 비자성물질(유기질피막) 증가로 금속분말의 자성이 저하될 우려가 있기 때문이다.In the present invention, it is preferable to use stearic acid as an organic coating when surface treatment of the magnetic metal powder in the same manner as described above. The amount of steric acid used is preferably 0.5% by weight or more and 10% by weight or less with respect to the weight of the magnetic metal powder to be surface-treated. When the amount of stearic acid is used, the oxidation resistance is improved by the addition If the effect is insufficient and the amount of stearic acid used is more than 10% by weight, the oxidation resistance may be increased depending on the addition. However, the magnetic property of the metal powder may be deteriorated due to the increase of the nonmagnetic material (organic coating) in the magnetic metal powder. Because there is.

본 발명에서는 상기와 같은 범위로 스테아릭산을 칭량한 다음, 통상의 방법으로 유기용매에 집어넣어 용해시키게 되는데, 이때 유기용매로는 스테아릭산을 용이하게 용해시킬 수 있는 것이면 어느것을 사용하더라도 무방하나, 취급성, 작업성 및 경제성 등을 고려하여 알코올, 톨루엔 및 벤젠중 선택된 1종을 사용함이 바람직하며, 보다 바람직하게는 알코올이다.In the present invention, the stearic acid is weighed in the range as described above, and then dissolved in the organic solvent by a conventional method. In consideration of handleability, workability and economy, it is preferable to use one selected from alcohol, toluene and benzene, and more preferably alcohol.

상기와 같이 유기용매에 스테아릭산을 용해시킨 후에는, 통상의 방법으로 본 발명에서 처리하고자 하는 자성금속분말을 침적하여, 그 표면에 유기물 피막을 형성시킨다음, 유기용매를 완전히 중발시키게 되면 표면에 자성분말의 자성을 해치지 않으면서 내산화성을 향상시키는 유기물 피막이 형성된 자성금속분말을 얻을 수 있다.After dissolving stearic acid in an organic solvent as described above, the magnetic metal powder to be treated in the present invention is deposited by a conventional method, and an organic film is formed on the surface thereof. It is possible to obtain a magnetic metal powder having an organic film which improves oxidation resistance without harming the magnetic properties of the magnetic powder.

이하, 본 발명을 실시예를 통하여 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

실시예 1Example 1

스테아릭산의 첨가 유무에 따른 자성금속분말의 자기적 특성 변화를 확인하기 위하여 다음과 같은 방법으로 자성금속분말을 표면처리하고, 내산화성을 측정하고 그 결과를 하기 표 1에 나타내었다.In order to confirm the magnetic property change of the magnetic metal powder with or without the addition of stearic acid, the magnetic metal powder was surface treated in the following manner, the oxidation resistance was measured and the results are shown in Table 1 below.

이때, 포화자화의 열화율(△Ms)은 하기 식을 이용하여 계산한 값이다.At this time, the deterioration rate (ΔMs) of saturation magnetization is a value calculated using the following formula.

(여기서, Ms0: 경시전의 포화자화, Ms:경시후의 포화자화, △Ms:포화자화의 열화율)(Ms 0 : saturation magnetization before aging, Ms: saturation magnetization after aging, ΔMs: deterioration rate of saturation magnetization)

발명예 1Inventive Example 1

스테아릭산 0.05g을 에틸알콜 30ml에 용해해서 처리액을 조제하고 이 처리액에 자성 금속분말(0.15㎛, 포화자화 142emu/g) 10g을 침적한 다음 용매를 완전히 증발시키고 60℃, 95%RH 공기중에서 1주간 방치해서 내산화성(표화자화의 열화율)을 측정하였다.0.05 g of stearic acid was dissolved in 30 ml of ethyl alcohol to prepare a treatment solution, and 10 g of magnetic metal powder (0.15 µm, saturated magnetization 142 emu / g) was immersed in the treatment solution, and then the solvent was completely evaporated. It was left to stand for 1 week in the inside, and oxidation resistance (degradation rate of a mark magnetization) was measured.

비교예 1Comparative Example 1

스테아릭산 대신 알콜을 사용한 것을 제외하고는 발명예 1의 경우와 동일한 방법으로 자성금속분말을 표면처리하고 내산화성을 측정하였다.The magnetic metal powder was surface treated and the oxidation resistance was measured in the same manner as in Example 1 except that alcohol was used instead of stearic acid.

비교예 2Comparative Example 2

스테아릭산 대신 타타릭산을 사용한 것을 제외하고는 발명예 1의 경우와 동일한 방법으로 자성금속분말을 표면처리하고 내산화성을 측정하였다.The magnetic metal powder was surface treated and the oxidation resistance was measured in the same manner as in Example 1 except that tartaric acid was used instead of stearic acid.

상기 표1에서 알수 있는 바와같이, 스테아릭산를 사용한 발명예(1)의 경우에는 경시변화에 따른 자성금속 분말의 내산화성(포화자화 열화율)이 우수한 반면에 스테아릭산을 사용하지 않고 알콜만을 단독으로 사용하여 본 발명의 범위를 만족하지 못하는 비교예(1) 및 타타릭산을 사용하여 본 발명의 범위를 만족하지 못하는비교예(2)의 경우에는 자성금속 분말의 내산화성, 즉 포화자화 열화율이 매우큼을 알 수 있다.As can be seen in Table 1, in the case of Inventive Example (1) using stearic acid, the oxidation resistance (saturation deterioration rate) of the magnetic metal powder according to the change with time is excellent, whereas only alcohol is used without using stearic acid. In the case of Comparative Example (1), which does not satisfy the scope of the present invention, and the Comparative Example (2), which does not satisfy the scope of the present invention, by using tartaric acid, the oxidation resistance of the magnetic metal powder, that is, You can see this is very large.

실시예 2Example 2

스테아릭산의 첨가량 변화에 따른 자성금속분말의 내산화성 변화를 확인하기 위하여, 다른 조건은 상기 실시예 1의 경우와 동일하게 유지한 채 스테아릭산의 첨가량만을 하기 표 2와 같이 변화시켜 가면서 자성금속분말의 내산화성 변화를 측정하고 그 결과를 하기 표 2에 나타내었다. 이때 자성금속분말의 내산화성 평가는 상기 실시예 1의 경우와 동일한 방법으로 평가하였다.In order to confirm the oxidation resistance of the magnetic metal powder according to the amount of stearic acid added, the magnetic metal powder was changed as shown in Table 2 while only the amount of stearic acid was changed while maintaining the same conditions as in Example 1. The change in oxidation resistance of was measured and the results are shown in Table 2 below. At this time, the oxidation resistance of the magnetic metal powder was evaluated in the same manner as in Example 1.

상기 표 2에서 알수 있는 바와같이, 스테아릭산의 첨가량이 본 발명의 범위를 만족하도록 된 발명예(2-6)의 경우에는 내산화성이 우수함을 알 수 있다. 반면에 스테아릭산의 첨가량이 본 발명의 범위를 만족하지 못하는 비교예(3, 4)의 경우에는 내산화성이 열화되어 자성이 열화됨을 알 수 있다.As can be seen in Table 2, in the case of Inventive Example (2-6) in which the amount of stearic acid is added to satisfy the scope of the present invention, it can be seen that the oxidation resistance is excellent. On the other hand, in the case of Comparative Examples (3, 4) in which the addition amount of stearic acid does not satisfy the scope of the present invention, it can be seen that the oxidation resistance is deteriorated and the magnetism is deteriorated.

상술한 바와같이, 본 발명은 자성금속분말의 표면처리시 표면처리되어야활자성금속분말의 전체 중량에 대하여 적정량의 스테아릭산을 유기용매에 녹인 용액에 자성금속 분말을 침적하여 표면처리 하므로서, 내산화성이 우수하여 경시안정성이 우수한 자성금속분말을 얻을 수 있는 표면처리방법을 제공할 수 있는 효과가 있다.As described above, the present invention should be surface-treated during the surface treatment of magnetic metal powder, oxidation of the magnetic metal powder in a solution in which stearic acid is dissolved in an organic solvent in an appropriate amount relative to the total weight of the magnetic metal powder. This has the effect of providing a surface treatment method to obtain a magnetic metal powder excellent in aging stability.

Claims (2)

자성금속분말의 내산화성을 향상시키기 위하여 그 표면에 유기물 피막을 형성시키는 표면처리 방법에 있어서,In the surface treatment method of forming an organic film on the surface in order to improve the oxidation resistance of the magnetic metal powder, 상기 자성금속분말의 전체중량에 대하여 0.5-10.0중량%의 프테아릭산을0.5-10.0 wt% of ptearic acid based on the total weight of the magnetic metal powder 유기용매에 용해시킨후, 여기에 자성금속분말을 침적하여 그 표면에 유기물 피막을 형성시킨 다음, 유기용매를 완전히 증발시키는 것을 포함하여 이루어짐을 특징으 로 하는 스테아릭산을 이용한 자성금속분말의 표면처리방법.After dissolving in an organic solvent, the magnetic metal powder is deposited thereon to form an organic film on the surface, and then surface treatment of the magnetic metal powder using stearic acid, characterized in that it comprises evaporating the organic solvent completely. Way. 제 1항에 있어서, 상기 유기용매는 알코올, 톨루엔 및 벤젠 중 선택된 1종인 것을 특징으로 하는 스테아릭산을 이용한 자성금속분말의 표면처리방법.The surface treatment method of magnetic metal powder using stearic acid according to claim 1, wherein the organic solvent is one selected from alcohol, toluene and benzene.
KR1019950048676A 1995-12-12 1995-12-12 Surface treatment method of magnetic metal powder using stearic acid KR100340489B1 (en)

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