JPS58204155A - Corrosion-resistant alloy with high saturation magnetic flux density and high magnetic permeability - Google Patents

Abstract

PURPOSE:To obtain a corrosion-resistant alloy with high saturation magnetic flux density, high magnetic permeability and enhanced acid resistance, by adding small amounts of Ti and Zr to an Fe-Si-Al alloy and by regulating the amount of S among the impurities in the alloy. CONSTITUTION:This corrosion-resistant alloy with high saturation magnetic flux density and high magnetic permeability consists of, by weight, 4-12% Si, 3-8% Al, 0.1-1.0% Ti, 0.01-1.0% Zr and the balance essentially Fe or further contains 0.02-0.5% Ru. The amount of S remaining in the alloy is regulated to 3-30ppm. Ti and Zr are added to passivate the alloy surface. Since the alloy contains reduced amounts of S and sulfide which form rusting spots when the alloy is exposed to an oxidizing atmosphere for a long time, pitting corrosion can be prevented. The alloy has superior acid resistance and high magnetic flux density, so it is suitable for use as the material of the core of a magnetic head.

Description

【発明の詳細な説明】 本発明ｒ／′１Ｆｅ−８ｔ−Ａｔ磁性合金に関し、特に
酸性雰囲気における耐食性、すなわち耐酸性に優れた高
飽和磁束密度高透磁率合金に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an r/'1Fe-8t-At magnetic alloy, and particularly to a high saturation magnetic flux density and high magnetic permeability alloy that has excellent corrosion resistance in an acidic atmosphere, that is, excellent acid resistance.

一般に磁気へラドコア用礫性材料が具備すべき特性は、
磁気記録媒体の摺動に対する耐摩耗性が良く、記録媒体
を完全に磁化するために飽和磁束密度が高く、磁気ヘッ
ドの感度に関係した透磁率が高く、記録媒体による帯磁
を防ぐために保磁力が低いとと、さらには、いかなる環
境においても使用が可能なために耐食性に優れているこ
と等が挙げられる。In general, the characteristics that the gravel material for magnetic helad core should have are as follows:
The magnetic recording medium has good wear resistance against sliding, high saturation magnetic flux density to completely magnetize the recording medium, high magnetic permeability related to the sensitivity of the magnetic head, and low coercive force to prevent magnetization by the recording medium. In addition, it has excellent corrosion resistance because it can be used in any environment.

従来、磁気へラドコア用礫性材料としては。Traditionally, it has been used as a gravel material for magnetic helad cores.

パーマロイ、ソフトフェライト等が使用されているが、
パーマロイは耐摩耗性が悪く、ソフトフェライトは飽和
磁束密度が低いという欠点を有している。Permalloy, soft ferrite, etc. are used,
Permalloy has poor wear resistance, and soft ferrite has a low saturation magnetic flux density.

最近、オーディオ分野およびＶＴＲ分野において記録密
度の高い磁気記録媒体としてメタルテープ、蒸着テープ
等が普及しておシ、さらにＶＴＲ分野においては狭トラ
ンク化、狭ギャップ長化が進んでいることから、高飽和
磁束密度。Recently, metal tapes, vapor-deposited tapes, etc. have become popular as high-density magnetic recording media in the audio and VTR fields, and furthermore, in the VTR field, trunks are becoming narrower and gap lengths are becoming narrower. Saturation magnetic flux density.

すなわち印加磁場１０エルステツドにおける磁束密度（
以下Ｂ＋ｏ　）が９３００ガウス以上を有し、耐摩耗性
を兼ね備えた磁気へラドコアが要求されている。That is, the magnetic flux density (
There is a demand for a magnetic herad core having B+o) of 9300 Gauss or more and having wear resistance.

ソコテ、パーマロイ、フェライトの欠点を補１い、さら
に上記要求全満足する磁性材料としてＦｅ−８ｔ−Ａｔ
磁性合金が最近注目されている。Fe-8t-At is a magnetic material that compensates for the shortcomings of Sokote, permalloy, and ferrite, and also satisfies all of the above requirements.
Magnetic alloys have been attracting attention recently.

Ｆｅ−８ｉ−Ａｔ磁性合金はへラドコア材として優れた
磁気特性を有しているが、主体元素がＦｅであるために
耐食・性が十分でないという問題がある。The Fe-8i-At magnetic alloy has excellent magnetic properties as a herad core material, but since the main element is Fe, there is a problem that the corrosion resistance and properties are insufficient.

ところで磁気記録媒体、特に磁気録音用テープを蒸留水
（ｐＨ＝７）中に浸漬すると、磁気テープのバインダー
が溶は出し、蒸留水は、　ｐＨ＝３．７程度にまで変化
し酸性を呈するようになる。このため、Ｆｅ−８ｔ−Ａ
ｔ磁性合金をヘッドコア材として使用した場合、コアは
、磁気テープとの摺接により常に酸性雰囲気にさらされ
るので、長時間の使用により腐食が生じる。磁気テープ
摺動面に腐食が生じるとテープ走行が妨げられ。By the way, when a magnetic recording medium, especially a magnetic recording tape, is immersed in distilled water (pH = 7), the binder of the magnetic tape dissolves, and the distilled water changes to pH = 3.7, becoming acidic. become. Therefore, Fe-8t-A
When a magnetic alloy is used as a head core material, the core is constantly exposed to an acidic atmosphere due to sliding contact with the magnetic tape, so corrosion occurs over long periods of use. If corrosion occurs on the sliding surface of the magnetic tape, tape running will be hindered.

また、腐食摩耗という現象により耐摩耗性が著しく劣化
し、さらにスペーシング損失をもたらし出力低下のもと
になる。In addition, the wear resistance is significantly deteriorated due to the phenomenon of corrosive wear, which further causes spacing loss, resulting in a decrease in output.

一般に鉄合金の耐食性は不働態化現象に基づいており、
高い耐食性を得るためには強固な不働態皮膜を形成させ
ると良い。しかし不働態皮膜を形成させても、孔食とい
う局部腐食に弱いという大きな欠講がある。このためこ
の欠点を克服するためには合金中に存在するＣ、Ｎ、Ｐ
、Ｓなどの不純物元素を低下させる必要がある。この中
でも特にＳが耐食性を著しく劣下させることから、Ｓを
極力低下させる必要がある。In general, the corrosion resistance of iron alloys is based on the passivation phenomenon,
In order to obtain high corrosion resistance, it is preferable to form a strong passive film. However, even if a passive film is formed, it is susceptible to localized corrosion called pitting corrosion, which is a major problem. Therefore, in order to overcome this drawback, C, N, and P present in the alloy must be
, S, and other impurity elements need to be reduced. Among these, S in particular significantly deteriorates corrosion resistance, so it is necessary to reduce S as much as possible.

本発明者らはＦｅ−８ｔ−Ａｔ磁性合金の耐食性におい
ても上記の一般の鉄合金と同様であることを見い出した
。すなわち、Ｆｅ−８ｔ−Ａｔ磁性合金に不働態皮膜を
形成させる合金元素を添加しても、不純物に起因する孔
食という局部腐食を押えることが不可能であった。本発
明者等は、このようなＦｅ−８ｔ−Ａｔ磁性合金の孔食
の原因となる不純物は主としてＳであり、このＳ量ヲ３
０ｐｐｍ以下にすると孔食によるＦｅ−８ｉ−Ａ７磁性
合３− 金の局部腐食を著しく改善できることを見出した。The present inventors have discovered that the corrosion resistance of the Fe-8t-At magnetic alloy is also similar to that of the above-mentioned general iron alloy. That is, even if an alloying element that forms a passive film is added to the Fe-8t-At magnetic alloy, it has been impossible to suppress localized corrosion called pitting corrosion caused by impurities. The present inventors have discovered that the impurity that causes pitting corrosion in such Fe-8t-At magnetic alloys is mainly S, and that the amount of S is 3
It has been found that local corrosion of the Fe-8i-A7 magnetic alloy 3-metal due to pitting corrosion can be significantly improved when the content is 0 ppm or less.

本発明は、上述した新たな知見にもとづいてなされたも
のである。The present invention has been made based on the above-mentioned new findings.

すなわち本発明の第一の発明は、Ｓｉ４〜１２％（重量
％、以下同じ）、Ａｔ５〜８％、　Ｔｉ　Ｏ，１〜１．
０％。That is, the first invention of the present invention has Si4 to 12% (wt%, same hereinafter), At 5 to 8%, TiO, 1 to 1.
0%.

Ｚｒ０．０１〜１．０％および残部が実質的にＦｅから
なる合金であって、該合金中に残存するＳ量が３〜３０
　ｐｐｍであり、酸性雰囲気における耐食性に優れ、か
つＢＩＯが９３００ガウス以上を有する耐食性高飽和磁
束密度高透磁率合金である。An alloy consisting of Zr0.01 to 1.0% and the balance substantially Fe, and the amount of S remaining in the alloy is 3 to 30%.
ppm, is excellent in corrosion resistance in an acidic atmosphere, and is a corrosion-resistant high saturation magnetic flux density high magnetic permeability alloy having a BIO of 9300 Gauss or more.

また第二の発明は、Ｓｉ４〜１２チ、Ａ７３〜８チ。Moreover, the second invention is Si4-12th and A73-8th.

Ｔ　ｉ　Ｏ，１〜１．０％、　Ｚｒ　Ｏｌｏ　１〜１．
０　％’＋　Ｒｕ　Ｏ，０２〜０．５　％および残部が
実質的にＦｅからなる合金であって。T i O, 1-1.0%, Zr Olo 1-1.
0%'+RuO, 02-0.5%, and the balance substantially consists of Fe.

該合金中に残存するＳ量が３〜３０　ｐｐｍであシ、酸
性雰囲気における耐食性に優れ、かつＢＩＧが９３００
ガウス以上を有する耐食性高飽和磁束密度高透磁率合金
である。The amount of S remaining in the alloy is 3 to 30 ppm, has excellent corrosion resistance in an acidic atmosphere, and has a BIG of 9300.
It is a corrosion-resistant, high saturation magnetic flux density, and high magnetic permeability alloy with Gauss or higher.

本発明において、　Ｓｊは７〜１０チが最適であるが、
に４Ｆｅ等の関係から４〜１２％の範囲におい４− ても十分良好な磁気特性を有するので下限を４チ、上限
’ｉ　１２％とした。Ａｔの量は４〜６％が最適である
が、６〜８チの範囲においても十分良好な特性を有する
ので下限を６％、上限を８％とした。In the present invention, Sj is optimally between 7 and 10, but
In view of the relationship between 4Fe and the like, the lower limit was set at 4% and the upper limit was set at 12% because even 4% had sufficiently good magnetic properties in the range of 4% to 12%. The optimum amount of At is 4 to 6%, but the lower limit is set to 6% and the upper limit is set to 8% because the properties are sufficiently good even in the range of 6 to 8 inches.

Ｔｉ及びＺｒは合金表面を不働態化させるために添加す
るものであシ、添加量がＴｉ０．１％未満あるいはＺｒ
［１，０１％未満では効果が小さく、また両者いずれに
ついても１．０％’ｅ越えるとＴｉおよびＺｒが結晶□
粒界に析出し粒界腐食の原因となると共にＢ＋ｏ　’ｌ
：低下させる要因となることがら。Ti and Zr are added to passivate the alloy surface, and if the amount added is less than 0.1% Ti or Zr
[If it is less than 1.01%, the effect will be small, and if it exceeds 1.0%'e for both, Ti and Zr will crystallize □
B+o'l precipitates at grain boundaries and causes intergranular corrosion.
: Factors that may cause a decline.

添加量ｉＴ＋は０．１〜’１．０　％およびＺｒはｏ、
ｏ　１〜１．０　％とした。Addition amount iT+ is 0.1 to '1.0%, Zr is o,
o 1 to 1.0%.

第二の発明において添加するＲｕも合金表面を不働態化
させるのに有効な元素であり、　ＴｉおよびＺｒだけよ
りもＲｕ　Ｏ，０２〜０．５％とＴｉおよびｚｒを複合
添加した方がより一層耐食性は改善される。Ｒｕ添加量
が０．０２％以下では添加効果が小さく＋Ｈの場合と大
差がない。また ０、５％を越えて添加しても、より一層の耐食性の改善
は認め難（，０，０２〜０５チの添加で十分である。The Ru added in the second invention is also an effective element for passivating the alloy surface, and it is better to add 02 to 0.5% Ru O, Ti and Zr in combination than just Ti and Zr. Corrosion resistance is further improved. When the amount of Ru added is 0.02% or less, the effect of addition is small and there is no significant difference from the case of +H. Moreover, even if it is added in an amount exceeding 0.5%, it is difficult to see any further improvement in corrosion resistance (addition of 0.02 to 0.05% is sufficient.

Ｆｅ−８ｔ−Ａｔ磁性合金の酸性雰囲気における腐食形
態は９合金中に残存するＳおよび硫化物が起請点となる
孔食から始まり、長時間酸性雰囲気にさらされると全面
腐食へと進行する形態である。そこで孔食全防止させる
ためには起請点の原因となる合金中のＳおよび硫化物全
低減させる必要がある。すなわち合金中に残存するＳ量
′ｆｆ：３〜３０　ｐｐｍにすると孔食全防止できる。The form of corrosion of Fe-8t-At magnetic alloys in an acidic atmosphere begins with pitting caused by S and sulfides remaining in the 9 alloy, and progresses to full-scale corrosion when exposed to an acidic atmosphere for a long time. be. Therefore, in order to completely prevent pitting corrosion, it is necessary to completely reduce S and sulfides in the alloy, which cause pitting points. That is, when the amount of S remaining in the alloy is set to 3 to 30 ppm, pitting corrosion can be completely prevented.

Ｓ量に３ｐｐｍ未満にすることは工業的には相当困難で
あり、３０ｐｐｍｉ越えるとＴｉおよびＺｒあるいはＴ
ｉとＺｒとＲｕにより合金表面を不働態化させても孔食
を防止することはできない。It is industrially difficult to reduce the amount of S to less than 3 ppm, and if it exceeds 30 ppm, Ti and Zr or T
Even if the alloy surface is made passivated by i, Zr, and Ru, pitting corrosion cannot be prevented.

ところで合金中に残存するＳ量の大部分子”ＪＦｅ原料
から持ち込まれるものであるから２合金中のＳ量を低下
させるためにばＦｅ原料中のＳ量を低下させれば良い。By the way, most of the amount of S remaining in the alloy is brought in from the molecular JFe raw material, so in order to reduce the amount of S in the two alloys, it is sufficient to reduce the amount of S in the Fe raw material.

工業的に用いられているＦｅ原料中には５０〜１１００
ｐｐのＳが存在しているので、とのＦｅ原料を用いて真
空溶解しても合金中には４０〜８０　ｐｐｍ程度のＳが
残存する。　そこで。Fe raw materials used industrially contain 50 to 1100
Since there are ppm of S, about 40 to 80 ppm of S remains in the alloy even if vacuum melting is performed using the Fe raw material. Therefore.

まずＦｅ原料のみを溶解しフラックス処理精錬を行なう
ことによりＳ量が３０　ｐｐｍ以下の高純度鉄を作製し
、この高純度鉄を用いてＦｅ−８ｔ−Ａｔ磁性合金を溶
製すると９合金中に残存するＳ量を３０ｐｐｍ以下にす
ることが可能である。First, high-purity iron with an S content of 30 ppm or less is produced by melting only the Fe raw material and performing flux treatment and refining, and when Fe-8t-At magnetic alloy is melted using this high-purity iron, 9 alloys are produced. It is possible to reduce the amount of remaining S to 30 ppm or less.

次に本発明の実施例について述べる。Next, examples of the present invention will be described.

Ｓ含有量が８０ｐｐｍである通常のＦｅ原料５０に）を
アルゴンガス雰囲気中で溶解し、ｐ、ｔ１５．ｐ＊添加
して脱酸を行ない、その後６５％Ｃａｂ−１５％ＣａＦ
２−２０％　Ａｚ２ｏ３よりなるフラックスを溶湯表面
が常にフラックスによって被われるように。A normal Fe raw material 50 with an S content of 80 ppm) was dissolved in an argon gas atmosphere, and p, t15. Add p* to perform deoxidation, then 65% Cab-15% CaF
Apply a flux consisting of 2-20% Az2O3 so that the surface of the molten metal is always covered with the flux.

３０分間に３回以上にわたって添加した。　こうして精
錬したＦｅ原料についてＳおよびＯの含有量を分析した
結果を第１表に示す。It was added three times or more over a period of 30 minutes. Table 1 shows the results of analyzing the S and O contents of the Fe raw material refined in this way.

第１表 とれより、Ｓ含有量の低い高純度鉄を得ることが可能で
あり、この高純度鉄原料を用いてＦｅ−８ｉ−Ａｔ磁性
合金を従来法と同様にして溶製すると２合金中に残存す
るＳ量’に３０ｐｐｍ以下にすることが可能である。From Table 1, it is possible to obtain high-purity iron with a low S content, and when Fe-8i-At magnetic alloy is melted using this high-purity iron raw material in the same manner as the conventional method, it is possible to obtain one of the two alloys. It is possible to reduce the amount of S remaining in the steel to 30 ppm or less.

第２表に種々の合金の組成、磁気特性および耐酸試験の
結果を示す。なお９合金１〜３は比較例でＳ量を５０　
ｐｐｍ以下に調整しなかったものであり９合金４〜２ｏ
が本発明の実施例である。Table 2 shows the composition, magnetic properties and acid resistance test results of various alloys. In addition, 9 alloys 1 to 3 are comparative examples with an S content of 50
It is not adjusted to ppm or less, and the alloy 9 is 4-2o
is an example of the present invention.

試験片の寸法は下記のとおシであり、各試験片は所定の
熱処理を施したのち磁気特性の測定。The dimensions of the test pieces are as shown below, and each test piece was subjected to a specified heat treatment before its magnetic properties were measured.

および耐酸試験に供された。and was subjected to acid resistance tests.

磁気特性測定用試験片は、外径８咽、内径４調、厚さ０
．２ｍで、耐酸試験用試験片は直径３０叫、厚さ５ＷＩ
ｎであった。The test piece for measuring magnetic properties has an outer diameter of 8 mm, an inner diameter of 4 mm, and a thickness of 0.
．． 2m, the acid resistance test specimen has a diameter of 30mm and a thickness of 5wi.
It was n.

耐酸試験は、２０チ塩酸水溶液（３０’Ｃ）’に用い。For acid resistance test, 20% hydrochloric acid aqueous solution (30'C)' was used.

これ［１分間浸漬する方法とし、評価方法は１ｃｍあた
りに生じる孔食数（財）の比較としだ。This method was immersed for 1 minute, and the evaluation method was to compare the number of pitting corrosion occurring per 1 cm.

第２表より明らかな如く、Ｓ量が３０ｐｐｍを越えてい
る場合は、ＴｉおよびＺｒあるいはＴｉ　、　Ｚｒおよ
びＲｕｉ添加しても１ｃｍあたシの孔食数（へ）は著し
く多いが、Ｓ量を３０　ｐｐｍ以下にすると１ＣＴｎあ
たりの孔食数は１０個以下と大幅に改善されている。さ
らに２合金番号９および１２（Ｓ＝　５　ｐｐｍ　）は
、それぞれ、０３％Ｔｉ−０，５％Ｚｒ−０，３％Ｒｕ
および０．３　％　Ｔｉ　−０，７％Ｚｒ−０，１％　
Ｒｕ　ｋ添加することにより１ｃＩｎあたりの孔食数は
０個とな９゜本条件下では全く孔食が見られなかった。As is clear from Table 2, when the amount of S exceeds 30 ppm, even if Ti and Zr or Ti, Zr and Rui are added, the number of pitting corrosion per 1 cm is significantly increased, but the amount of S is When the amount of pitting corrosion is reduced to 30 ppm or less, the number of pitting corrosion per 1 CTn is significantly improved to 10 or less. Further two alloy numbers 9 and 12 (S = 5 ppm) are 03%Ti-0,5%Zr-0,3%Ru, respectively.
and 0.3% Ti-0,7% Zr-0,1%
By adding Ru k, the number of pitting corrosion per cIn was 0, and no pitting corrosion was observed under this 9° condition.

この結果、　Ｆｅ７Ｓｉ−ＡＡ金合金Ｔｉ　ｆ　０．１
〜１．０　％。As a result, Fe7Si-AA gold alloy Ti f 0.1
~1.0%.

Ｚｒ’ｔ０．０１〜１．０％含有し、かつ合金中に残存
するＳ量が３〜３０ｐｐｍの範囲にあることが耐酸性を
改善するために最適な値であることが明らかであり、ま
た、さらにＲｕを０．０２〜０．５チ含有させることに
よシ、一層耐酸性が改善されることが明らかである。It is clear that containing 0.01 to 1.0% Zr't and having the amount of S remaining in the alloy in the range of 3 to 30 ppm is the optimal value for improving acid resistance, and It is clear that the acid resistance is further improved by further containing Ru in an amount of 0.02 to 0.5.

以上述べた如く９本発明によれば、上述のように構成し
たので、耐酸性に優れ、しかも磁束密度の大きい合金を
得ることが可能である。従って１本発明による合金を磁
気ヘッド材として使用して好適である。As described above, according to the present invention, which is constructed as described above, it is possible to obtain an alloy having excellent acid resistance and high magnetic flux density. Therefore, the alloy according to the present invention is suitable for use as a magnetic head material.

代理人（７１２７）弁理士後藤洋介Agent (7127) Patent attorney Yosuke Goto

Claims (1)

【特許請求の範囲】 １、重量％でＳｉ４〜１２％、ｋｔ５〜８チ、ＴｉＯ，
１〜１．０　％、　Ｚｒ　０．０１〜１．０　％および
残部が実質的にＦｅからなる合金であって、該合金中に
残存するＳｉが６〜３０ｐｐｍであることを特徴とした
耐食性高飽和磁束密度高透磁率合金。 ２、重量％でＳｉ４〜１２チ、ｋｔ５〜８％、Ｔｉ０．
１〜１．０　％、　Ｚｒ　０．０１〜１．０　％、　Ｒ
ｕ　Ｏ，０２〜０．５％および残部が実質的にＦｅから
なる合金であって、該合金中に残存するＳｉが３〜３０
ｐｐｍであることを特徴とする耐食性高飽和磁束密度高
透磁率合金。[Claims] 1. Si 4-12% by weight, kt 5-8 Ti, TiO,
1 to 1.0%, Zr 0.01 to 1.0%, and the balance substantially consisting of Fe, and the alloy has high corrosion resistance, characterized in that the amount of Si remaining in the alloy is 6 to 30 ppm. Saturation magnetic flux density high permeability alloy. 2. Si4-12% by weight, kt5-8%, Ti0.
1-1.0%, Zr 0.01-1.0%, R
u An alloy consisting of O, 02 to 0.5% and the balance substantially Fe, and the remaining Si in the alloy is 3 to 30%.
A corrosion-resistant high saturation magnetic flux density high magnetic permeability alloy characterized by a ppm.