JPH06250135A - Magneto-optical flaw detecting element - Google Patents
Magneto-optical flaw detecting elementInfo
- Publication number
- JPH06250135A JPH06250135A JP3342293A JP3342293A JPH06250135A JP H06250135 A JPH06250135 A JP H06250135A JP 3342293 A JP3342293 A JP 3342293A JP 3342293 A JP3342293 A JP 3342293A JP H06250135 A JPH06250135 A JP H06250135A
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- optical
- magnetic
- flaw detection
- gdbi
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Optical Integrated Circuits (AREA)
- Measuring Magnetic Variables (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁気光学効果を用いた
光磁界センサー、特に鋼板からの漏洩磁界を測定し、鋼
板の欠陥を検知する探傷に用いられる磁気光学探傷素子
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical magnetic field sensor using the magneto-optical effect, and more particularly to a magneto-optical flaw detection element used for flaw detection for detecting defects in a steel sheet by measuring a leakage magnetic field from the steel sheet.
【０００２】[0002]
【従来の技術】従来、鋼板の探傷は、鋼板表面の欠陥で
の光の散乱を検出する光学探傷、磁化した鋼板の欠陥か
らの漏洩磁界を検出する磁気探傷、超音波を利用する超
音波探傷が行われてきた。しかし、光学探傷は鋼板表面
の欠陥を高速で検出するには有効であるものの、鋼板内
部の欠陥検出は不可能であり、超音波探傷は鋼板端部に
不感帯を持つなどの欠点があった。2. Description of the Related Art Conventionally, flaw detection of a steel sheet is performed by optical flaw detection for detecting light scattering at a flaw on the surface of the steel sheet, magnetic flaw detection for detecting a leakage magnetic field from a defect of a magnetized steel sheet, or ultrasonic flaw detection using ultrasonic waves. Has been done. However, although optical flaw detection is effective for detecting defects on the surface of the steel sheet at high speed, it is impossible to detect flaws inside the steel sheet, and ultrasonic flaw detection has drawbacks such as a dead zone at the edge of the steel sheet.
【０００３】一方、磁気探傷は原理的に鋼板表面および
内部の欠陥の検出が鋼板全面にわたって可能である。こ
の磁気探傷では、磁粉探傷法と磁電変換素子を用いる方
法が実用化されているが、磁粉探傷法は検査時間が極め
て長く、磁電変換素子を用いる方法は微小な欠陥の検出
感度が悪いなどの欠点があった。On the other hand, in principle, magnetic flaw detection is capable of detecting defects on the surface and inside of the steel sheet over the entire surface of the steel sheet. In this magnetic flaw detection, a method using a magnetic particle flaw detection method and a magnetoelectric conversion element has been put to practical use, but the magnetic particle flaw detection method has an extremely long inspection time, and the method using the magnetoelectric conversion element has a poor detection sensitivity for minute defects. There was a flaw.
【０００４】これら従来の磁気探傷の問題点を解消する
ものとして、桜井らの特定研究「新しい光磁気材料の開
発と物性の研究」,p252(1989) に示されるような磁性ガ
ーネット膜を利用した磁気光学探傷法が提案された。In order to solve these problems of conventional magnetic flaw detection, a magnetic garnet film as shown in a specific study by Sakurai et al. "Development of new magneto-optical material and study of physical properties", p252 (1989) was used. A magneto-optical flaw detection method has been proposed.
【０００５】この方法も欠陥からの漏洩磁束を検出する
ため鋼板の外部および内部の欠陥を検出できることはも
とより、高速の検出が可能である。さらに、磁性ガーネ
ットの持つ数十μm 以下の磁区に対応する空間分解能も
有するため、微小な欠陥の検出も可能となるものであ
る。Since this method also detects the leakage magnetic flux from the defect, it is possible to detect defects outside and inside the steel sheet, as well as at high speed. Furthermore, since the magnetic garnet has a spatial resolution corresponding to a magnetic domain of several tens of μm or less, it is possible to detect minute defects.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、従来の
磁性ガーネットは、その応用が磁気バブルメモリー，光
アイソレータ，送配電線に流れる電流検出用センサなど
であり、磁気光学探傷法に適した感度を有するものはな
く、磁気光学探傷法はアイデアはあるものの未だ現実の
ものとはなっていない。However, the conventional magnetic garnet is applied to a magnetic bubble memory, an optical isolator, a sensor for detecting a current flowing in a transmission and distribution line, etc., and has a sensitivity suitable for a magneto-optical flaw detection method. There is nothing, and the magneto-optical flaw detection method has not been realized yet although it has an idea.
【０００７】本発明は、かかる実情に鑑み、磁気光学探
傷法に適した磁気光学探傷素子を提供することを目的と
する。In view of the above situation, it is an object of the present invention to provide a magneto-optical inspection element suitable for the magneto-optical inspection method.
【０００８】[0008]
【課題を解決するための手段】本発明による磁気光学探
傷素子は、(GdBi)3(Fe5-X AlX )O12の組成を持ち、ガド
リニウム・ガリウム・ガーネット単結晶基板上に液晶エ
ピタキシャル成長した磁性ガーネットであり、さらに(G
dBi)3(Fe5-X AlX )O12の組成において、X が、0.3 ≦ X
≦0.6 の範囲にあり、さらに、該素子の厚さd が、5 μ
m ≦ｄ≦60μmの範囲にあることを特徴としている。
尚、上記ガドリニウム・ガリウム・ガーネット単結晶基
板には(GdCa)3(GaMgZr)5O12 を含むものとする。A magneto-optical flaw detector according to the present invention has a composition of (GdBi) 3 (Fe 5-X Al X ) O 12 and is liquid crystal epitaxially grown on a gadolinium-gallium-garnet single crystal substrate. Magnetic garnet, and (G
dBi) 3 (Fe 5-X Al X ) O 12 In the composition, X is 0.3 ≤ X
≤0.6, and the thickness d of the device is 5 μm.
It is characterized in that m ≤ d ≤ 60 µm.
The gadolinium / gallium / garnet single crystal substrate contains (GdCa) 3 (GaMgZr) 5 O 12 .
【０００９】[0009]
【作用】磁気光学探傷法は鋼板を磁化し、鋼板の欠陥か
ら漏洩する磁界を磁性ガーネットの持つ磁気光学効果を
利用して検出するが、欠陥を検出する能力（以下欠陥検
出感度と称する）ｃは以下の式で表わされる。In the magneto-optical flaw detection method, the steel sheet is magnetized and the magnetic field leaking from the defect of the steel sheet is detected by utilizing the magneto-optical effect of the magnetic garnet. The ability to detect the defect (hereinafter referred to as defect detection sensitivity) c Is expressed by the following equation.
【００１０】 ｃ＝T2sin( 4θf ・d)/Hs ここで、 θf : ファラデー回転係数(deg./cm) d : 磁性ガーネットの厚さ Hs : 磁性ガーネットの飽和に要する磁界 T : 透過率 である。C = T 2 sin (4 θ f · d) / Hs where θ f : Faraday rotation coefficient (deg./cm) d: Thickness of magnetic garnet Hs: Magnetic field required for saturation of magnetic garnet T: Transmission Is the rate.
【００１１】一般に、鋼板の欠陥から出る漏洩磁界の大
きさは微弱であるために、欠陥検出感度は0.3 ％／0e以
上が必要である。上記式の分子は高々１であるため、
欠陥検出感度を大きくするには、飽和磁界Hsを小さくす
る必要がある。一般に、磁性ガーネットのHsは飽和磁化
Msに比例するため、欠陥検出が行われる温度である室温
付近で飽和磁化が小さくなる材料を探索した。Generally, since the magnitude of the leakage magnetic field generated from the defect of the steel sheet is weak, the defect detection sensitivity is required to be 0.3% / 0e or more. Since the numerator of the above formula is at most 1,
To increase the defect detection sensitivity, it is necessary to reduce the saturation magnetic field Hs. Generally, Hs of magnetic garnet is saturation magnetization
Since it is proportional to Ms, we searched for a material that has a small saturation magnetization near room temperature, which is the temperature at which defects are detected.
【００１２】この結果、室温付近に補償温度が存在する
(GdBi)3(Fe5-X AlX )O12が好適な材料であることが判っ
た。また、この分子式の Xを変化させることで飽和磁化
Ms(または飽和磁界Hs) を微妙に制御することが可能で
あることも確認でき、同時に飽和磁界Hsが膜厚に依存す
ることも確認できた。As a result, there is a compensation temperature near room temperature.
It has been found that (GdBi) 3 (Fe 5-X Al X ) O 12 is a suitable material. Also, the saturation magnetization can be changed by changing X in this molecular formula.
It was also confirmed that the Ms (or the saturation magnetic field Hs) can be finely controlled, and at the same time, it was also confirmed that the saturation magnetic field Hs depends on the film thickness.
【００１３】鋼板の磁極付近では欠陥が無い場合でも30
Oe 程度の漏洩磁界が発生する。飽和に要する磁界Hsを
この漏洩磁界より小さくしてしまうと、鋼板端部の欠陥
検出が全く不可能になってしまう。従って、余裕を以て
Hs≧40 Oe とすることが望ましい。Even if there is no defect near the magnetic pole of the steel plate, 30
A leakage magnetic field of about Oe is generated. If the magnetic field Hs required for saturation is made smaller than this leakage magnetic field, it will be impossible to detect defects at the edges of the steel sheet. Therefore, with a margin
It is desirable that Hs ≧ 40 Oe.
【００１４】これらのことを考慮すると欠陥検出感度
0.3％以上、飽和磁界Hs 40 Oe以上を満足するAl含有量
Xと 膜厚d(μm ) を限定することができる。Considering these things, the defect detection sensitivity
Al content that satisfies 0.3% or more and saturation magnetic field Hs 40 Oe or more
It is possible to limit X and the film thickness d (μm).
【００１５】[0015]
【実施例】以下、実施例により更に詳しく説明する。先
ず、液相エピタキシャル法により(GdBi)3(Fe5-X AlX )O
12で Xを変えた磁性ガーネット膜の製作を行った。白金
るつぼ中にPbO, Bi2O3, B2O3をフラックスとして、Gd2O
3,Fe2O3,Al2O3 を溶かし込んだ融液を作製した。EXAMPLES The present invention will be described in more detail below with reference to examples. First, by liquid phase epitaxial method, (GdBi) 3 (Fe 5-X Al X ) O
The magnetic garnet film with X changed at 12 was manufactured. PdO, Bi 2 O 3 and B 2 O 3 were used as flux in a platinum crucible to produce Gd 2 O.
A melt containing 3 , Fe 2 O 3 and Al 2 O 3 was prepared.
【００１６】該融液を約800 ℃に加熱しながら、融液表
面へガドリニウム・ガリウム・ガーネット単結晶基板を
付着させ回転させることにより、該基板の片面へ厚さ80
μmの(GdBi)3(Fe5-X AlX )O12磁性ガーネット膜を成長
させた。またその際、融液中のAl2O3 の量を変えること
により Xを変えた材料を作製した。育成後、各磁性ガー
ネット膜は10μm 〜70μm の厚さに研磨され試験試料と
した。While heating the melt to about 800 ° C., a gadolinium / gallium / garnet single crystal substrate is attached to the surface of the melt and rotated to give a thickness of 80% on one side of the substrate.
A μm (GdBi) 3 (Fe 5-X Al X ) O 12 magnetic garnet film was grown. At that time, materials with different X were prepared by changing the amount of Al 2 O 3 in the melt. After the growth, each magnetic garnet film was polished to a thickness of 10 μm to 70 μm and used as a test sample.
【００１７】これら試験試料について飽和磁界Hsおよび
ファラデー回転角θf を求めた。Hsは、波長 0.78 μm
の光を用いたファラデーループより求め、θf は、波長
0.78μm の光を用いて溝尻光学社製ファラデー回転角測
定装置により求めた。さらに、欠陥検出感度は求められ
たHSとθf を用いて式により算出した。The saturation magnetic field Hs and the Faraday rotation angle θ f were obtained for these test samples. Hs has a wavelength of 0.78 μm
Calculated from Faraday loop using the light, theta f is the wavelength
It was determined by a Faraday rotation angle measuring device manufactured by Mizojiri Optical Co., Ltd. using 0.78 μm light. Further, the defect detection sensitivity was calculated by an equation using the obtained HS and θ f .
【００１８】(GdBi)3(Fe5-X AlX )O12磁性ガーネット膜
のX および膜厚を変えたときの欠陥検出感度≧0.3 ％Oe
-1およびHs≧40 Oe を満足する領域を、縦軸に X, 横軸
に磁性ガーネット素子の膜厚d の関係図に表示すると、
図１の斜線部の如くになる。この斜線部は(GdBi)3(Fe
5-X AlX )O12の組成における Xが、 0.3 ≦ X≦0.6 の範囲にあり、さらに、膜厚d が、 5 μm ≦ｄ≦60μm の範囲にある領域であることを示している。(GdBi) 3 (Fe 5-X Al X ) O 12 Defect detection sensitivity ≧ 0.3% Oe when changing X and film thickness of the magnetic garnet film
-1 and the region satisfying Hs ≥ 40 Oe are displayed in the relational diagram of X on the vertical axis and film thickness d of the magnetic garnet element on the horizontal axis,
It becomes like the shaded area in FIG. This shaded area is (GdBi) 3 (Fe
It is shown that X in the composition of 5-X Al X ) O 12 is in the range of 0.3 ≤ X ≤ 0.6, and the film thickness d is in the range of 5 µm ≤ d ≤ 60 µm.
【００１９】該領域の磁性ガーネット膜を用いて、３ｍ
幅鋼板の探傷を行った結果、鋼板全面で50μm 程度の微
小欠陥を検出することができ、十分に実用可能であるこ
とを確認した。Using the magnetic garnet film in the area,
As a result of flaw detection on the width steel sheet, it was confirmed that a micro defect of about 50 μm could be detected on the entire surface of the steel sheet, which was sufficiently practical.
【００２０】[0020]
【発明の効果】上述のように本発明による磁気光学探傷
素子は、鋼板の微小欠陥を高感度で検出する磁気光学探
傷に用いる材料として好適である。As described above, the magneto-optical flaw detector according to the present invention is suitable as a material used for magneto-optical flaw detection for detecting minute defects in a steel sheet with high sensitivity.
【図１】本発明による(GdBi)3(Fe5-X AlX )O12磁性ガー
ネット膜における欠陥検出感度ｃが、ｃ≧0.3 ％Oe-1お
よび飽和に要する磁界Hsが、Hs≧40 Oe を満足する磁気
光学探傷で用いるときの好適な領域図を示す。斜線区域
は好適領域である。FIG. 1 is a defect detection sensitivity c of (GdBi) 3 (Fe 5-X Al X ) O 12 magnetic garnet film according to the present invention, c ≧ 0.3% Oe −1, and a magnetic field Hs required for saturation is Hs ≧ 40 Oe. The suitable area | region figure when using by the magneto-optical flaw detection which satisfy | fills is shown. The shaded area is the preferred area.
Claims (2)
る磁気光学探傷素子において、該素子が(GdBi)3(Fe5-X
AlX )O12の組成を持ちガドリニウム・ガリウム・ガーネ
ット単結晶基板上に液晶エピタキシャル成長した磁性ガ
ーネットであることを特徴とした磁気光学探傷素子。1. A magneto-optical flaw detection element used for flaw detection utilizing the magneto-optical effect, wherein the element is (GdBi) 3 (Fe 5-X
A magneto-optical flaw detector having a composition of Al X ) O 12 and a magnetic garnet epitaxially grown on a gadolinium-gallium-garnet single crystal substrate.
成において、X が、0.3 ≦ X≦0.6 の範囲にあり、さら
に、該素子の厚さd が、 5μm ≦ｄ≦60μmの範囲にあ
ることを特徴とした請求項１に記載の磁気光学探傷素
子。2. In the composition of the element of (GdBi) 3 (Fe 5-X Al X ) O 12 , X is in the range of 0.3 ≤ X ≤ 0.6, and the thickness d of the element is 5 μm. The magneto-optical flaw detector according to claim 1, wherein the range is ≤d≤60 µm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3342293A JPH06250135A (en) | 1993-02-23 | 1993-02-23 | Magneto-optical flaw detecting element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3342293A JPH06250135A (en) | 1993-02-23 | 1993-02-23 | Magneto-optical flaw detecting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06250135A true JPH06250135A (en) | 1994-09-09 |
Family
ID=12386133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3342293A Pending JPH06250135A (en) | 1993-02-23 | 1993-02-23 | Magneto-optical flaw detecting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06250135A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6088725A (en) * | 1996-08-02 | 2000-07-11 | Hitachi, Ltd. | Mobile computer supporting system, its administrative server, its terminal, and address conversion method |
-
1993
- 1993-02-23 JP JP3342293A patent/JPH06250135A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6088725A (en) * | 1996-08-02 | 2000-07-11 | Hitachi, Ltd. | Mobile computer supporting system, its administrative server, its terminal, and address conversion method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Okamoto et al. | Chemical-order-dependent magnetic anisotropy and exchange stiffness constant of FePt (001) epitaxial films | |
| Munford et al. | Electrodeposition of magnetic thin films of cobalt on silicon | |
| Schlenker et al. | Polarized neutron techniques for the observation of ferromagnetic domains | |
| JP3198053B2 (en) | Products made of magneto-optical material with low magnetic moment | |
| Scheel et al. | Crystal growth and characterization of “striation-free” KTa1− xNbxO3 (x≈ 0.26) solid solutions | |
| Grechishkin et al. | Magnetic imaging films | |
| JPH06250135A (en) | Magneto-optical flaw detecting element | |
| US4806858A (en) | Liquid crystal nondestructive inspection of magnetization and variations in magnetization of high energy magnets | |
| Görnert et al. | Liquid phase epitaxy (LPE) grown Bi, Ga, Al substituted iron garnets with huge Faraday rotation for magneto‐optic applications | |
| Nikitenko et al. | Direct experimental study of the magnetization reversal process in epitaxial and polycrystalline films with unidirectional anisotropy | |
| Kida et al. | Optical magnetoelectric effect in a submicron patterned magnet | |
| JPH0735727A (en) | Magnetooptic flaw detecting element | |
| Krumme et al. | Local magnetocrystalline and induced anisotropies in liquid‐phase epitaxial garnet films | |
| Hussain et al. | Role of anti-ferromagnetic layer thickness in exchange bias: Case study of Co/CoO with Kerr microscopy | |
| Shamonin et al. | Feasibility of magneto-optic flaw visualization using thin garnet films | |
| Vishnevskii et al. | Magneto-optic eddy current introscopy based on garnet films | |
| Craik et al. | The evaluation of magnetic bubble domain specimens | |
| Takeno et al. | Structure and Magnetic Properties of MnBi Thin Films | |
| Petford-Long et al. | The effects of annealing on magnetic domain structure and interface profile in sputtered Fe/Cr multilayer films | |
| Pollmann et al. | Magnetic imaging of a buried SmCo layer in a spring magnet | |
| JPH03267782A (en) | Detection of magnetic internal characteristic of superconductor, detector and thin-film member for detection | |
| Fitzpatrick | Imaging near surface flaws in ferromagnetic materials using magneto-optic detectors | |
| Baird et al. | Magnetic switching, relaxation, and domain structure of a Co/Si (111) film | |
| Fisher et al. | Size effect in anisotropic hard superconductors | |
| JPH03249566A (en) | Magneto-optical film for magnetic field sensor |