JP2006064419A - Magnetization measuring method, and magnetization measuring instrument for executing same - Google Patents
Magnetization measuring method, and magnetization measuring instrument for executing same Download PDFInfo
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Abstract
Description
本発明は超伝導磁石を用いた電磁誘導法による磁化測定方法とその磁化測定装置に関する。詳しくは、強磁界を必要とする高性能磁石の測定、あるいは、従来のものでは測定が困難であった大型の高性能磁石の測定に適した、超伝導磁石を利用した永久磁石の磁化測定方法とこの方法を実施する磁化測定装置に関する。さらに詳しくは、本発明は、可動部分を持たない磁化測定方法とその装置に関する。 The present invention relates to a magnetization measuring method by an electromagnetic induction method using a superconducting magnet and a magnetization measuring apparatus therefor. Specifically, the method for measuring the magnetization of permanent magnets using superconducting magnets is suitable for measuring high-performance magnets that require strong magnetic fields, or large-scale high-performance magnets that were difficult to measure with conventional magnets. And a magnetization measuring apparatus for carrying out this method. More particularly, the present invention relates to a magnetization measuring method and apparatus having no moving parts.
永久磁石の性能はＪ−Ｈ履歴曲線から評価されるが、現在このＪ−Ｈ履歴曲線を得る方法として鉄芯電磁石を用いた閉磁気回路法が広く行われている。これは電磁石の作る磁界により試料を磁化させ、そのときに試料に巻いたピックアップコイルに生じる誘導起電力から磁化を求める方法である。これは安価かつ簡便な方法であるが、鉄芯の磁気的飽和のため１．２Ｔ程度が発生磁界であるとされており、近年広く使用されている希土類を用いた高性能磁石の測定には十分でない（非特許文献１参照）。 The performance of the permanent magnet is evaluated from the JH history curve. Currently, a closed magnetic circuit method using an iron core electromagnet is widely used as a method for obtaining the JH history curve. This is a method in which a sample is magnetized by a magnetic field produced by an electromagnet, and magnetization is obtained from an induced electromotive force generated in a pickup coil wound around the sample at that time. This is an inexpensive and simple method, but due to the magnetic saturation of the iron core, about 1.2T is considered to be the generated magnetic field. For the measurement of high-performance magnets using rare earths widely used in recent years, It is not enough (see Non-Patent Document 1).
これらの高性能磁石の測定に十分な磁界を発生させるにはパルス磁石または超伝導磁石を用いる必要がある。パルス磁石を用いた永久磁石測定は、パルス磁界により生じる試料の磁化過程を試料に巻かれたピックアップコイルの誘導起電力の変化から計算するもので、詳細は、非特許文献２、３に示されている。この方法は短時間で測定できるという長所をもつが、大型の試料を測定する場合は、磁束が試料の中心まで入ることができず正確な測定が難しい。パルス幅を十分に大きくすればこの問題は解決できるが、試料の大きさ、形状、電気伝導率等により異なり、これを規定することは難しく、いずれにしても装置が非常に大がかりになってしまう。 In order to generate a magnetic field sufficient for measurement of these high-performance magnets, it is necessary to use a pulse magnet or a superconducting magnet. In the permanent magnet measurement using a pulse magnet, the magnetization process of the sample caused by the pulse magnetic field is calculated from the change in the induced electromotive force of the pickup coil wound around the sample. Details are shown in Non-Patent Documents 2 and 3. ing. This method has the advantage of being able to measure in a short time, but when measuring a large sample, the magnetic flux cannot reach the center of the sample, making accurate measurement difficult. This problem can be solved by making the pulse width sufficiently large, but it depends on the size, shape, electrical conductivity, etc. of the sample, and it is difficult to define this, and in any case, the apparatus becomes very large. .
超伝導磁石を用いる方法では引き抜き法が良く知られている。これは超伝導磁石の作る磁界中に置かれたピックアップコイルを試料が通過することにより生じる起電力から試料の磁化を測定するものである（非特許文献４参照）。この測定方法の特徴は、超伝導磁石の作る強磁界中を永久磁石試料が移動するため、移動機構には大きな力が加わる。特に大型の試料を測定したい場合は相当に堅牢なものを用いる必要がある。 As a method using a superconducting magnet, a drawing method is well known. This measures the magnetization of the sample from the electromotive force generated when the sample passes through a pickup coil placed in a magnetic field created by a superconducting magnet (see Non-Patent Document 4). A characteristic of this measurement method is that a permanent magnet sample moves in a strong magnetic field created by a superconducting magnet, so that a large force is applied to the moving mechanism. In particular, when measuring a large sample, it is necessary to use a fairly robust one.
本発明は、従来の磁化測定手段段は、上記したように諸点において問題を有するものであるところから、これらの問題のない磁気測定手段、すなわち、装置構造が簡単で大型の試料を測定することができ、移動機構を必要としない磁気測定手段を提供しようというものである。 In the present invention, since the conventional magnetization measuring means stage has problems in various points as described above, magnetic measuring means without these problems, that is, measuring a large sample with a simple apparatus structure. Therefore, it is intended to provide a magnetic measurement means that does not require a moving mechanism.
本発明者らにおいては、鋭意研究の結果、可動部分を持たず、装置の大型化を伴わずに、単純な構造のピックアップコイルを超伝導磁石磁場内に置き、該コイル内に測定試料を固定し、印加磁界を変化せしめるという簡単な手段を講ずることによって大型高性能永久磁石も含め、多様な試料を対象として磁化率を測定することができることを知見したものである。本発明は、この知見に基づいてなされたものであり、印加磁界を変化させることによって、ピックアップコイルに誘導起電力生じさせ、その誘導起電力を測定し、積分することによって試料の磁化率を求めるものである。すなわち、本発明の構成は以下（１）ないし（７）に記載の通りである。
（１） 超伝導磁石の作る磁場内に、合成樹脂等非磁性材料からなる中空パイプにコイルを巻回した構造のピックアップコイルを設定し、このピックアップコイル内に試料を配置すると共に、該磁場内でコイルと試料とが移動しないように固定して印加磁界を変化させ、試料を収容したピックアップコイルに誘導起電力を生じさせ、この誘導起電力から、試料の磁化率を求めることを特徴とする、磁化率測定方法。
（２） 該変化する印加磁界の波形として、頂点が丸く調製された変化波形であることを特徴とする、前記（１）項に記載の磁化率測定方法。
（３） 測定対象が永久磁石である、前記（１）または（２）項に記載の磁化率測定方法（４） 超伝導磁石を用いてなる、誘電起電力から磁化率を求める磁化率測定装置において、超伝導磁石の作る磁場内に、合成樹脂等非磁性材料からなる中空パイプにコイルを巻回した構造のピックアップコイルを固定して配置する手段と、該コイル内に試料を固定して配置する手段と、印加磁界を変化させる手段と、印加磁界の変化によってピックアップコイルに生じた誘導起電力を測定する手段と、測定された誘導起電力から磁気率を求める演算手段とを備えてなることを特徴とする、磁化率測定装置。
（５） 該印加磁界変化手段として、頂点を丸くした変化波形を調製し、発生させる機能を備えた手段であることを特徴とする、前記（４）項に記載する磁化率測定装置。
（６） 該磁化率測定装置が温度調節機構を備えていることを特徴とする、前記（４）または（５）項に記載する磁化率測定装置。
（７） 測定対象が永久磁石である、前記（４）ないし（６）の何れか１項に記載の磁化率測定装置。
As a result of diligent research, the inventors of the present invention have a simple structure of a pickup coil in a superconducting magnet magnetic field without moving parts and without increasing the size of the apparatus, and a measurement sample is fixed in the coil. It has been found that the magnetic susceptibility can be measured for various samples including large-sized high-performance permanent magnets by taking a simple means of changing the applied magnetic field. The present invention has been made on the basis of this finding. An induced electromotive force is generated in a pickup coil by changing an applied magnetic field, the induced electromotive force is measured, and the magnetic susceptibility of the sample is obtained by integration. Is. That is, the configuration of the present invention is as described in (1) to (7) below.
(1) A pickup coil having a structure in which a coil is wound around a hollow pipe made of a non-magnetic material such as a synthetic resin is set in a magnetic field created by a superconducting magnet, a sample is placed in the pickup coil, The coil and the sample are fixed so as not to move, the applied magnetic field is changed, an induced electromotive force is generated in the pickup coil containing the sample, and the magnetic susceptibility of the sample is obtained from the induced electromotive force. , Magnetic susceptibility measurement method.
(2) The magnetic susceptibility measurement method according to (1), wherein the waveform of the changing applied magnetic field is a change waveform with a rounded top.
(3) The magnetic susceptibility measuring method according to (1) or (2) above, wherein the object to be measured is a permanent magnet. In the magnetic field generated by the superconducting magnet, means for fixing and arranging a pickup coil having a structure in which a coil is wound around a hollow pipe made of a non-magnetic material such as synthetic resin, and fixing and arranging a sample in the coil Means for changing the applied magnetic field, means for measuring the induced electromotive force generated in the pickup coil due to the change of the applied magnetic field, and calculating means for obtaining the magnetic modulus from the measured induced electromotive force. Magnetic susceptibility measuring device characterized by the above.
(5) The magnetic susceptibility measuring apparatus according to (4), wherein the applied magnetic field changing means is a means having a function of preparing and generating a change waveform with a rounded vertex.
(6) The magnetic susceptibility measuring device according to (4) or (5), wherein the magnetic susceptibility measuring device includes a temperature adjustment mechanism.
(7) The magnetic susceptibility measuring apparatus according to any one of (4) to (6), wherein the measurement target is a permanent magnet.
本発明は超伝導磁石を利用した永久磁石の測定法であり、強磁界が必要とされる高性能磁石の測定に適している。特に、従来の方法では困難であった大型の高性能永久磁石の測定が容易にできるようになったことは特筆に価する。さらに述べると、従来は、永久磁石は大型のものを作成したのちに所定の大きさに、切断して磁化率を測定し、出荷商品とされるが、本発明によって、大型試料を切断することなく、そのままでも検査することができ、効率があがる。また、ＮＭＲなど大型のままで使用するケースもあり、本発明は、それを容易に検査できることにより商品の信頼性が向上する。さらにまた、本発明は、測定に際しては、試料を可動させる必要はなく、そのため測定手段は、極めて簡素、単純でありコスト的に有利である。しかも、前述したように従来は、大型の永久磁石を測定する場合には、試料に強い力が加わることを考慮すると、本発明は、この点でも有利である。 The present invention is a method for measuring a permanent magnet using a superconducting magnet, and is suitable for measuring a high-performance magnet that requires a strong magnetic field. In particular, it is worthy of special mention that it has become possible to easily measure a large-sized high-performance permanent magnet, which was difficult with the conventional method. More specifically, in the past, after creating a large permanent magnet, the permanent magnet was cut into a predetermined size and the magnetic susceptibility was measured. It can be inspected as it is, increasing efficiency. In addition, there are cases in which NMR is used as it is, such as NMR, and the present invention improves the reliability of the product by being able to easily inspect it. Furthermore, according to the present invention, it is not necessary to move the sample at the time of measurement. Therefore, the measurement means is extremely simple and simple, and is advantageous in terms of cost. In addition, as described above, the present invention is advantageous also in this point in view of the fact that a large force is applied to the sample when measuring a large permanent magnet.
以下、本発明の最良の形態を実施例および図面に基づいて詳しく説明する。 Hereinafter, the best mode of the present invention will be described in detail based on examples and drawings.
図１は、本発明の磁化率測定装置であり、図２-1は、ピックアップコイルと試料を並べて示した図であり、図２-2は、ピックアップコイルの構成を示す図である。図３は、ピックアップコイル・試料を固定する治具を示す。図４は、印加磁界の波形を示し、図４-1は、頂点が丸まった本発明の一態様である印加磁界波形を示す図であり、図４-2は、その元になる三角波形である。図５は、実施例１で印加された磁界波形サイクルを示す図であり、図６はこの印加磁界の変化によって発生した誘導電圧曲線である。ただし、このときはピックアップコイル中に試料が存在する。さらに、図７は、図６の誘導電圧を時間で積分したもの（∫Vdt）と図５の印加磁界との関係を示している。同様の測定、計算を試料の無い場合にも行い、それを図７で示す試料のある場合の∫Vdtから差し引いたものが図８である。この図８の曲線をプラスの飽和値とマイナスの飽和値が等しくなるように軸を移動することによって補正し、さらにコイル定数、試料の体積で割ることにより∫Vdtを磁化に変換する。またさらに後述する方法で反磁界補正を行うことによりＪ−Ｈ履歴曲線を得ることができる。図９は、実施例１で求められたＮｄＦｅＢ系磁石のＪ−Ｈ履歴曲線である。図１０は、実施例１で求められたＮｉの磁化曲線である。そして、図１１は、実施例２のＮｄＦｅＢ系磁石のＪ−Ｈ履歴曲線を示すものである。 FIG. 1 is a magnetic susceptibility measuring apparatus according to the present invention, FIG. 2-1 is a diagram showing a pickup coil and a sample arranged side by side, and FIG. 2-2 is a diagram showing a configuration of the pickup coil. FIG. 3 shows a jig for fixing a pickup coil / sample. FIG. 4 shows the waveform of the applied magnetic field, FIG. 4-1 shows the applied magnetic field waveform that is one aspect of the present invention with rounded vertices, and FIG. 4-2 shows the original triangular waveform. is there. FIG. 5 is a diagram showing a magnetic field waveform cycle applied in Example 1, and FIG. 6 is an induced voltage curve generated by the change of the applied magnetic field. However, at this time, a sample exists in the pickup coil. Further, FIG. 7 shows the relationship between the induced voltage of FIG. 6 integrated over time (∫Vdt) and the applied magnetic field of FIG. FIG. 8 shows the same measurement and calculation performed in the absence of the sample, which is subtracted from ∫Vdt in the case of the sample shown in FIG. The curve of FIG. 8 is corrected by moving the axis so that the positive saturation value and the negative saturation value are equal, and further, the voltage Vdt is converted into magnetization by dividing by the coil constant and the volume of the sample. Furthermore, a JH history curve can be obtained by performing demagnetizing field correction by a method described later. FIG. 9 is a JH history curve of the NdFeB magnet obtained in Example 1. FIG. 10 is a magnetization curve of Ni obtained in Example 1. FIG. 11 shows a JH history curve of the NdFeB magnet of Example 2.
本発明の磁化率測定方法を実施する装置は、図１に示すように、超伝導磁石と、超伝導磁石の作る磁場内に、合成樹脂等非磁性材料からなる中空パイプにコイルを巻回した構造のピックアップコイルを固定して配置する手段と、該コイル内に試料を固定して配置する手段と、印加磁界を変化させる手段と、印加磁界の変化によってピックアップコイルに生じた誘導起電力を測定する手段と、測定された誘導起電力から磁化を求める演算手段とを備えている。 As shown in FIG. 1, the apparatus for carrying out the magnetic susceptibility measurement method of the present invention has a coil wound around a superconducting magnet and a hollow pipe made of a nonmagnetic material such as a synthetic resin in a magnetic field created by the superconducting magnet. A means for fixing and arranging a pickup coil having a structure, a means for fixing and arranging a sample in the coil, a means for changing an applied magnetic field, and an induced electromotive force generated in the pickup coil due to a change in the applied magnetic field And means for calculating magnetization from the measured induced electromotive force.
さらに、本発明の装置は、図面には示していないが、該印加磁界変化手段として、磁界の変化波形が三角波形のように直線が交差する態様の頂点を有する波形ではなく、頂点が丸く調整された変化波形を発生する磁界波形調節機能を備えている。さらにまた、任意の温度で測定可能なように温度調節機能を備えているものである。印加磁界波形としては、図４-1に示す態様では、三角波の角を丸めたものを例示しているが、このような三角波に限定されない。角が丸い波形なら特に制限はなく例えばサイン波でもよい。 Further, the apparatus of the present invention is not shown in the drawing, but the applied magnetic field changing means is not a waveform having an apex in which a straight line intersects like a triangular waveform, but the apex is adjusted to be round. The magnetic field waveform adjustment function for generating the changed waveform is provided. Furthermore, a temperature adjustment function is provided so that measurement can be performed at an arbitrary temperature. As an applied magnetic field waveform, in the embodiment shown in FIG. 4A, a waveform obtained by rounding the corners of a triangular wave is illustrated, but the applied magnetic field waveform is not limited to such a triangular wave. If the waveform has rounded corners, there is no particular limitation. For example, a sine wave may be used.
測定は、試料を設定した場合の磁界の変化によって生じる、ピックアップコイルの誘導起電力の測定と、試料を設定しないときの誘導起電力の測定の、少なくとも２回の測定からなり、これを基本とするものであり、前者の測定結果と後者の測定結果との差異から、Ｊ−Ｈ履歴曲線を求めることができる。その場合の基礎となる磁気モーメントＭは、下記数式１に基づき、これを演算することによって求められる。 The measurement consists of at least two measurements, the measurement of the induced electromotive force of the pickup coil caused by the change of the magnetic field when the sample is set, and the measurement of the induced electromotive force when the sample is not set. Therefore, a JH history curve can be obtained from the difference between the former measurement result and the latter measurement result. The magnetic moment M serving as a basis in that case is obtained by calculating this based on the following Equation 1.
式中、Ｖはピックアップコイルの誘導起電力、Ｍｏは初期磁化である。また、Ｃはピックアップコイルのコイル定数で、下記数式２により求められる。 In the formula, V is an induced electromotive force of the pickup coil, and Mo is an initial magnetization. C is a coil constant of the pickup coil, and is obtained by the following mathematical formula 2.
ただし、ｎ、Ｌ、Ｒはそれぞれ、単位長さあたりの巻き数、コイルの長さの２分の１、コイルの半径である。以下の実施例１で設定したピックアップコイルの定数Ｃの値は、２９４３（１／ｍ）であった。磁気モーメントを試料の体積で割ることにより体積磁化が求められる。また印加磁界は超伝導磁石に流れる電流値を測定することによって求めることができる。図９は、以上の測定方法によって求められた試料のＪ−Ｈ履歴曲線である。 Here, n, L, and R are the number of turns per unit length, half the length of the coil, and the radius of the coil, respectively. The value of the constant C of the pickup coil set in Example 1 below was 2943 (1 / m). Volume magnetization is determined by dividing the magnetic moment by the volume of the sample. The applied magnetic field can be obtained by measuring the value of the current flowing through the superconducting magnet. FIG. 9 is a JH history curve of the sample obtained by the above measurement method.
以下、本発明を具体的に実施例に基づいて説明する。ただし、これらの実施例は、あくまでも本発明を容易に理解し易くするための一助として開示するためのものであって、本発明を限定する趣旨ではない。 Hereinafter, the present invention will be specifically described based on examples. However, these examples are intended to be disclosed as an aid for facilitating the understanding of the present invention, and are not intended to limit the present invention.
実施例１；
磁化率測定試料として、サイズが４９．５×４９．４×５２．３ｍｍの六面体、重量が９４６ｇのＮｄＦｅＢ系永久磁石を準備した。測定に使用するピックアップコイルは、外径８０．２ｍｍのアクリルパイプに直径０．２３ｍｍのエナメル線を３５２回巻いて作成した。なお、ここでは、アクリルパイプを使用したが、非磁性材料であればよく、ガラスや非磁性金属でもよい。コイルの長さは８８．５ｍｍであった。準備した試料と、ピックアップコイルをスケールと共に図２に示す。これらの試料とピックアップコイルは、所定の間隔で平行に配置された三枚の円盤と円盤を固定保持する３本の立設支柱とからなる治具の最下段の円盤上に固定した。図３は、治具の概観を示す図である。なお、これらの治具の材質については、非磁性を示し、十分な強度を有し、温度変化のないものがよい。例えば、耐熱性アクリル樹脂、ベークライト樹脂等耐熱性に優れた合成樹脂、ガラス、セラミックス、非磁性金属等が挙げられる。
Example 1;
As a magnetic susceptibility measurement sample, an NdFeB permanent magnet having a size of 49.5 × 49.4 × 52.3 mm and a weight of 946 g was prepared. The pickup coil used for the measurement was prepared by winding an enameled wire having a diameter of 0.23 mm 352 times around an acrylic pipe having an outer diameter of 80.2 mm. Although an acrylic pipe is used here, any nonmagnetic material may be used, and glass or nonmagnetic metal may be used. The length of the coil was 88.5 mm. FIG. 2 shows the prepared sample and the pickup coil together with the scale. These samples and the pickup coil were fixed on a lowermost disk of a jig composed of three disks arranged in parallel at a predetermined interval and three standing columns for fixing and holding the disk. FIG. 3 is a diagram showing an overview of the jig. The material of these jigs is preferably non-magnetic, has sufficient strength, and does not change in temperature. Examples thereof include synthetic resins having excellent heat resistance such as heat-resistant acrylic resins and bakelite resins, glass, ceramics, and nonmagnetic metals.
準備した永久磁石試料を、ピックアップコイル中心に試料がくるように該治具に固定し、治具ごと無冷媒超伝導磁石に入れ、磁場中心に試料がくるように固定した。０．００２Ｔ／ｓｅｃの掃引速度で印加磁界をプラス７Ｔとマイナス７Ｔの間を往復させ、ピックアップコイルに生じる電圧を測定した。このとき印加磁界の波形は図４-2のような三角波でなく図４-1のように頂点が丸くなるように調製し、設定した。これは頂点の部分が計算上の特異点になることを防ぐためである。 The prepared permanent magnet sample was fixed to the jig so that the sample came to the center of the pickup coil, and the jig was put together with the non-refrigerant superconducting magnet, and fixed so that the sample came to the center of the magnetic field. The applied magnetic field was reciprocated between plus 7T and minus 7T at a sweep rate of 0.002 T / sec, and the voltage generated in the pickup coil was measured. At this time, the waveform of the applied magnetic field was prepared and set so that the apex was rounded as shown in FIG. 4-1, not the triangular wave as shown in FIG. This is to prevent the vertex portion from becoming a singular point in calculation.
前示条件の下で前記永久磁石を測定した結果、印加された磁界は、図５に示すサイクルで変化する波形の磁界が印加された。この印加磁界によってピックアップコイルに発生した誘導起電力は図６に示すとおりであった。図６の誘導電圧を時間で積分したものを縦軸に、図５の供給磁界を横軸にグラフを描くと図７が求められる。同様の測定、計算を試料が無い場合も行い、これを図７から差し引くと図８に示す結果が導き出された。プラスの飽和値とマイナスの飽和値は絶対値が等しいと考えられるので、そのように軸をずらすことによって補正した。こうすることによって、初期磁化Ｍｏを無視することができる。これをコイル定数と体積で割り算することにより磁化に変換し、さらに反磁場補正を行ったものが図９である。 As a result of measuring the permanent magnet under the preceding conditions, a magnetic field having a waveform that changes in a cycle shown in FIG. 5 was applied. The induced electromotive force generated in the pickup coil by this applied magnetic field was as shown in FIG. FIG. 7 is obtained by plotting the induced voltage of FIG. 6 integrated over time on the vertical axis and the supplied magnetic field of FIG. 5 on the horizontal axis. Similar measurements and calculations were performed in the absence of the sample, and when this was subtracted from FIG. 7, the result shown in FIG. 8 was derived. The positive saturation value and the negative saturation value are considered to have the same absolute value, and thus corrected by shifting the axis. By doing so, the initial magnetization Mo can be ignored. FIG. 9 shows the result obtained by dividing this by the coil constant and the volume to convert to magnetization and further performing demagnetizing field correction.
この場合の反磁界の補正は、試料と同じ形状のニッケルを測定し、その磁化曲線の傾きから求めた反磁界係数を用いて行った。すなわち、反磁界係数は試料の形状によって決まる定数であり、回転楕円体のような特殊な形状のものを除き、それ以外の形状のものは複雑なため計算で求めることが困難である。このような場合、ニッケルを用いて同様の形状の試料を作成し、係数を求めることができる。その求め方は、従前のパルス磁石を用いる方法の場合と同様であり、前掲非特許文献２に詳しく記載されている。
求められたニッケルの磁化曲線は、図１０の通りであった。この図において、立ち上がりの直線部分の傾きの逆数が反磁界係数で、この図から０．２６６と求められた。
In this case, the demagnetizing field was corrected by measuring nickel having the same shape as the sample and using the demagnetizing coefficient obtained from the inclination of the magnetization curve. That is, the demagnetizing factor is a constant determined by the shape of the sample, and except for special shapes such as a spheroid, other shapes are complicated and difficult to obtain by calculation. In such a case, a sample having the same shape can be prepared using nickel, and the coefficient can be obtained. The method for obtaining it is the same as in the case of the conventional method using a pulse magnet, and is described in detail in Non-Patent Document 2 described above.
The obtained magnetization curve of nickel was as shown in FIG. In this figure, the reciprocal of the slope of the rising straight line portion is the demagnetizing factor, which was found to be 0.266 from this figure.
図９のＪ−Ｈ履歴曲線から実施例１の永久磁石試料は、Ｊs＝１．３９（Ｔ）、Ｂｒ＝１．３６（Ｔ）、ＨｃＪ＝１．００（ＭＡ／ｍ）、ＨｃＢ＝０．９２（Ｔ）、ＢＨmax＝３５９（ｋＪ／ｍ３）によって特徴づけられる特性を有する磁石であることが明らかとなった。 From the JH history curve of FIG. 9, the permanent magnet sample of Example 1 has J s = 1.39 (T), Br = 1.36 (T), HcJ = 1.00 (MA / m), HcB = It was revealed that the magnet had characteristics characterized by 0.92 (T), BH max = 359 (kJ / m 3 ).
実施例２；
磁化率測定試料として、サイズが２３．５×２３．５×２５．０ｍｍの六面体、重量が１０４．０１ｇのＮｄＦｅＢ系永久磁石を実施例１と同様の方法で測定した。ピックアップコイルは外径３９．７８ｍｍのアクリルパイプに直径０．２３ｍｍのエナメル線を１８１回巻いて作成した。コイルの長さは４４．８８ｍｍであった。コイル定数はＣ＝３０１０（１／ｍ）であった。図１１にＪ−Ｈ履歴曲線を示す。これからＪｓ＝１．４０（Ｔ）、Ｂｒ＝１．３７（Ｔ）、ＨｃＪ＝１．０２（ＭＡ／ｍ）、ＨｃＢ＝０．９５（Ｔ）、ＢＨｍａｘ＝３５９（ｋＪ／ｍ３）と求められた。
Example 2;
As a magnetic susceptibility measurement sample, a NdFeB permanent magnet having a size of 23.5 × 23.5 × 25.0 mm and a weight of 104.01 g was measured in the same manner as in Example 1. The pickup coil was prepared by winding an enameled wire having a diameter of 0.23 mm 181 times around an acrylic pipe having an outer diameter of 39.78 mm. The length of the coil was 44.88 mm. The coil constant was C = 3010 (1 / m). FIG. 11 shows a JH history curve. From this, Js = 1.40 (T), Br = 1.37 (T), HcJ = 1.02 (MA / m), HcB = 0.95 (T), BHmax = 359 (kJ / m 3 ). It was.
実施例３；
実施例２のピックアップコイルを用い、７７．５０ｇの４Ｎニッケルの磁化曲線を測定した。飽和磁化は学術文献（例えば、前掲非特許文献５参照のこと）に記載された値０．６１６Ｔとほぼ一致した。
Example 3;
Using the pickup coil of Example 2, the magnetization curve of 77.50 g of 4N nickel was measured. The saturation magnetization almost coincided with the value 0.616T described in academic literature (for example, see Non-Patent Document 5 above).
以上、本発明は、実施例にも具体的に記載したように大型で高性能永久磁石の磁化率をきわめて簡単に測定することができる手段を提供するのに成功したものであり、その意義は、磁石の開発がますます大型化、高性能化する傾向にありことを考慮すると、コストのかからない測定手段を提供する点で磁石の開発に大いに寄与することが期待される。 As described above, the present invention has succeeded in providing a means capable of measuring the magnetic susceptibility of a large, high-performance permanent magnet very easily, as specifically described in the examples. Considering that the development of magnets tends to increase in size and performance, it is expected to greatly contribute to the development of magnets in terms of providing a measurement means that does not cost much.
本発明の磁化率測定手段は、従来法では、大型高性能の永久磁石を測定しようとすると、測定装置手段は必然的に大がかりな設計とせざるを得ないものであったが、既存の測定装置、測定手段を利用し、これに極めて簡単な測定手段・測定システムを適用ないし付加することによって、十分に対処しえることが明らかにされたものであり、その意義はきわめて大きい。今後、磁化率測定手段として大いに利用され、主流をなすことが期待される。 In the conventional method, the magnetic susceptibility measuring means of the present invention inevitably had a large-scale design when measuring a large, high-performance permanent magnet. It has been clarified that it is possible to cope with the problem by applying or adding a very simple measuring means / measuring system to the measuring means. In the future, it will be used as a means of measuring magnetic susceptibility and expected to become mainstream.
Claims (7)
The magnetic susceptibility measuring device according to any one of claims 4 to 6, wherein the measurement object is a permanent magnet.
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