JP6819328B2 - Magnetic powder and its manufacturing method - Google Patents
Magnetic powder and its manufacturing method Download PDFInfo
- Publication number
- JP6819328B2 JP6819328B2 JP2017019145A JP2017019145A JP6819328B2 JP 6819328 B2 JP6819328 B2 JP 6819328B2 JP 2017019145 A JP2017019145 A JP 2017019145A JP 2017019145 A JP2017019145 A JP 2017019145A JP 6819328 B2 JP6819328 B2 JP 6819328B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic powder
- core
- baked
- coercive force
- shell
- 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.)
- Active
Links
Landscapes
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
Description
本発明は、ネオジム系の磁性粉およびその製造方法に関する。 The present invention relates to a neodymium-based magnetic powder and a method for producing the same.
磁性粉の磁気特性を向上させるために、その粒径を小さくすることが求められている。磁性粉をサブミクロンオーダー程度以下に微粒子化するために、特許文献１，２に示すように、共沈等の湿式法を用いて磁性粉を製造することが提案されている。 In order to improve the magnetic properties of the magnetic powder, it is required to reduce its particle size. As shown in Patent Documents 1 and 2, it has been proposed to produce a magnetic powder by using a wet method such as coprecipitation in order to make the magnetic powder finer than about submicron order.
特許文献１、２に記載されているように、共沈等の湿式法では、磁性粉を構成するネオジム（Ｎｄ）等の成分元素を含む金属酸化物を合成し、これをカルシウム（Ｃａ）化合物を用いて還元することによって、磁石に変化させる。還元後の磁石に残存するＣａ種は、還元後の磁石をそのまま水に浸漬して洗浄することによって除去される。Ｃａ種に含まれるＣａ金属が洗浄の際に水と反応すると、水素が発生し、磁石と反応して、磁性粉の保磁力が低下する。保磁力は、磁化された磁性体を磁化されていない状態に戻すために必要な反対向きの外部磁場の強さを示し、永久磁石では、保磁力が高いことが望ましい。 As described in Patent Documents 1 and 2, in a wet method such as coprecipitation, a metal oxide containing a component element such as neodymium (Nd) constituting a magnetic powder is synthesized, and this is combined with a calcium (Ca) compound. It is transformed into a magnet by reducing it with. The Ca species remaining on the reduced magnet is removed by immersing the reduced magnet in water as it is and washing it. When the Ca metal contained in the Ca species reacts with water during cleaning, hydrogen is generated and reacts with the magnet to reduce the coercive force of the magnetic powder. The coercive force indicates the strength of the external magnetic field in the opposite direction required to return the magnetized magnetic material to the unmagnetized state, and it is desirable that the permanent magnet has a high coercive force.
上記に鑑み、本発明者らは、保磁力が高い磁性粉およびその製造方法を提供することを目的とする。 In view of the above, the present inventors aim to provide a magnetic powder having a high coercive force and a method for producing the same.
本発明は、Ｎｄ２Ｆｅ１４-ｘＣｏｘＢ（０≦ｘ≦１４）で表される結晶体粒子からなるコアと、前記コアの表面に形成されたＮｄ金属を含むシェルとを有する磁性粉を提供する。 The present invention, magnetic powder and a shell comprising a core consisting of crystal grains represented by Nd 2 Fe 14-x Co x B (0 ≦ x ≦ 14), a Nd metal formed on the surface of the core I will provide a.
本発明の磁性粉によれば、結晶体粒子からなるコアは、その表面に形成されたＮｄ金属を含むシェルによって保護されている。水素等の反応性の高いガスは、シェルに含まれるＮｄ金属と優先的に反応し、コアを構成する結晶体粒子との反応は抑制され、磁性粉の保磁力の低下が抑制できる。すなわち、本発明によれば、保磁力が高い磁性粉を提供することができる。 According to the magnetic powder of the present invention, the core composed of crystalline particles is protected by a shell containing Nd metal formed on the surface thereof. The highly reactive gas such as hydrogen reacts preferentially with the Nd metal contained in the shell, the reaction with the crystalline particles constituting the core is suppressed, and the decrease in the coercive force of the magnetic powder can be suppressed. That is, according to the present invention, it is possible to provide a magnetic powder having a high coercive force.
また、本発明は、上記の磁性粉の製造方法を提供する。本発明の磁性粉の製造方法は、前記コアの成分元素を含む金属化合物を熱処理して、前記コアの前駆体と、前記コアの表面に形成された前記シェルの前駆体とを有する焼成体を製造する焼成工程と、前記焼成体をＣａ化合物を用いて還元する還元工程と、前記還元工程後の該焼成体に残存するＣａ種を水酸化カルシウム（Ｃａ（ＯＨ）２）に変化させて除去する除去工程とを含む。 The present invention also provides the above method for producing a magnetic powder. Method of manufacturing a magnetic powder of the present invention, by heat-treating a metal compound containing a constituent element of the core, a precursor of the core, baked formed body having a precursor of the shell formed on the surface of the core and baked formation process of manufacturing, and reduction step of reducing the Firing body using a Ca compound, a Ca species remaining in the calcination body after the reduction step the calcium hydroxide (Ca (OH) 2) Includes a removal step of varying and removing.
本発明の磁性粉の製造方法によれば、焼成工程が終了した時点の焼成体において、磁性粉のコアの前駆体と、コアの前駆体の表面に形成されたシェルの前駆体とを含むコアシェル構造が構成されている。このため、後続の還元工程でコアとシェルが生成し、除去工程において、コアがシェルに保護される。また、除去工程では、焼成体に残存するＣａ種をＣａ（ＯＨ）２に変化させて除去するため、Ｃａ金属が洗浄の際に水と反応して水素が発生することを防ぐことができる。永久磁石に対して高い反応性を有する水素ガスの発生が抑制された状態でＣａ種を除去することができるため、保磁力が高い磁性粉を製造することができる。 According to the manufacturing method of the magnetic powder of the present invention, the baked formed body at the time when baked forming step is completed, the precursor of the core of the magnetic powder, and a precursor of the shell formed on the surface of the core of the precursor The core shell structure including is configured. Therefore, the core and the shell are generated in the subsequent reduction step, and the core is protected by the shell in the removal step. Further, in the removing step, for removing by changing the Ca species remaining in baked adult body Ca (OH) 2, it is possible to prevent the Ca metal hydrogen is generated reacts with water during cleaning .. Since Ca species can be removed in a state where the generation of hydrogen gas having high reactivity with permanent magnets is suppressed, magnetic powder having a high coercive force can be produced.
（磁性粉）
本発明の磁性粉は、図１に示すように、Ｎｄ２Ｆｅ１４-ｘＣｏｘＢ（０≦ｘ≦１４）で表されるネオジム系の結晶体粒子からなるコア１２と、コア１２の表面に形成されたＮｄ金属を含むシェル１１とを有するコアシェル構造の磁性粉１である。シェル１１は、コア１２の表面の一部または全部を覆うように形成されている。磁性粉に対する各組成の原子組成百分率は、Ｎｄ：１５ａｔ％〜２５ａｔ％、Ｆｅ：６０ａｔ％〜８０ａｔ％、Ｃｏ：０ａｔ％〜１５ａｔ％、Ｂ：３ａｔ％〜９ａｔ％であることが好ましく、Ｎｄ：１７ａｔ％〜２４ａｔ％、Ｆｅ：６５ａｔ％〜７９ａｔ％、Ｃｏ：０ａｔ％〜１４ａｔ％、Ｂ：３ａｔ％〜７ａｔ％であることが特に好ましい。このような組成比であれば、コアシェル構造を安定に得ることができ、より高い保磁力を得ることができる。
(Magnetic powder)
As shown in FIG. 1, the magnetic powder of the present invention has a core 12 composed of neodymium-based crystal particles represented by Nd 2 Fe 14-x Co x B (0 ≦ x ≦ 14), and the surface of the core 12. It is a magnetic powder 1 having a core-shell structure having a shell 11 containing an Nd metal formed in. The shell 11 is formed so as to cover a part or all of the surface of the core 12. The atomic composition percentage of each composition with respect to the magnetic powder is preferably Nd: 15 at% to 25 at%, Fe: 60 at% to 80 at%, Co: 0 at% to 15 at%, B: 3 at% to 9 at%, and Nd: It is particularly preferably 17 at% to 24 at%, Fe: 65 at% to 79 at%, Co: 0 at% to 14 at%, and B: 3 at% to 7 at%. With such a composition ratio, a core-shell structure can be stably obtained, and a higher coercive force can be obtained.
コアの結晶体粒子の直径は、１０ｎｍ〜１０００ｎｍであることが好ましい。このような微細な結晶体粒子は、反応性が高く、そのままでは水素や酸素と結合して磁気特性が損なわれ易い。本発明では、永久磁石として機能する結晶体粒子からなるコアがシェルによって保護されているため、磁気特性に優れ、安定性の高い磁性粉を得ることができる。 The diameter of the crystal particles of the core is preferably 10 nm to 1000 nm. Such fine crystalline particles are highly reactive and, as they are, easily combine with hydrogen or oxygen to impair their magnetic properties. In the present invention, since the core made of crystalline particles functioning as a permanent magnet is protected by the shell, it is possible to obtain a magnetic powder having excellent magnetic properties and high stability.
（磁性粉の製造方法）
本発明の磁性粉は、コアの成分元素であるＮｄ元素、Ｆｅ元素またはＣｏ元素、Ｂ元素を含む金属化合物を熱処理して焼成体を得て、この焼成体について還元、不純物除去を行うことによって製造することができる。本発明の磁性粉は、コアの成分元素を含む金属化合物を熱処理した時点で、コアシェル構造を有していることが好ましい。すなわち、熱処理後の焼成体は、コアの前駆体と、コアの表面に形成されたシェルの前駆体とを有していることが好ましい。
(Manufacturing method of magnetic powder)
Magnetic powder of the present invention, Nd element is a component element of the core, Fe element or Co element, to obtain a baked formed body by heat-treating a metal compound containing the element B, performs reduction, impurities removed for the baked adult body Can be manufactured by. The magnetic powder of the present invention preferably has a core-shell structure when a metal compound containing a component element of the core is heat-treated. That is, baked formed body after the heat treatment, it is preferable to have a precursor of the core, and a precursor of a shell formed on the surface of the core.
磁性粉を微粉化するためには、湿式法で磁石の成分元素を含む金属化合物を合成することが好ましい。湿式法を用いて、上記のコアシェル構造を安定に得られる磁石の成分元素の組成比で金属化合物を作製し、熱処理して焼成させることによって、その直径が１０ｎｍ〜１０００ｎｍである微細なコアシェル構造を有する磁性粉を製造することができる。本発明の磁性粉は、コアの成分元素を含む金属化合物を熱処理した時点で、コアシェル構造を有するようにできるため、直径が１０ｎｍ〜１０００ｎｍである微細な磁性粉においても、容易にコアシェル構造を形成させることができる。 To fine powder of the magnetic powder, it is preferable to synthesize the metal compound containing a constituent element of the magnet by a wet method. By a wet method to prepare a metal compound in the composition ratio of constituent elements of the magnet obtained stably above core-shell structure, by tempering formed by heat-treating a fine core-shell structure that the diameter is 10nm~1000nm It is possible to produce a magnetic powder having the above. Since the magnetic powder of the present invention can have a core-shell structure when the metal compound containing the component element of the core is heat-treated, the core-shell structure can be easily formed even in a fine magnetic powder having a diameter of 10 nm to 1000 nm. Can be made to.
コアの成分元素を含む金属化合物は、コアの成分元素が導入されたブロックコポリマーであることが特に好ましい。このような金属化合物は、コアの成分元素（Ｎｄ，Ｆｅ，Ｃｏ，Ｂ）の有機金属錯体をブロックコポリマーに選択的に導入することによって合成することができる。ブロックコポリマーの自己組織化構造を利用することによって、高濃度のコアの成分元素を均一に分散させることができる。また、この金属化合物を熱処理すれば、比較的低い温度（８００℃程度）でコアの前駆体を結晶化させてコアに変化させることができるため、副生成物の生成が抑制され、コアを高純度の結晶体粒子として得ることができる。 The metal compound containing the component element of the core is particularly preferably a block copolymer in which the component element of the core is introduced. Such metal compounds can be synthesized by selectively introducing an organometallic complex of core component elements (Nd, Fe, Co, B) into the block copolymer. By utilizing the self-assembled structure of the block copolymer, a high concentration of the constituent elements of the core can be uniformly dispersed. Further, if this metal compound is heat-treated, the precursor of the core can be crystallized at a relatively low temperature (about 800 ° C.) and changed into a core, so that the formation of by-products is suppressed and the core becomes high. It can be obtained as pure crystalline particles.
コアの成分元素が導入されたブロックコポリマーは、例えば、国際公開第２０１３／０３９２１６号に記載の方法によって製造することができる。ブロックコポリマーとしては、ポリスチレン−ポリメチルメタクリレート（ＰＳ−ｂ−ＰＭＭＡ）、ポリスチレン−ポリエチレンオキシド（ＰＳ−ｂ−ＰＥＯ）、ポリスチレン−ポリビニルピリジン（ＰＳ−ｂ−ＰＶＰ）、ポリスチレン−ポリフェロセニルジメチルシラン（ＰＳ−ｂ−ＰＦＳ）、ポリイソプレン−ポリエチレンオキシド（ＰＩ−ｂ−ＰＥＯ）、ポリブタジエン−ポリエチレンオキシド（ＰＢ−ｂ−ＰＥＯ）、ポリエチルエチレン−ポリエチレンオキシド（ＰＥＥ−ｂ−ＰＥＯ）、ポリブタジエン−ポリビニルピリジン（ＰＢ−ｂ−ＰＶＰ）、ポリイソプレン−ポリメチルメタクリレート（ＰＩ−ｂ−ＰＭＭＡ）、ポリスチレン−ポリアクリル酸（ＰＳ−ｂ−ＰＡＡ）、ポリブタジエン−ポリメチルメタクリレート（ＰＢ−ｂ−ＰＭＭＡ）等が挙げられる。ポリマーブロック成分の極性の差が大きいほど導入する前駆体も極性の差が大きいものを用いることができるため、それぞれのポリマーブロック成分に前駆体を導入し易くなるという観点から、ＰＳ−ｂ−ＰＶＰ、ＰＳ−ｂ−ＰＥＯ、ＰＳ−ｂ−ＰＡＡ等が特に好ましい。また、有機金属錯体としては、コアの成分元素のアセチルアセトナート錯体、カルボニル錯体、ジオネート錯体等を好適に用いることができる。 The block copolymer into which the component elements of the core have been introduced can be produced, for example, by the method described in International Publication No. 2013/0392216. Examples of the block copolymer include polystyrene-polymethyl methacrylate (PS-b-PMMA), polystyrene-polyethylene oxide (PS-b-PEO), polystyrene-polypolypyridine (PS-b-PVP), and polystyrene-polyferrocenyldimethylsilane (PS-b-PVP). PS-b-PFS), polyisoprene-polystyrene oxide (PI-b-PEO), polybutadiene-polystyrene oxide (PB-b-PEO), polyethylethylene-polystyrene oxide (PEE-b-PEO), polybutadiene-polystyrenepyridine (PB-b-PVP), polyisoprene-polymethylmethacrylate (PI-b-PMMA), polystyrene-polyacrylic acid (PS-b-PAA), polybutadiene-polymethylmethacrylate (PB-b-PMMA) and the like. Be done. The larger the difference in polarity of the polymer block components, the larger the difference in polarity can be used for the precursor. Therefore, from the viewpoint of facilitating the introduction of the precursor into each polymer block component, PS-b-PVP , PS-b-PEO, PS-b-PAA and the like are particularly preferable. Further, as the organometallic complex, an acetylacetonate complex, a carbonyl complex, a dionate complex or the like, which are component elements of the core, can be preferably used.
金属化合物が有機成分を含む場合には、焼成体についてさらに大気中で熱処理を行う等によって、炭素成分を除去する工程を行うことが好ましい。この工程によって、焼成体は酸化されるため、その後、還元工程を行うことが好ましい。還元工程は、Ｃａ化合物を用いて行うことが好ましい。具体的には、還元工程では、ＣａＨ２等のＣａ化合物と焼成体の粉末とを混合して、減圧雰囲気下または不活性ガス雰囲気下で熱処理を行うことが好ましい。 If the metal compound comprises an organic component, such as by performing a heat treatment at more atmosphere for baked adult body, it is preferable to perform the step of removing the carbon component. This step for baked adult body is oxidized, then it is preferable to carry out the reduction step. The reduction step is preferably carried out using a Ca compound. More specifically, in the reduction step, by mixing the powder of Ca compound and baked formed body such as CaH 2, heat treatment is preferably performed under a reduced pressure atmosphere or an inert gas atmosphere.
焼成体をＣａ化合物を用いて還元する還元工程を行った後に、Ｃａ化合物に由来するＣａ種を除去する除去工程を行うことが好ましい。除去工程は、コアを構成する結晶体粒子に対して高い反応性を有する物質（例えば、水素、酸素等）をできるだけ除去した環境下で行うことが好ましい。例えば、還元工程後の焼成体に残存するＣａ金属と水が反応することによって生成する。このため、焼成体を水蒸気と接触させて、Ｃａ種をＣａ（ＯＨ）２に変化させることによって、水素とコアとの反応を防ぐことができる。また、除去工程は、水等の洗浄液に不溶性のＣａ化合物（例えば、炭酸カルシウム：ＣａＣＯ３）が生成されない環境下、すなわち、二酸化炭素：ＣＯ２等をできるだけ除去した環境下で行うことが好ましい。例えば、ＣＯ２を吸着する物質（例えば、Ｃａ（ＯＨ）２）を設置した密閉系で除去工程を行うことによって、ＣＯ２濃度が低い環境下で除去工程を行うことができ、水に不溶であるＣａＣＯ３が焼成体に付着することを抑制することができる。除去工程において、コアを構成する結晶体粒子に対して高い反応性を有する物質や、Ｃａ種等と反応して不純物となり得る物質が生成することを抑制することによって、本発明に係るコアシェル構造を有する磁性粉の保磁力をより顕著に向上させることができる。 The baked formed body after the reduction step of reduction with Ca compound, it is preferable to perform the removal step of removing the Ca species derived from the Ca compound. The removal step is preferably performed in an environment in which substances having high reactivity (for example, hydrogen, oxygen, etc.) with respect to the crystal particles constituting the core are removed as much as possible. For example, Ca metal and water remaining in the baked formed body after the reduction step is produced by reacting. Therefore, the baked adult body in contact with steam, by changing the Ca species Ca (OH) 2, it is possible to prevent the reaction between hydrogen and the core. Further, the removal step is preferably performed in an environment in which a Ca compound (for example, calcium carbonate: CaCO 3 ) insoluble in a cleaning solution such as water is not generated, that is, in an environment in which carbon dioxide: CO 2 and the like are removed as much as possible. For example, by performing the removal step in a closed system in which a substance that adsorbs CO 2 (for example, Ca (OH) 2 ) is installed, the removal step can be performed in an environment where the CO 2 concentration is low, and it is insoluble in water. can there CaCO 3 is suppressed from adhering to the baked adult body. The core-shell structure according to the present invention is formed by suppressing the formation of a substance having high reactivity with crystalline particles constituting the core or a substance that can become an impurity by reacting with Ca species or the like in the removing step. The coercive force of the magnetic powder contained can be improved more remarkably.
以下に説明する製造方法によって磁性粉を製造し、試料１〜１７として、成分元素の存在比と、保磁力と、磁化とを測定した。試料１〜１７は、それぞれ、表１に示す原料添加率（ａｔ％）で原料を混合した以外は、同様の方法で製造したため、各工程について一括して説明する。 Magnetic powder was produced by the production method described below, and the abundance ratio of component elements, coercive force, and magnetization were measured as samples 1 to 17. Since the samples 1 to 17 were produced by the same method except that the raw materials were mixed at the raw material addition rate (at%) shown in Table 1, each step will be described collectively.
（磁性粉の製造方法）
（焼成工程）
ブロックコポリマーとして、ポリスチレン−ｂ−２−ビニルピリジン 分子量ＭｍＰＳ：Ｍｎ２ＶＰ＝１０２００：９７０００（以下、ＰＳ２ＶＰ（１０２：９７）と略す）のトルエン溶液を作製した。このトルエン溶液に、コアの成分元素（Ｎｄ，Ｆｅ，Ｃｏ，Ｂ）を含む化合物、すなわち、アセチルアセトナートネオジム：Ｎｄ（ａｃａｃ）３・６Ｈ２Ｏ、１，１−ビス（４，４，５，５−テトラメチル−１，３，２−ジオキサボロラン−２−リル）フェロセン, アセチルアセトナート鉄：Ｆｅ（ａｃａｃ）３、トリス（２，２，６，６−テトラメチル−３，５−ヘプタンジオナト）コバルト（ＩＩＩ）をそれぞれ表１に示す原料添加率になるように加えて、２時間攪拌した。その後、トルエンを蒸発させ試料を乾燥させた。
(Manufacturing method of magnetic powder)
(Baked formation process)
As a block copolymer, a toluene solution of polystyrene-b-2-vinylpyridine molecular weight Mm PS : Mn 2VP = 10200: 97000 (hereinafter abbreviated as PS2VP (102: 97)) was prepared. This toluene solution, a compound containing constituent elements of the core (Nd, Fe, Co, B), i.e., acetylacetonate neodymium: Nd (acac) 3 · 6H 2 O, 1,1- bis (4,4,5 , 5-Tetramethyl-1,3,2-dioxaborolan-2-lyl) Ferrocene, Acetylacetonate Iron: Fe (acac) 3 , Tris (2,2,6,6-tetramethyl-3,5-heptanionato) Cobalt (III) was added so as to have the raw material addition rates shown in Table 1, and the mixture was stirred for 2 hours. Then, toluene was evaporated and the sample was dried.
次に、錯体分解やポリマーの自己組織化を促進するために、Ｎ２気流下において、９０℃で６時間処理した後に１８０℃で３時間処理し、その後、３５０℃で６時間処理し、アニールを行った。その後、試料中の炭素分を完全に除去するため、大気中で、８００℃で６時間、酸化熱処理し、焼成体を得た。 Next, in order to promote self-organization of complex decomposition or polymers, in N 2 under a stream for 3 hours at 180 ° C. after treatment for 6 hours at 90 ° C., then for 6 hours at 350 ° C., annealing Was done. Thereafter, in order to completely remove the carbon content in the sample, in air for 6 hours at 800 ° C., and oxidizing heat treatment, to obtain a baked adult body.
（還元工程）
グローブボックス中で、焼成体０．１ｇを１．２当量のＣａＨ２（０．０８ｇ）と混合した。熱処理前に炉内を減圧し系中の酸素を除去した。Ａｒ気流下で、８００℃まで１時間で昇温し、３時間保持後、引き続き減圧下で８００℃で３時間熱処理した。
(Reduction process)
In a glove box, and mixed with a baked adult body 0.1 g 1.2 eq CaH 2 (0.08g). Before the heat treatment, the pressure inside the furnace was reduced to remove oxygen in the system. The temperature was raised to 800 ° C. in 1 hour under an Ar stream, held for 3 hours, and then heat-treated at 800 ° C. for 3 hours under reduced pressure.
（除去工程）
ＣＯ２を捕獲するために、グローブボックス内にシャーレに入れた１００ｇのＣａ（ＯＨ）２を設置した。同様の目的でインキュベータ内にもシャーレに入れた３０ｇのＣａ（ＯＨ）２を設置した。インキュベータ内で還元工程後の焼成体を水蒸気と室温で２４時間反応させた。
(Removal process)
In order to capture CO 2 , 100 g of Ca (OH) 2 in a petri dish was placed in the glove box. For the same purpose, 30 g of Ca (OH) 2 in a petri dish was installed in the incubator. The baked formed body after the reduction step in an incubator and allowed to react for 24 hours at steam and room temperature.
次に、焼成体を洗浄した。第１洗浄工程として、粉末状の焼成体を３００ｍＬのテフロン（登録商標）製のビーカーに移し、５０ｍＬの蒸留水を加えた。ビーカー内の焼成体を手で揺らすことで回しながら、超音波洗浄機に１分かけて、Ｃａ（ＯＨ）２を溶解させた。磁石をビーカーの裏側から接触させて焼成体を引付け、２ｍＬのスポイトで上澄み液を吸い出した。上澄み液を除去後、第１洗浄工程を再度繰り返した。 Then, to wash the baked adult body. As a first cleaning step, the powdery baked formed body was transferred to a Teflon beaker of 300 mL, was added distilled water 50 mL. Rotate by rocking by hand baked adult body beaker over a period of 1 minute in an ultrasonic washer, to dissolve the Ca (OH) 2. Attracts baked formed body is brought into contact with a magnet from the back side of the beaker, the supernatant liquid was siphoned off using a dropper of 2 mL. After removing the supernatant, the first washing step was repeated again.
第２洗浄工程として、蒸留水１０ｍＬを加え焼成体をスポイトで吸い取りスクリュー管に移した。水の量が５ｍＬ程度の状態で揺らしながら超音波洗浄機に３０秒かけた。スクリュー管の底に磁石を接触させて焼成体を引き付け、白濁した上澄み液を除いた。第２洗浄工程を水が殆ど濁らなくなるまで繰り返した後、スクリュー管の底に磁石を接触させて焼成体を引き付け、上澄み液を除去した後で、スクリュー管に蓋をした。その後、真空容器にスクリュー管を設置し、蓋を緩めた状態で真空引きし、焼成体を乾燥させることによって、磁性粉を製造した。 A second cleaning step, the distilled water 10mL was added Firing body was transferred to a screw tube blotting using a dropper. The ultrasonic cleaner was used for 30 seconds while shaking with the amount of water being about 5 mL. Bottom contacting the magnet screw tube attracts baked adult body, excluding the turbid supernatant. After repeating the second washing step until no more water cloudy almost attract baked formed body is brought into contact with the magnet to the bottom of the screw tube, after removing the supernatant was capped screw tube. Thereafter, the screw tube was placed in a vacuum chamber, evacuating and in a loosened condition the lid, by drying the baked adult body to produce a magnetic powder.
（分析）
試料１〜２０について、プラズマ発光分析装置（ＩＣＰ）による磁性粉中の組成（ａｔ％）と、保磁力Ｈｃｊ（ｋＯｅ）と、磁化σ１８ｋＯｅ（ｅｍｕ／ｇ）とを測定し、表１に示した。保磁力Ｈｃｊと磁化σ１８ｋＯｅについては、除去工程の前後の値を併記した。また、保磁力の維持率（％）＝（除去工程後の保磁力／除去工程前の保磁力）×１００を計算し、表１に併記した。
(analysis)
Samples 1 to 20, the composition of the magnetic powder by plasma emission spectrometer (ICP) and (at%), the coercive force H cj (kOe), were measured with magnetization σ 18kOe (emu / g), in Table 1 Indicated. For the coercive force H cj and the magnetization σ 18 kOe , the values before and after the removal step are shown together. Further, the coercive force retention rate (%) = (coercive force after the removal step / coercive force before the removal step) × 100 was calculated and is also shown in Table 1.
（比較例）
比較例１〜３として、特許文献１に係る磁性粉について、原料添加率（ａｔ％）とＣａ種の除去工程後の保磁力（ｋＯｅ）および磁化（ｅｍｕ／ｇ）とを表２に示した。表２における比較例１〜３は、それぞれ特許文献１の実施例１〜３に対応し、特許文献１から算出した値をそれぞれ示している。
(Comparison example)
As Comparative Examples 1 to 3, Table 2 shows the raw material addition rate (at%) and the coercive force (koe) and magnetization (emu / g) after the removal step of Ca species for the magnetic powder according to Patent Document 1. .. Comparative Examples 1 to 3 in Table 2 correspond to Examples 1 to 3 of Patent Document 1, respectively, and show values calculated from Patent Document 1, respectively.
また、比較例４，５として、表３に示す原料添加率（ａｔ％）で原料を混合した以外は、実施例と同様の方法で磁性粉を製造した。比較例４，５については、ＩＣＰによる磁性粉中の組成（ａｔ％）と、除去工程の前後の保磁力Ｈｃｊ（ｋＯｅ）と、磁化σ１８ｋＯｅ（ｅｍｕ／ｇ）の測定値と、保磁力の維持率（％）とを表３に併記した。 Further, as Comparative Examples 4 and 5, magnetic powder was produced by the same method as in Examples except that the raw materials were mixed at the raw material addition rate (at%) shown in Table 3. Comparative Examples 4 and 5, the composition of the magnetic powder in accordance with ICP and (at%), and the front and rear of the coercive force H cj removal step (kOe), and the measured values of magnetization σ 18kOe (emu / g), the coercive force The maintenance rate (%) of is also shown in Table 3.
表１に示すように、実施例に係る試料１〜１７の磁性粉は保磁力が高く、除去工程後においても６．２ｋＯｅ〜９．０ｋＯｅであった。これに対し、表２に示すように、比較例１〜５の磁性粉の保磁力は、１．８〜２．８ｋＯｅであり、実施例の磁性粉と比較して著しく低い。また、比較例４，５の磁性粉の保磁力については、除去工程前では実施例の磁性粉と同程度であるが、除去工程後に比較例１〜３の磁性粉と同程度まで低下しており、実施例の磁性粉と比較して保磁力の維持率が低かった。実施例の磁性粉は、比較例の磁性粉と比較して保磁力が著しく高く、除去工程前後の保磁力維持率が高い。特に、試料３，９，１２，１３，１５〜１７については、磁化σ１８ｋＯｅも１００ｅｍｕ／ｇ以上であり、従来の磁性粉と同等またはそれ以上であった。磁石では保磁力と磁化はトレードオフの関係にあるが、試料３，９，１２，１３，１５〜１７については、磁化を低下させることなく保磁力を向上させることができた。また、試料１〜１７では、除去工程前後の保磁力の維持率が７９％以上と高かった。 As shown in Table 1, the magnetic powders of Samples 1 to 17 according to Examples had a high coercive force and were 6.2 kOe to 9.0 kOe even after the removal step. On the other hand, as shown in Table 2, the coercive force of the magnetic powders of Comparative Examples 1 to 5 is 1.8 to 2.8 kOe, which is significantly lower than that of the magnetic powders of Examples. The coercive force of the magnetic powders of Comparative Examples 4 and 5 was about the same as that of the magnetic powders of Examples before the removal step, but decreased to the same level as the magnetic powders of Comparative Examples 1 to 3 after the removal step. Therefore, the maintenance rate of the coercive force was lower than that of the magnetic powder of the example. The magnetic powder of the example has a remarkably high coercive force as compared with the magnetic powder of the comparative example, and has a high coercive force retention rate before and after the removal step. In particular, for samples 3, 9, 12, 13 , 15 to 17, the magnetization σ 18 kOe was 100 emu / g or more, which was equal to or higher than that of the conventional magnetic powder. In magnets, there is a trade-off between coercive force and magnetization, but for samples 3, 9, 12, 13, 15 to 17, the coercive force could be improved without lowering the magnetization. Further, in the samples 1 to 17, the maintenance rate of the coercive force before and after the removal step was as high as 79% or more.
表２に示すように、比較例１〜５では、磁性粉中のＮｄの割合が１４．３ａｔ％以下であるのに対し、表１に示すように、試料１〜１７では、磁性粉中のＮｄの割合は、１６．６ａｔ％〜２３．４ａｔ％であり、比較例１〜５よりもＮｄの割合が多かった。実施例では、磁性粉中のＮｄの割合は、１５ａｔ％以上であるのに対し、比較例１〜５では、磁性粉中のＮｄの割合が１５ａｔ％未満と少なく、コアシェル構造が形成されていないため、保磁力の低下を十分に抑制できていないと考えられる。特に、特許文献１に記載されているように、比較例１〜３では、ＣＯ２やＨ２が発生することを抑制することなく焼成体を１０Ｌの水中に投入してＣａ種の除去工程を行っているため、除去工程中に水素が激しく発生して磁性粉と反応し、保磁力が特に低くなったと推定できる。 As shown in Table 2, in Comparative Examples 1 to 5, the ratio of Nd in the magnetic powder was 14.3 at% or less, whereas in Samples 1 to 17, the ratio in the magnetic powder was 14.3 at% or less. The ratio of Nd was 16.6 at% to 23.4 at%, and the ratio of Nd was higher than that of Comparative Examples 1 to 5. In the examples, the ratio of Nd in the magnetic powder is 15 at% or more, whereas in Comparative Examples 1 to 5, the ratio of Nd in the magnetic powder is as small as less than 15 at%, and the core-shell structure is not formed. Therefore, it is considered that the decrease in coercive force cannot be sufficiently suppressed. In particular, as described in Patent Document 1, Comparative Example 1 to 3, CO 2 or H 2 is a baked formed body was put into water of 10L without suppressing the occurrence Ca species removal process It can be presumed that hydrogen was violently generated during the removal process and reacted with the magnetic powder, resulting in a particularly low coercive force.
また、試料４について、ＳＴＥＭ（Scanning Transmission Electron Microscope）像および元素分析マッピングを行った結果を図２Ａ〜図３Ｂに示す。図２Ｂおよび図３Ｂに示す比較的明るい箇所は、コア１２を示しており、比較的暗い箇所は、シェル１１を示している。図２Ａ〜図３Ｂに示すように、実施例に係る磁性粉は、図１に模式的に示すようなコアシェル構造を有していることがわかった。実施例の磁性粉では、ネオジム磁石の結晶体粒子からなるコアは、その表面に形成されたＮｄ金属を含むシェルによって保護されている。このため、水素等の反応性の高いガスは、シェルに含まれるＮｄ金属と優先的に反応し、コアを構成する結晶体粒子との反応は抑制され、その結果、磁性粉の保磁力の低下が抑制できたと考えられる。また、実施例では、除去工程においてＣＯ２やＨ２と反応することを抑制したため、磁性粉の保磁力の低下が抑制できたと考えられる。これに対して比較例１〜３の磁性粉では、Ｎｄの含有量が少ないため、コアシェル構造が形成されず、さらには、除去工程においてＣＯ２との反応やＨ２の発生を抑制しなかったため、コアを構成する結晶体粒子が水素ガス等と反応し易く、保磁力が低くなったと考えられる。また、図２Ａに示すＳＴＥＭ像から磁性粉の直径を測定したところ、１０ｎｍ〜１０００ｎｍであった。実施例に示すように、コアの成分元素が導入されたブロックコポリマーを用いて湿式で製造することによって、直径が１０ｎｍ〜１０００ｎｍである微細な磁性粉においても、コアシェル構造を形成させることができた。 Further, the results of STEM (Scanning Transmission Electron Microscope) image and elemental analysis mapping of the sample 4 are shown in FIGS. 2A to 3B. The relatively bright areas shown in FIGS. 2B and 3B indicate the core 12, and the relatively dark areas indicate the shell 11. As shown in FIGS. 2A to 3B, it was found that the magnetic powder according to the example had a core-shell structure as schematically shown in FIG. In the magnetic powder of the example, the core composed of crystalline particles of the neodymium magnet is protected by a shell containing Nd metal formed on the surface thereof. Therefore, a highly reactive gas such as hydrogen reacts preferentially with the Nd metal contained in the shell, and the reaction with the crystalline particles constituting the core is suppressed, and as a result, the coercive force of the magnetic powder is lowered. Is considered to have been suppressed. Further, in the examples, it is considered that the decrease in the coercive force of the magnetic powder could be suppressed because the reaction with CO 2 and H 2 was suppressed in the removing step. On the other hand, in the magnetic powders of Comparative Examples 1 to 3, the core-shell structure was not formed because the content of Nd was small, and further, the reaction with CO 2 and the generation of H 2 were not suppressed in the removal step. It is considered that the crystalline particles constituting the core easily react with hydrogen gas and the like, and the coercive force is lowered. Moreover, when the diameter of the magnetic powder was measured from the STEM image shown in FIG. 2A, it was 10 nm to 1000 nm. As shown in the examples, the core-shell structure could be formed even in a fine magnetic powder having a diameter of 10 nm to 1000 nm by performing wet production using a block copolymer in which a core component element was introduced. ..
１ 磁性粉
１１ シェル
１２ コア
1 Magnetic powder 11 shell 12 core
Claims (4)
該コアの表面に形成されたＮｄ金属からなるシェルとを有する磁性粉。 A core consisting of crystal grains represented by Nd 2 Fe 14-x Co x B (0 ≦ x ≦ 14),
Magnetic powder and a shell consisting of Nd metal formed on the surface of the core.
前記焼成体をＣａ化合物を用いて還元する還元工程と、
前記還元工程後の該焼成体に残存するＣａ種をＣａ（ＯＨ）２に変化させて除去する除去工程とを含む請求項２に記載の磁性粉の製造方法。 By heat-treating a metal compound composed of a block copolymer component element of the core is introduced, to produce a precursor of the core, the baked adult having a precursor of the shell formed on the surface of the core baked The process and
A reducing step of reducing with the Firing body Ca compound,
Method for producing magnetic powder according to claim 2 including a removal step of removing Ca species remaining in the calcination body after the reduction step is varied to Ca (OH) 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017019145A JP6819328B2 (en) | 2017-02-03 | 2017-02-03 | Magnetic powder and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017019145A JP6819328B2 (en) | 2017-02-03 | 2017-02-03 | Magnetic powder and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2018123414A JP2018123414A (en) | 2018-08-09 |
| JP6819328B2 true JP6819328B2 (en) | 2021-01-27 |
Family
ID=63111011
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2017019145A Active JP6819328B2 (en) | 2017-02-03 | 2017-02-03 | Magnetic powder and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6819328B2 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04345002A (en) * | 1991-05-22 | 1992-12-01 | Kawasaki Steel Corp | Manufacture of rare earth magnet |
| JP3865180B2 (en) * | 1998-09-18 | 2007-01-10 | 愛知製鋼株式会社 | Heat-resistant rare earth alloy anisotropic magnet powder |
| JP4371188B2 (en) * | 2000-08-22 | 2009-11-25 | 信越化学工業株式会社 | High specific electric resistance rare earth magnet and method for manufacturing the same |
| JP2013149664A (en) * | 2012-01-17 | 2013-08-01 | Showa Denko Kk | Method for manufacturing alloy for rare earth-transition metal-boron-based magnet |
| JP6432406B2 (en) * | 2014-03-27 | 2018-12-05 | 日立金属株式会社 | R-T-B system alloy powder and R-T-B system sintered magnet |
-
2017
- 2017-02-03 JP JP2017019145A patent/JP6819328B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2018123414A (en) | 2018-08-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112342029B (en) | Biological heavy metal contaminated soil remediation agent and preparation method and application thereof | |
| US8795546B2 (en) | Magnetic ceramic and process for production thereof | |
| WO2010131686A1 (en) | Scorodite-type iron-arsenic compound particles, production method, and arsenic-containing solid | |
| JP6980207B2 (en) | Rare earth iron nitrogen-based magnetic powder and its manufacturing method | |
| JPH0359980B2 (en) | ||
| JP6845491B2 (en) | Samarium-iron-nitrogen magnet powder and its manufacturing method | |
| WO2018096733A1 (en) | Rare earth-iron-nitrogen system magnetic powder and method for producing same | |
| KR102521570B1 (en) | Lithium ion adsorbent and a method for recovering lithium ion using the same | |
| Clendenning et al. | Magnetic ceramic films from a metallopolymer resist using reactive ion etching in a secondary magnetic field | |
| JP2018090892A (en) | Rare-earth-iron-nitrogen-based magnetic powder and method for producing the same | |
| CN111937095A (en) | Samarium-iron-nitrogen-based magnet powder and method for producing same, and samarium-iron-nitrogen-based magnet and method for producing same | |
| JP2008091873A (en) | Rare-earth-iron-nitrogen based magnetic powder, and method for manufacturing the same | |
| Sun et al. | Morphology-controlled synthesis of α-FeOOH and its derivatives | |
| JP6759855B2 (en) | Method for manufacturing rare earth-iron-nitrogen alloy powder | |
| JP6819328B2 (en) | Magnetic powder and its manufacturing method | |
| CN114349006A (en) | Surface modification method of MXene material | |
| CN110970187B (en) | Samarium-iron-bismuth-nitrogen system magnet powder and samarium-iron-bismuth-nitrogen system sintered magnet | |
| JP5435416B2 (en) | Magnetic powder and method for producing magnetic powder | |
| JP6601432B2 (en) | Manufacturing method of magnetic powder | |
| JP2020057779A (en) | Samarium-iron-bismuth-nitrogen-based magnet powder and samarium-iron-bismuth-nitrogen-based sintered magnet | |
| JP2014129202A (en) | Method for manufacturing layered double hydroxide | |
| KR101135446B1 (en) | Manufacturing method of hollow spheral iron oxide particles | |
| JP2010270379A (en) | Method for producing rare-earth-iron-nitrogen-based magnet powder | |
| US20230144902A1 (en) | Samarium-iron-nitrogen based magnet and samarium-iron-nitrogen based magnet powder | |
| JP2005187311A (en) | Method of producing perovskite compound oxide and precursor substance used in the method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20191004 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20200730 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20201006 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20201027 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20201201 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20201214 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6819328 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |