JP4336786B2 - Method for producing ferromagnetic metal powder - Google Patents
Method for producing ferromagnetic metal powder Download PDFInfo
- Publication number
- JP4336786B2 JP4336786B2 JP2005124882A JP2005124882A JP4336786B2 JP 4336786 B2 JP4336786 B2 JP 4336786B2 JP 2005124882 A JP2005124882 A JP 2005124882A JP 2005124882 A JP2005124882 A JP 2005124882A JP 4336786 B2 JP4336786 B2 JP 4336786B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- water
- rare earth
- elements
- magnetic
- 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.)
- Expired - Lifetime
Links
Description
本発明は，磁気テープや磁気ディスク等の磁気記録媒体の磁性層を構成するのに好適な強磁性金属粉末の製造法に関する。 The present invention relates to a method for producing a ferromagnetic metal powder suitable for forming a magnetic layer of a magnetic recording medium such as a magnetic tape or a magnetic disk.
オーディオ用，ビデオ用，コンピュータ用などの磁気テープやディスク等の磁気記録媒体は，記録容量の高密度化による小型化，高性能化がより一段と進み，それに伴って磁気記録媒体用の磁性粉も，従来の酸化鉄系統のものから保磁力・飽和磁化の高い金属磁性粉末へと進展してきている。 Magnetic recording media such as audio, video, and computer magnetic tapes and disks are becoming smaller and higher performance due to higher recording capacities, and magnetic powders for magnetic recording media are also becoming available. , The conventional iron oxide series has progressed to metal magnetic powder with high coercive force and saturation magnetization.
このような用途に使用される金属磁性粉は鉄を主成分とするものが代表的であるが，Ｎi,Ｃo等を主成分とするものもある。 The metal magnetic powder used for such applications is typically composed mainly of iron, but there are also those composed mainly of Ni, Co and the like.
鉄系磁性粉は，工業的にはオキシ水酸化鉄もしくは酸化鉄を主体とした針状粉末の表面にＳi,Ａl,Ｚr,Ｃa等の焼結防止剤を付着又は吸着させた後，加熱還元する方法によって製造されているのが一般である。 Iron-based magnetic powders are industrially reduced by heat reduction after adhering or adsorbing sintering inhibitors such as Si, Al, Zr, and Ca on the surface of needle-shaped powders mainly composed of iron oxyhydroxide or iron oxide. In general, it is manufactured by a method.
オキシ水酸化鉄もしくは酸化鉄を主体とする化合物を工業的に合成するにあたっては，中和剤としてコストや取り扱いの容易さから周期律表第１ａ族元素化合物，例えばＮａＯＨ，Ｎａ2ＣＯ3，ＫＯＨ等が使用されてきた。このため，金属磁性粉の表面にはＮa やＫ等の周期律表第１ａ族元素が多少とも不可避的不純物として残存する結果となっている。 When industrially synthesizing a compound mainly composed of iron oxyhydroxide or iron oxide, the group 1a element compound of the periodic table such as NaOH, Na 2 CO 3 , KOH is used as a neutralizing agent because of cost and ease of handling. Etc. have been used. For this reason, the result is that some elements of Group 1a of the periodic table such as Na and K remain as inevitable impurities on the surface of the metal magnetic powder.
周期律表第２ａ族元素についても同様なことが言える。例えば特公昭５９ ３２８８２
号公報や特開平２−１０７７０１号公報に記載されているように，当該元素は焼結防止剤等として使用されることがあり，このため，金属磁性粉の表面に残存する結果となっている。
The same can be said for the Group 2a element of the periodic table. For example, Japanese Patent Publication No. 59 32882
As described in Japanese Patent Laid-Open No. 2-107701 and Japanese Patent Laid-Open No. 2-107701, the element may be used as a sintering inhibitor or the like, and as a result, remains on the surface of the metal magnetic powder. .
本発明は，金属磁性粉末を用いた高密度磁気記録媒体の一層の品質改善を目的としたもので，磁気特性及び分散性が良く，また磁気層の保存安定性の優れた強磁性金属粉末を得ることを目的としたものである。 The present invention aims to further improve the quality of a high-density magnetic recording medium using a metal magnetic powder. A ferromagnetic metal powder having good magnetic properties and dispersibility and excellent storage stability of a magnetic layer. The purpose is to obtain.
本発明によれば，周期律表第１ａ族元素の含有量が0.05重量％以下であり，必要に応じて金属元素の総量に対して 0.1〜３０原子％のアルミニウム, 更には金属元素の総量に対して 0.1〜１０原子％の希土類元素（Ｙを含む）を含有させ，また可溶性となる周期律表第２ａ族元素の残存量が0.1 重量％以下の針状の強磁性金属粉末を提供する。この針状の強磁性金属粉末を製造するには，Ａｌ含有オキシ水酸化鉄を２５０〜４００℃で加熱してＡｌをＡｌ2Ｏ3 として固定したうえ，これに希土類元素（Ｙを含む）を含有させ，得られたＡｌと希土類元素（Ｙを含む）を含む酸化鉄の粉末を還元性雰囲気中で加熱還元する段階と，ＡｌをＡｌ2Ｏ3 として固定したあと希土類元素（Ｙを含む）を含有させる前に水洗を行う段階とを経るのが良い。 According to the present invention, the content of the Group 1a element in the periodic table is 0.05% by weight or less, and if necessary, 0.1 to 30 atomic% of aluminum, and further to the total amount of metal elements, based on the total amount of metal elements. On the other hand, there is provided an acicular ferromagnetic metal powder containing 0.1 to 10 atomic% of a rare earth element (including Y) and having a remaining amount of Group 2a element of the periodic table that is soluble in 0.1 wt% or less. In order to manufacture this acicular ferromagnetic metal powder, Al-containing iron oxyhydroxide is heated at 250 to 400 ° C. to fix Al as Al 2 O 3 , and a rare earth element (including Y) is added thereto. The step of heating and reducing the iron oxide powder containing Al and rare earth elements (including Y) obtained in a reducing atmosphere, and fixing the Al as Al 2 O 3 and then rare earth elements (including Y) It is preferable to go through a step of washing with water before containing.
金属磁性粉末は，前記のように周期律表第１ａ族の元素，例えばＬi,Ｎa,Ｋ等や，周期律表第２ａ族の元素，例えばＭg,Ｃa,Ｓr,Ｂa等が粒子表面に付着しているが, このような塩基性元素の可溶性塩が粒子表面に存在すると塗布型媒体を形成する場合の分散性を劣化させ, 更に媒体製品の保存安定性や耐候性を劣化させることがわかった。また，周期律表第１ａ族の元素は還元時の焼結を促進する作用もある。 As described above, the metal magnetic powder has a periodic table group 1a element such as Li, Na, K, etc., and a periodic table group 2a element such as Mg, Ca, Sr, Ba, etc. attached to the particle surface. However, it can be seen that the presence of such a soluble salt of a basic element on the particle surface deteriorates the dispersibility when forming a coating-type medium, and further deteriorates the storage stability and weather resistance of the medium product. It was. In addition, elements of group 1a of the periodic table also have an action of promoting sintering during reduction.
近年の磁気記録媒体の高密度化により金属磁性粉の微粒子化が進んでいることから，還元時の焼結がより起こり易くなるとともに表面積の増加により，これら第１ａ族元素および第２ａ族元素の含有量も増加する傾向にある。 Due to the recent trend toward finer magnetic magnetic powders due to higher recording density of magnetic recording media, sintering during reduction is more likely to occur and the surface area increases, so that these Group 1a elements and Group 2a elements The content also tends to increase.
したがって，金属磁性粉の表面にこれら元素が残留していると，これが原因で次のような結果を招くことがわかった。 Therefore, it was found that if these elements remain on the surface of the metal magnetic powder, this causes the following results.
（Ａ）樹脂の吸着が弱くなりテープの耐久性が低下する。
（Ｂ）可溶性であるためテープ保存時に樹脂中の塩素と化合して塩化物となり，または水酸化物としてテープ表面に析出し，ドロップアウトの増加などを招来してテープ特性の低下を招く。
（Ｃ）還元時の焼結防止が不十分となり，粒子間の焼結，針状性のくずれによりＨｃ，ＳＦＤ，配向特性の低下を招く。
（Ｄ）塩基性のこれらの元素の存在によりテープ化の際に潤滑剤となる脂肪酸等が吸着して摩擦係数が高くなる。
(A) Adsorption of the resin is weakened and the durability of the tape is lowered.
(B) Since it is soluble, it combines with chlorine in the resin to form a chloride, or precipitates as a hydroxide on the surface of the tape when stored on the tape, leading to an increase in dropout and the like, resulting in a decrease in tape characteristics.
(C) Sintering prevention at the time of reduction becomes insufficient, and Hc, SFD, and orientation characteristics are deteriorated due to sintering between particles and loss of acicularity.
(D) Due to the presence of these basic elements, fatty acids and the like which become lubricants are adsorbed during tape formation, and the friction coefficient increases.
本発明者らは，従来から不可避の成分とされていた周期表第１ａ族元素を0.05重量％以下に低減するならば，前記のような問題は一掃できることを知見した。また焼結防止剤としては可溶性の第２ａ族元素に代えて，酸化物となって可溶性とならない元素すなわちアルミニウムおよび／または希土類元素（Ｙを含む）を選択して適量含有させれば, 微粒子化に伴う分散性, 保存安定性の低下を防止でき，また磁気特性も飛躍的に向上することを見い出した。 The present inventors have found that the above-mentioned problems can be eliminated if the Group 1a element of the periodic table, which has conventionally been considered as an inevitable component, is reduced to 0.05% by weight or less. In addition, as a sintering inhibitor, instead of the soluble group 2a element, an element that does not become an oxide and becomes insoluble, that is, aluminum and / or rare earth element (including Y) is selected and contained in an appropriate amount, so that it becomes fine particles. It was found that the dispersibility and storage stability associated with the increase in the magnetic properties could be prevented, and that the magnetic properties were dramatically improved.
周期表第１ａ族元素を0.05重量％以下にするには，これらの元素が製造過程で不可避的に混入する場合にはその除去処理を行なうことが必要である。この除去処理は金属磁性粉製造工程中に十分な洗浄工程を挿入することによって有利に行ない得る。例えば, 製造されたオキシ水酸化鉄粉，酸化鉄粉または金属磁性粉を十分に洗浄するのである。特にオキシ水酸化鉄, 酸化鉄, 金属磁性粉と工程が進むに伴って該元素は，粒子表面に偏析してくるので洗浄によって除去ができることになる。また洗浄水に温水や酸を加えてｐＨを下げた洗浄水を用いれば更に効率良く除去する事ができる。 In order to make the Group 1a elements of the periodic table 0.05% by weight or less, when these elements are inevitably mixed in during the production process, it is necessary to remove them. This removal treatment can be advantageously performed by inserting a sufficient washing step in the metal magnetic powder production process. For example, the produced iron oxyhydroxide powder, iron oxide powder or metal magnetic powder is thoroughly washed. In particular, as the process proceeds with iron oxyhydroxide, iron oxide, and metal magnetic powder, the element segregates on the particle surface and can be removed by washing. Further, it is possible to remove the water more efficiently by using washing water whose pH is lowered by adding warm water or acid to the washing water.
このような洗浄による周期律表第１ａ族元素の除去処理を行えば，周期律表第２ａ族元素の可溶性のものも併せて除去処理が行える。 If the removal process of the group 1a element of the periodic table by such cleaning is performed, the soluble element of the group 2a element of the periodic table can also be removed.
周期律表第１ａ族および第２ａ族の元素を含まない原料を使用することのほか前記のような除去処理を施すことによって、第１ａ族元素では０．０５重量％以下好ましくは０．０１重量％以下、また可溶性となる第２ａ族元素の含有量は０．１重量％以下、好ましくは０．０１重量％以下とすることができる。 In addition to using raw materials that do not contain elements of Group 1a and Group 2a of the Periodic Table, and performing the removal treatment as described above, 0.05% by weight or less, preferably 0.01% by weight of Group 1a elements. % Or less, and the content of the soluble Group 2a element can be 0.1% by weight or less , preferably 0.01% by weight or less.
これによって，金属磁性粉の前記Ａ〜Ｄの問題が回避できる。すなわち第１ａ族元素が0.05重量％を超えると，テープ化のさいに樹脂との相溶性が悪くなって分散できなかったり，磁気塗料化しても塗膜強度の低いものとなり，また可溶性であるためにテープ保存時にテープ表面に溶出して結晶性の化合物となるため，ドロップアウトの増加等の原因となりテープ保存安定が低下する。他方，可溶性となる第２ａ族元素が0.1 重量％を超えると, 樹脂との相溶性が悪くなって塗膜強度も低くなり, 極端に多くなると第１ａ族と同様にテープ保存安定性も悪くなる。 Thereby, the problems A to D of the metal magnetic powder can be avoided. That is, if the Group 1a element exceeds 0.05% by weight, the compatibility with the resin deteriorates during tape formation, and it cannot be dispersed. In addition, when it is stored on the tape, it dissolves on the surface of the tape and becomes a crystalline compound, which causes an increase in dropout and lowers the storage stability of the tape. On the other hand, if the soluble group 2a element exceeds 0.1% by weight, the compatibility with the resin deteriorates and the coating strength also decreases, and if it increases excessively, the storage stability of the tape also deteriorates like the group 1a. .
加えて本発明によれば，Ａlおよび／または希土類元素を適量含有させることにより，金属磁性粉の分散性が改善され且つ磁気特性の一層の向上を図ることができる。すなわち本発明によれば, 可溶性でかつ塩基性である周期律１ａ族元素および２ａ族元素を実質上含まず，アルミニウムおよび／または希土類元素を含有する分散性および磁気特性の優れた強磁性金属粉末を提供できる。 In addition, according to the present invention, by containing an appropriate amount of Al and / or rare earth elements, the dispersibility of the metal magnetic powder can be improved and the magnetic properties can be further improved. That is, according to the present invention, the ferromagnetic metal powder having excellent dispersibility and magnetic properties containing substantially no periodic 1a group element and 2a group element which is soluble and basic, and contains aluminum and / or rare earth elements. Can provide.
ここで，周期律表第１ａ族元素はＬｉ，Ｎａ，Ｋ等，周期律表第２ａ族元素はＭｇ，Ｃａ，Ｓｒ，Ｂａ等，希土類元素はＹ，Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｔｂ，Ｄｙ，Ｇｄ等を包含する。 Here, Group 1a elements of the periodic table are Li, Na, K, etc., Group 2a elements of the periodic table are Mg, Ca, Sr, Ba, etc., and rare earth elements are Y, La, Ce, Pr, Nd, Sm, Including Tb, Dy, Gd and the like.
本発明に従う金属磁性粉を製造するには，オキシ水酸化鉄または酸化鉄に所定量の希土類元素とＡlを含有させ，これを加熱還元する方法が好適である。被還元物のオキシ水酸化鉄ないし酸化鉄を主体として含む金属化合物粉末としては，α-FeOOH，γ-FeOOH，α-Fe2O3，γ-Fe2O3, Fe3O4およびこれらの中間型に相当するものの他，これらにＮi,Ｃo,Ｃr,Ｍn,Ｚn等の金属成分を含有したものが好適なものとして挙げられ，好ましくは針状性の良いものが使用される。 In order to produce the metal magnetic powder according to the present invention, a method in which a predetermined amount of rare earth element and Al are contained in iron oxyhydroxide or iron oxide and this is heated and reduced is suitable. Examples of metal compound powders mainly containing iron oxyhydroxide or iron oxide as the reductant include α-FeOOH, γ-FeOOH, α-Fe 2 O 3 , γ-Fe 2 O 3 , Fe 3 O 4 and these In addition to those corresponding to the intermediate type, those containing a metal component such as Ni, Co, Cr, Mn, Zn, etc. are preferred, and those having good acicularity are preferably used.
Ａlを含有させるのに使用できるＡl化合物としては, Ａl2(ＳＯ4)3，Ａl(ＮＯ3)3,ＡlＣｌ3などの水溶性塩, さらにはＮaＡlＯ2( アルミン酸ナトリウム) などの水可溶性アルミン酸塩などが挙げられ, これらのＡl化合物を被還元物の粒子表面に被着させるには, これらのＡl化合物をアルカリ水溶液中に溶解させ, この溶液中に被還元物粉末を分散させた後, 炭酸ガスを吹き込むか酸を添加して中和することによって行うことができ，これによって，結晶質ないし非晶質なＡl2Ｏ3・ｎＨ2Ｏ（含水・酸化アルミニウム）として粒子表面に被着される。 Al compounds that can be used to contain Al include water-soluble salts such as Al 2 (SO 4 ) 3 , Al (NO 3 ) 3 , and AlCl 3, and water-soluble aluminum such as NaAlO 2 (sodium aluminate). In order to deposit these Al compounds on the particle surface of the substance to be reduced, these Al compounds are dissolved in an alkaline aqueous solution, and the powder of the substance to be reduced is dispersed in this solution. This can be done by blowing carbon dioxide or adding acid to neutralize, so that the surface of the particles is coated as crystalline or amorphous Al 2 O 3 .nH 2 O (hydrous / aluminum oxide). Worn.
またＡlを該被還元物の粒子に固溶させる方法でも良い。α-FeOOHやγ-FeOOHにＡlを固溶させるには FeSO4やFeCl2等の第１鉄塩の水溶液をNaOH, Na2CO3, NH4OH 等の中和剤で中和した後に空気等により酸化してα-FeOOH, γ-FeOOH等を生成させる反応系に上記の水可溶性のＡl塩やアルミン酸塩を添加すれば良い。さらにα-Fe2O3にＡl固溶させるには Fe2(SO4)3, FeCl3 等の第２鉄塩の水溶液と NaOH, KOH等の中和剤を使用し, 水熱合成法によりα-Fe2O3を合成する反応系に上記の水可溶性のＡl塩やアルミン酸塩を添加すればよい。 Alternatively, Al may be dissolved in the particles of the substance to be reduced. To dissolve Al in α-FeOOH or γ-FeOOH After neutralizing an aqueous solution of ferrous salt such as FeSO 4 or FeCl 2 with a neutralizing agent such as NaOH, Na 2 CO 3 or NH 4 OH, air The above water-soluble Al salt or aluminate may be added to a reaction system that is oxidized by the above to produce α-FeOOH, γ-FeOOH, or the like. Furthermore, in order to dissolve Al in α-Fe 2 O 3 , an aqueous solution of ferric salt such as Fe 2 (SO 4 ) 3 and FeCl 3 and a neutralizing agent such as NaOH and KOH are used. The water-soluble Al salt or aluminate may be added to the reaction system for synthesizing α-Fe 2 O 3 .
こうして得られたＡｌ含有オキシ水酸化鉄ないし酸化鉄を２５０〜４００℃で加熱してＡｌをＡｌ2O3として固定したうえ、これを希土類元素を含有させる工程の原料として使用するのがよい。この時、オキシ水酸化鉄は該加熱時の脱水反応により酸化鉄に変成されている。希土類元素を含有させるには、希土類元素化合物含有液中に原料粒子を分散させ、水分を蒸発させる方法等が採用できる。 The Al-containing iron oxyhydroxide or iron oxide thus obtained is heated at 250 to 400 ° C. to fix Al as Al 2 O 3 , and this is preferably used as a raw material for the step of containing a rare earth element. At this time, iron oxyhydroxide is converted to iron oxide by a dehydration reaction during the heating. To a rare earth element, the raw material particles are dispersed in dilute earth element compound-containing liquid, a method to evaporate the moisture and the like can be employed.
上記の各種方法にて所定量のＡlと希土類元素を含有させた酸化鉄の粉末は，還元性雰囲気中で加熱する事により還元され, Ａlと希土類元素を含有する鉄を主成分とする金属磁性粉となる。加熱還元は被還元物の種類によって最適条件が異なるが，通常は水素気流中で３００〜７００℃の温度下で行うのが良い。 The iron oxide powder containing a predetermined amount of Al and rare earth elements by the various methods described above is reduced by heating in a reducing atmosphere, and the metal magnetism is mainly composed of iron containing Al and rare earth elements. It becomes powder. Although the optimum conditions for heat reduction vary depending on the type of the substance to be reduced, it is usually preferable to perform the reduction in a hydrogen stream at a temperature of 300 to 700 ° C.
なお，前述の製造過程において NaOH, KOH, Na2CO3, NH4OH 等の中和剤を使用する段階が存在し，かような中和剤から由来する周期律表第１ａ族元素が金属磁性粉に残存することになるが，前記したように，これら第１ａ族元素の残存は工程を経る毎の十分な洗浄処理によって有利に除去することができる。 In addition, there is a stage of using a neutralizing agent such as NaOH, KOH, Na 2 CO 3 , NH 4 OH or the like in the manufacturing process described above, and Group 1a element of the periodic table derived from such a neutralizing agent is a metal. Although it remains in the magnetic powder, as described above, the residue of these Group 1a elements can be advantageously removed by a sufficient cleaning process at each step.
こうして得られた金属磁気性粉の希土類元素の含有量は0.１〜１０原子％が適当であり，好ましくは0.2〜５原子％が良い。0.1原子％未満では, 希土類元素の効果が小さく,
加熱還元時に焼結し易くなる。他方，１０原子％を超えると希土類元素の酸化物の量が多くなって飽和磁化が小さくなり，磁性材料として不適当なものとなる。
The content of rare earth elements in the metal magnetic powder thus obtained is suitably 0.1 to 10 atomic%, preferably 0.2 to 5 atomic%. If it is less than 0.1 atomic%, the effect of rare earth elements is small,
It becomes easy to sinter at the time of heat reduction. On the other hand, if it exceeds 10 atomic%, the amount of rare earth oxide increases and the saturation magnetization decreases, making it unsuitable as a magnetic material.
またＡl含有量は 0.1〜３０原子％が適当であり，好ましくは１〜２０原子％が良い。0.１原子％未満では加熱還元時に焼結し易くなり, ３０原子％を超えると飽和磁化が小さくなってしまう。 The Al content is suitably from 0.1 to 30 atomic%, preferably from 1 to 20 atomic%. If it is less than 0.1 atomic%, it becomes easy to sinter at the time of heat reduction, and if it exceeds 30 atomic%, the saturation magnetization becomes small.
〔参考例１〕
Ｆeに対して５％のＣoを含む長軸長さが０．２μｍ、軸比１５のα−ＦｅＯＯＨを５０ｇ、４００℃にて３時間加熱してα−Ｆｅ2Ｏ3とした。このものを、純水５リットル中に懸濁させた後、濾過し、６０℃の純水にて水洗し、乾燥した。
[ Reference Example 1]
50 g of α-FeOOH having a major axis length of 0.2 μm and an axial ratio of 15 containing 5% Co with respect to Fe was heated at 400 ° C. for 3 hours to obtain α-Fe 2 O 3 . This was suspended in 5 liters of pure water, filtered, washed with pure water at 60 ° C., and dried.
こうして得られたα-Fe2O3を１０ｇ採取して回転炉へ装入し，Ｈ2気流を導入して４５０℃で１０時間加熱還元した。還元終了後，Ｎ2ガスを導入して室温まで冷却したうえ，１％のＯ2を含むＮ2ガスを導入して５時間の徐酸化処理を行なうことにより金属磁性粉を得た。 10 g of α-Fe 2 O 3 obtained in this manner was sampled and charged into a rotary furnace, and a H 2 gas stream was introduced and reduced by heating at 450 ° C. for 10 hours. After completion of the reduction, N 2 gas was introduced and cooled to room temperature, and N 2 gas containing 1% O 2 was introduced and subjected to a gradual oxidation treatment for 5 hours to obtain a metal magnetic powder.
この金属磁性粉の分析値並びに粉体特性と磁気特性を測定し，その結果を表１に示した。 The analytical values, powder properties and magnetic properties of this metal magnetic powder were measured, and the results are shown in Table 1.
なお表１において，ＢＥＴは比表面積，Ｘ線粒径はα-Fe の (110)面のＸ線回折ピークより算出した粒径（オングストローム），Ｈｃは保磁力（Ｏｅ），σs は飽和磁化（emu/g), σr/σsは角形比，Δσsは６０℃で９０ＲＨ（相対湿度）の雰囲気下で１週間放置したときのσs の低下率（％）を表す。 In Table 1, BET is the specific surface area, the X-ray particle size is the particle size (angstrom) calculated from the X-ray diffraction peak of the (110) plane of α-Fe, Hc is the coercive force (Oe), and σs is the saturation magnetization ( emu / g), σr / σs represents the squareness ratio, and Δσs represents the reduction rate (%) of σs when left at 60 ° C. in an atmosphere of 90 RH (relative humidity) for one week.
〔参考例２〕
純水５リットル中に硫酸アルミニウム［Ａｌ2（ＳＯ4）3］を４．８ｇ溶解させ、さらに１０％濃度のＮａＯＨ水溶液を使用してｐＨを１２．５に調整した。この溶液中に、Ｆｅに対して５％のＣoを含む長軸長さが０．２μｍで軸比１５のα−ＦｅＯＯＨを５０ｇ懸濁させて充分攪拌した後、このスラリー中に炭酸ガスを吹き込んでｐＨ９以下に中和することにより、該α−ＦｅＯＯＨ粒子の表面に含水・酸化アルミニウム（Ａｌ2Ｏ3・ｎＨ2Ｏ）を被覆させた。
[ Reference Example 2]
4.8 g of aluminum sulfate [Al 2 (SO 4 ) 3 ] was dissolved in 5 liters of pure water, and the pH was adjusted to 12.5 using a 10% strength aqueous NaOH solution. In this solution, 50 g of α-FeOOH containing 5% Co with respect to Fe and having a major axis length of 0.2 μm and an axial ratio of 15 was suspended and stirred sufficiently, and carbon dioxide gas was blown into the slurry. The surface of the α-FeOOH particles was coated with water-containing aluminum oxide (Al 2 O 3 .nH 2 O) by neutralizing to pH 9 or less.
この含水・酸化アルミニウム被着α-FeOOH粒子を濾過, 水洗, 乾燥後, ４００℃で３時間加熱して Al2O3被着α-Fe2O3に変成させた。次に, この Al2O3被着α-Fe2O3を解粒後,
純水に懸濁させ, 再度濾過し水洗することにより，Ｎa及び周期律第1a族元素が殆んど存在しないAl2O3 被着α-Fe2O3とした。
The water-containing / aluminum oxide-coated α-FeOOH particles were filtered, washed with water, dried, and then heated at 400 ° C. for 3 hours to be transformed into Al 2 O 3- coated α-Fe 2 O 3 . Next, after this Al 2 O 3 deposited α-Fe 2 O 3 was pulverized,
It was suspended in pure water, filtered again, and washed with water to obtain Al 2 O 3 -deposited α-Fe 2 O 3 with almost no Na and periodic group 1a elements.
こうして得られたＡｌを含有するα−Ｆｅ2Ｏ3を参考例１同様に加熱還元して金属磁性粉を得た。この金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。 The α-Fe 2 O 3 containing Al thus obtained was reduced by heating in the same manner as in Reference Example 1 to obtain a metal magnetic powder. Table 1 shows the analytical values, powder characteristics, and magnetic characteristics of this metal magnetic powder.
〔参考例３〕
参考例１と同様にして得たα−Ｆｅ2Ｏ3を、硝酸ランタン［Ｌａ（ＮＯ3）3］１．８ｇ溶かした１リットルの水溶液中へ懸濁させ、充分攪拌した後、このスラリーを乾燥機に入れて１００℃で水分を蒸発させ、Ｌａをα−Ｆｅ2Ｏ3に被着した。
[ Reference Example 3]
The α-Fe 2 O 3 obtained in the same manner as in Reference Example 1 was suspended in 1 liter of an aqueous solution in which 1.8 g of lanthanum nitrate [La (NO 3 ) 3 ] was dissolved. Water was evaporated at 100 ° C. in a dryer, and La was deposited on α-Fe 2 O 3 .
こうして得られたＬａを含有するα−Ｆｅ2Ｏ3を参考例１と同様に加熱還元して金属磁性粉を得た。この金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。 The thus obtained La-containing α-Fe 2 O 3 was heated and reduced in the same manner as in Reference Example 1 to obtain a metal magnetic powder. Table 1 shows the analytical values, powder characteristics, and magnetic characteristics of this metal magnetic powder.
〔実施例４〕
純水５リットル中に硫酸アルミニウム[Al2(SO4)3] 4.8 ｇを溶解させ，さらに10％濃度のNaOH水溶液を使用してpＨを12.5に調整した。この溶液中にＦeに対して５％のＣoを含む長軸長さ 0.2μｍ，軸比１５のα-FeOOHを５０ｇ懸濁させ, 充分に攪拌した後，このスラリー中に炭酸ガスを吹き込んでpＨ９以下に中和することにより，α-FeOOHの粒子表面に含水・酸化アルミニウム(Al2O3・nH2O) を被着させた。
Example 4
4.8 g of aluminum sulfate [Al 2 (SO 4 ) 3 ] was dissolved in 5 liters of pure water, and the pH was adjusted to 12.5 using a 10% NaOH aqueous solution. In this solution, 50 g of α-FeOOH having a major axis length of 0.2 μm containing 15% Co with respect to Fe and an axial ratio of 15 was suspended and stirred sufficiently. Carbon dioxide gas was blown into the slurry to obtain a pH of 9 Water neutralization and aluminum oxide (Al 2 O 3 · nH 2 O) were deposited on the α-FeOOH particle surface by neutralization as follows.
この含水・酸化アルミニウムを被着したα-FeOOHを濾過, 水洗, 乾燥後, ４００℃で３時間加熱して Al2O3被着α-Fe2O3に変成させた。次に, この Al2O3被着α-Fe2O3を解粒後, 純水に懸濁させ再度, 濾過・水洗し, Ｎa及び周期律第1a族元素のほとんどない Al2O3被着α-Fe2O3とした。 This water-containing / aluminum oxide-coated α-FeOOH was filtered, washed with water, dried, and then heated at 400 ° C. for 3 hours to be transformed into Al 2 O 3- coated α-Fe 2 O 3 . Next, this Al 2 O 3 coated α-Fe 2 O 3 is pulverized, suspended in pure water, filtered and washed again, and Al 2 O 3 coated with almost no Na and 1a group elements. Attached α-Fe 2 O 3 .
このものを，硝酸ランタン [Ｌa(NO3)3] 1.8ｇ溶かした１リットルの水溶液中へ懸濁させ, 充分攪拌した後，このスラリーを乾燥機に入れ, １００℃で水分を蒸発させてＬaを Al2O3被着α-Fe2O3に, さらに被着した。 This was suspended in 1 liter of an aqueous solution in which 1.8 g of lanthanum nitrate [La (NO 3 ) 3 ] was dissolved. After sufficient stirring, this slurry was placed in a dryer and the water was evaporated at 100 ° C. to form La. Was further deposited on Al 2 O 3 deposited α-Fe 2 O 3 .
こうして得られた Al2O3とＬaを含有するα-Fe2O3を１０ｇ採取して回転炉へ装入し,
Ｈ2気流を導入して４５０℃で１０時間加熱還元した。還元終了後Ｎ2ガスを導入して室温まで冷却した後，１％のＯ2を含むＮ2ガスを導入して５時間の徐酸化処理を行いＡlとＬaを含有する金属磁性粉を得た。この金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
10 g of α-Fe 2 O 3 containing Al 2 O 3 and La thus obtained was sampled and charged into a rotary furnace.
An H 2 gas stream was introduced and heating reduction was performed at 450 ° C. for 10 hours. After the reduction, N 2 gas was introduced and cooled to room temperature, then N 2 gas containing 1% O 2 was introduced, and a slow oxidation treatment was performed for 5 hours to obtain a metal magnetic powder containing Al and La. . Table 1 shows the analytical values, powder characteristics, and magnetic characteristics of this metal magnetic powder.
〔参考例５〕
参考例１で得られた金属磁性粉を、さらにＣＯ2を含む純水に懸濁させた後、濾過・水洗・乾燥した。なおこの一連の操作はＮ2雰囲気中で行った。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[ Reference Example 5]
The metal magnetic powder obtained in Reference Example 1 was further suspended in pure water containing CO 2 , filtered, washed with water, and dried. This series of operations was performed in an N 2 atmosphere. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔参考例６〕
参考例２で得られた金属磁性粉を、さらにＣＯ2を含む純水に懸濁させた後、濾過・水洗・乾燥した。この一連の操作はＮ2雰囲気中で行った。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[ Reference Example 6]
The metal magnetic powder obtained in Reference Example 2 was further suspended in pure water containing CO 2 , filtered, washed with water and dried. This series of operations was performed in an N 2 atmosphere. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔参考例７〕
純水中に溶解させた硫酸アルミニウム［Ａｌ2（ＳＯ4）3］を二倍とした以外は、すなわち参考例２で溶解させた４．８ｇを９．６ｇに変更した以外は、参考例６を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[ Reference Example 7]
Reference Example 6 except that aluminum sulfate [Al 2 (SO 4 ) 3 ] dissolved in pure water was doubled, ie, 4.8 g dissolved in Reference Example 2 was changed to 9.6 g. Was repeated. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔参考例８〕
参考例３で得られた金属磁性粉を、さらにＣＯ2を含む純水に懸濁させた後、濾過・水洗・乾燥した。この一連の操作はＮ2雰囲気中で行った。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[ Reference Example 8]
The metal magnetic powder obtained in Reference Example 3 was further suspended in pure water containing CO 2 , filtered, washed with water, and dried. This series of operations was performed in an N 2 atmosphere. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔参考例９〕
硝酸ランタンをほぼ二倍とした以外は（すなわち参考例３において硝酸ランタン［Ｌａ（ＮＯ3）3］を１リットル中１．８ｇ溶かした水溶液に代えて、硝酸ランタンを１リットル中３．７ｇ溶かした水溶液を用いた以外は）参考例８を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[ Reference Example 9]
Except for doubling the amount of lanthanum nitrate (ie, in Reference Example 3 instead of the aqueous solution in which 1.8 g of lanthanum nitrate [La (NO 3 ) 3 ] was dissolved in 1 liter, 3.7 g of lanthanum nitrate was dissolved in 1 liter). Reference Example 8 was repeated (except that an aqueous solution was used). Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１０〕
実施例４で得られた金属磁性粉を，さらにＣＯ2を含む純水に懸濁させた後，濾過・水洗・乾燥した。この一連の操作はＮ2雰囲気中で行った。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 10
The metal magnetic powder obtained in Example 4 was further suspended in pure water containing CO 2 , filtered, washed with water and dried. This series of operations was performed in an N 2 atmosphere. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１１〕
純水中に溶解させた硫酸アルミニウム[Al2(SO4)3] を 9.6ｇとし，且つ硝酸ランタン 3.7ｇを溶かした水溶液を使用した以外は，実施例４と同様にしてＡlとＬaを含有する金属磁性粉を得たうえ，さらにＣＯ2を含む純水に懸濁させた後，濾過・水洗・乾燥した。この一連の操作はＮ2雰囲気中で行った。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 11
Contains Al and La in the same manner as in Example 4 except that an aqueous solution containing 9.6 g of aluminum sulfate [Al 2 (SO 4 ) 3 ] dissolved in pure water and 3.7 g of lanthanum nitrate is used. The metal magnetic powder to be obtained was obtained, suspended in pure water containing CO 2 , filtered, washed and dried. This series of operations was performed in an N 2 atmosphere. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１２〕
硝酸ランタンに代えて硝酸テルビウム 3.9ｇを溶かした水溶液を使用した以外は，実施例１１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 12
Example 11 was repeated except that an aqueous solution in which 3.9 g of terbium nitrate was dissolved was used instead of lanthanum nitrate. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１３〕
硝酸ランタンに代えて硝酸セリウム 3.7ｇ溶かした水溶液を使用した以外は，実施例１１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 13
Example 11 was repeated except that an aqueous solution of 3.7 g of cerium nitrate was used instead of lanthanum nitrate. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１４〕
硝酸ランタンに代えて硝酸ネオジウム 3.7ｇを溶かした水溶液を使用した以外は，実施例１１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 14
Example 11 was repeated except that an aqueous solution in which 3.7 g of neodymium nitrate was dissolved was used instead of lanthanum nitrate. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１５〕
硝酸ランタンに代えて硝酸イットリウム 3.1ｇを溶かした水溶液を使用した以外は，実施例１１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 15
Example 11 was repeated except that an aqueous solution in which 3.1 g of yttrium nitrate was dissolved in place of lanthanum nitrate was used. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔実施例１６〕
長軸長が0.12μｍで軸比15のα-FeOOHを使用した以外は，実施例１５を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
Example 16
Example 15 was repeated except that α-FeOOH having a major axis length of 0.12 μm and an axial ratio of 15 was used. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔比較例１〕
４００℃にて３時間加熱して得たα−Ｆｅ2Ｏ3を、純水で洗浄する工程を省略して回転炉に直接装入した以外は、参考例１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[Comparative Example 1]
Reference Example 1 was repeated except that α-Fe 2 O 3 obtained by heating at 400 ° C. for 3 hours was directly charged into a rotary furnace without the step of washing with pure water. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔比較例２〕
長軸長が0.12μｍで軸比15のα-FeOOHを使用した以外は，比較例１を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[Comparative Example 2]
Comparative Example 1 was repeated except that α-FeOOH having a major axis length of 0.12 μm and an axial ratio of 15 was used. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔比較例３〕
４００℃で３時間加熱して得たAl2O3 被着α-Fe2O3を，純水で洗浄する工程を省略して回転炉に直接装入した以外は，実施例４を繰り返した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[Comparative Example 3]
Example 4 was repeated except that Al 2 O 3 -coated α-Fe 2 O 3 obtained by heating at 400 ° C. for 3 hours was directly charged into the rotary furnace without the step of washing with pure water. . Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
〔比較例４〕
長軸長が0.12μｍで軸比15のα-FeOOHを使用した以外は，実施例１５を繰り返したが，そのさいAl2O3 被着α-Fe2O3の純水で洗浄する工程と，磁性粉を最終的にＣＯ2を含む純水で洗浄する工程は省略した。得られた金属磁性粉の分析値並びに粉体特性と磁気特性を表１に示した。
[Comparative Example 4]
Example 15 was repeated except that α-FeOOH having a major axis length of 0.12 μm and an axial ratio of 15 was used. At that time, a step of washing with pure water of Al 2 O 3 coated α-Fe 2 O 3 and The step of finally cleaning the magnetic powder with pure water containing CO 2 was omitted. Table 1 shows analytical values, powder characteristics, and magnetic characteristics of the obtained metal magnetic powder.
以上の参考例１〜３、５〜９、実施例４、１０〜１６及び比較例１〜４で得られた各金属磁性粉を同一の条件で塗料化し、樹脂フイルム上に同一条件で塗布して磁気テープを作成したときのテープ特性を表２に示した。 The metal magnetic powders obtained in the above Reference Examples 1 to 3, 5 to 9, Examples 4, 10 to 16, and Comparative Examples 1 to 4 are coated under the same conditions and applied onto the resin film under the same conditions. Table 2 shows the tape characteristics when the magnetic tape was prepared.
表２において，粗度は表面粗さ計による測定値（オングストローム），光沢はグロスメーターによる光沢度，Ｂrは残留磁束密度 (ガウス), Ｂmは飽和磁束密度 (ガウス),
Ｂr/Ｂmは角形比, ＳＦＤは保磁力分布，ΔＢmは６０℃で９０ＲＨ（相対密度）の雰囲気下で１週間放置後のＢm の低下率（％），耐候試験後の析出物の有無は６０℃で９０ＲＨの雰囲気下で１週間放置後のテープ表面を顕微鏡観察したときの析出物の有無，そして出力の測定はＨi8デッキを用いて行った値である。
In Table 2, roughness is measured with a surface roughness meter (angstrom), gloss is gloss with gloss meter, Br is residual magnetic flux density (Gauss), Bm is saturation magnetic flux density (Gauss),
Br / Bm is the squareness ratio, SFD is the coercive force distribution, ΔBm is the decrease rate (%) of Bm after standing for 1 week in an atmosphere of 90 RH (relative density) at 60 ° C., and the presence or absence of precipitates after the weathering test is 60 The presence or absence of precipitates and the measurement of output when the surface of the tape was allowed to stand for 1 week at 90 ° C. in an atmosphere at 90 ° C. were measured using a Hi8 deck.
表１および表２の結果から次のことがわかる。 The following can be understood from the results of Tables 1 and 2.
(1) 比較例のように，Ｎa,Ｃaの除去処理を施さなかったものは，分散しにくく (比較例１），分散されてもテープの耐候性が低い (比較例１）ものであり，６０℃，９０ＲＨで１週間置いたテープの表面には結晶が析出し保存安定性の悪い（比較例１〜４）のに対し，Ｎa,Ｃaの除去処理を施した実施例品は分散性が良好で，テープの耐久性および保存安定性に優れる。 (1) As in the comparative example, the Na and Ca removal treatments were not dispersed (Comparative Example 1), and even when dispersed, the tape had low weather resistance (Comparative Example 1). Crystals are deposited on the surface of the tape placed at 60 ° C. and 90 RH for one week, and the storage stability is poor (Comparative Examples 1 to 4). Good, excellent tape durability and storage stability.
（２）Ｎａ、Ｃａの除去処理を施したうえ、Ａｌを添加したものは、例えば参考例１と２との比較、或いは参考例５と６または７との比較から明らかなように、磁性粉の磁気特性が向上し（Ｈｃ、σｒ／σｓが向上し、Δσｓが低下する)、テープ特性についても磁気特性が向上すると共に角形比、ＳＦＤ、ΔＢｍ等も改善される。 (2) Na, Ca removal treatment and addition of Al are, for example, as shown in the comparison between Reference Examples 1 and 2, or the comparison between Reference Examples 5 and 6 or 7, and magnetic powder (Hc, σr / σs is improved and Δσs is reduced), the magnetic properties of the tape are improved, and the squareness ratio, SFD, ΔBm and the like are also improved.
（３）Ｎａ、Ｃａの除去処理を施したうえ、希土類元素を添加したものは、例えば参考例１と３の比較、或いは参考例５と８または９との比較から明らかなように、磁性粉の磁気特性が向上し（Ｈｃ、σｒ／σｓが向上し、Δσｓが低下する）、テープ特性についても磁気特性が向上すると共に角形比、ＳＦＤ、ΔＢｍ等も改善される。 (3) As for the thing which added the rare earth element after performing the removal process of Na and Ca, for example, it becomes clear from the comparison with the reference examples 1 and 3, or the comparison with the reference examples 5, 8 or 9, and magnetic powder. (Hc, [sigma] r / [sigma] s is improved and [Delta] [sigma] s is reduced), the magnetic properties of the tape are improved, and the squareness ratio, SFD, [Delta] Bm and the like are also improved.
(4) Ｎa,Ｃaの除去処理を施したうえ，Ａlおよび希土類元素を添加したものは磁性粉の磁気特性がさらに向上し（Ｈｃ，σr/σsが向上し，Δσsが低下する),テープ特性についても磁気特性がさらに向上すると共に角形比，ＳＦＤ，ΔＢm 等も一層改善され，飛躍的に磁気特性及びテープ特性が向上する。また分散性，保存安定性に優れるので理想的な金属磁性粉となる。 (4) When Na and Ca are removed and Al and rare earth elements are added, the magnetic properties of the magnetic powder are further improved (Hc, σr / σs is improved and Δσs is reduced), and tape properties In addition, the magnetic characteristics are further improved and the squareness ratio, SFD, ΔBm, etc. are further improved, and the magnetic characteristics and the tape characteristics are dramatically improved. In addition, it has excellent dispersibility and storage stability, making it an ideal metal magnetic powder.
(5) また，かような改善効果は，例えば実施例１５と１６の比較から明らかなように微粒子ほど顕著である。 (5) Further, such an improvement effect is more remarkable for fine particles as is apparent from the comparison between Examples 15 and 16, for example.
以上説明したように，本発明によれば, 周期律表第１ａ元素が含まれないので樹脂との相溶性がよく且つ分散性およびテープ耐久性の良い金属磁性粉末が得られ, 保存安定性に優れた高密度磁気記録媒体を提供できる。 As described above, according to the present invention, since the element 1a of the periodic table is not included, a metal magnetic powder having good compatibility with the resin, good dispersibility and tape durability can be obtained, and storage stability can be improved. An excellent high-density magnetic recording medium can be provided.
更に，希土類元素及びＡlの相互作用により優れた焼結防止効果を発揮するため針状性，分散性に優れた磁気異方性の高い金属磁性粉が得られる。 Furthermore, since an excellent sintering preventing effect is exhibited by the interaction between the rare earth element and Al, a metal magnetic powder having excellent acicularity and dispersibility and high magnetic anisotropy can be obtained.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005124882A JP4336786B2 (en) | 2005-04-22 | 2005-04-22 | Method for producing ferromagnetic metal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005124882A JP4336786B2 (en) | 2005-04-22 | 2005-04-22 | Method for producing ferromagnetic metal powder |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5186578A Division JPH0722224A (en) | 1993-07-01 | 1993-07-01 | Ferromagnetic metal powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2005281868A JP2005281868A (en) | 2005-10-13 |
| JP4336786B2 true JP4336786B2 (en) | 2009-09-30 |
Family
ID=35180574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005124882A Expired - Lifetime JP4336786B2 (en) | 2005-04-22 | 2005-04-22 | Method for producing ferromagnetic metal powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4336786B2 (en) |
-
2005
- 2005-04-22 JP JP2005124882A patent/JP4336786B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2005281868A (en) | 2005-10-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5645652A (en) | Spindle-shaped magnetic iron-based alloy particles containing cobalt and iron as the main ingredients and process for producing the same | |
| JPH0722224A (en) | Ferromagnetic metal powder | |
| US5591535A (en) | Ferromagnetic metal powder | |
| JP5130456B2 (en) | Ferromagnetic metal powder and magnetic recording medium using the same | |
| JP2004319923A (en) | Iron nitride-based magnetic powder | |
| JP4670088B2 (en) | Ferromagnetic metal powder for magnetic recording medium and magnetic recording medium using the same | |
| JP4143713B2 (en) | Magnetic powder for magnetic recording | |
| JP4336786B2 (en) | Method for producing ferromagnetic metal powder | |
| JP3337046B2 (en) | Spindle-shaped metal magnetic particles containing cobalt and iron as main components and method for producing the same | |
| JP2003247002A (en) | Metal magnetic grain powder essentially consisting of iron, production method thereof and magnetic recording medium | |
| JP2005336606A (en) | Powder of ferromagnetic metal | |
| JP2005264334A (en) | Ferromagnetic metal powder | |
| JP2010092587A (en) | Ferromagnetic metal powder and magnetic recording medium using the same | |
| JP4378763B2 (en) | Method for producing compound particle powder containing iron as its main component | |
| US5989516A (en) | Spindle-shaped geothite particles | |
| JPH11251122A (en) | Precursor for manufacturing magnetic powder and ferromagnetic metal power obtained from the same | |
| JP2003045709A (en) | Ferromagnetic metal powder and manufacturing method therefor | |
| JPH0647681B2 (en) | Spindle-shaped iron-based metallic magnetic particle powder and method for producing the same | |
| JP2008084418A (en) | Magnetic recording medium and method for manufacturing the same | |
| JP2006041210A (en) | Iron-nitride magnetic powder excellent in weatherability | |
| JP2678480B2 (en) | Metal magnetic powder | |
| JP2933397B2 (en) | Method for producing ferromagnetic iron oxide powder for magnetic recording | |
| JP2945458B2 (en) | Acicular ferromagnetic iron oxide powder and method for producing the same | |
| JPH08165117A (en) | Spindlelike geothite particulate powder containing cobalt and its production | |
| JP4669916B2 (en) | Method for producing magnetic powder for magnetic recording |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050512 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20080115 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20080317 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20080930 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20090422 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20090605 |
|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20090605 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090605 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20090605 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120710 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120710 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130710 Year of fee payment: 4 |
|
| EXPY | Cancellation because of completion of term |