JPH0416924B2 - - Google Patents
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- Publication number
- JPH0416924B2 JPH0416924B2 JP59027849A JP2784984A JPH0416924B2 JP H0416924 B2 JPH0416924 B2 JP H0416924B2 JP 59027849 A JP59027849 A JP 59027849A JP 2784984 A JP2784984 A JP 2784984A JP H0416924 B2 JPH0416924 B2 JP H0416924B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- feooh
- magnetic powder
- terms
- spindle
- Prior art date
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- 229910001566 austenite Inorganic materials 0.000 claims description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 14
- 239000006247 magnetic powder Substances 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 229910006540 α-FeOOH Inorganic materials 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 230000004907 flux Effects 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 7
- 239000000243 solution Substances 0.000 claims description 7
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 5
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 229910006299 γ-FeOOH Inorganic materials 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 238000007664 blowing Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 239000002344 surface layer Substances 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims 1
- 239000010941 cobalt Substances 0.000 claims 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims 1
- 150000002506 iron compounds Chemical class 0.000 claims 1
- 229910000029 sodium carbonate Inorganic materials 0.000 claims 1
- 239000002245 particle Substances 0.000 description 11
- 229960002089 ferrous chloride Drugs 0.000 description 6
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 4
- 230000000877 morphologic effect Effects 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 229910052911 sodium silicate Inorganic materials 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 241000289669 Erinaceus europaeus Species 0.000 description 1
- 229910002588 FeOOH Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- -1 ferrous compound Chemical class 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
Description
【発明の詳細な説明】
本発明は、磁気記録媒体用としてすぐれた特性
を有する改善されたγ−Fe2O3磁性粉及びその製
造方法に関する。さらに詳しくは、本発明は高密
度記録媒体用として特に適した改善されたγ−
Fe2O3粉末及びその製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved γ-Fe 2 O 3 magnetic powder having excellent properties for use in magnetic recording media and a method for producing the same. More specifically, the present invention provides improved γ-
This invention relates to Fe 2 O 3 powder and its manufacturing method.
現在使用されている磁気記録媒体は極めて多様
であり、そのような多様な磁気記録媒体の製造に
用いられる磁性粉に要求される諸特性は個々の記
録媒体に応じてそれぞれ異なつている。γ−
Fe2O3は従来より用いられている代表的な磁性粉
の一つである。しかし近年高密度磁気記録の要求
が高まり、また保持力、飽和磁束密度等の磁気特
性の向上も望まれている。このような要求や要望
に沿うものとして金属磁性粉（メタル粉あるいは
メタリツク粉とも称される）が注目されてきてい
るが、このような金属磁性粉の保持力（Hc）は、
通常1100〜1300エルステツド（Oe）の範囲にあ
り、その保磁力の高さ故にメタル記録媒体に対応
させたもの以外のオーデイオ機器、ビデオ機器及
びデジタル記録・再生機器等のための磁気記録媒
体の製造に都合良く使用できないという欠点を有
している。 The magnetic recording media currently in use are extremely diverse, and the characteristics required of the magnetic powder used to manufacture such various magnetic recording media differ depending on the individual recording media. γ-
Fe 2 O 3 is one of the typical magnetic powders conventionally used. However, in recent years, demands for high-density magnetic recording have increased, and improvements in magnetic properties such as coercive force and saturation magnetic flux density are also desired. Metal magnetic powder (also referred to as metal powder or metallic powder) has been attracting attention as a material that meets these requirements and demands, but the coercive force (Hc) of such metal magnetic powder is
Manufacture of magnetic recording media for audio equipment, video equipment, digital recording/playback equipment, etc. other than those compatible with metal recording media, which are usually in the range of 1100 to 1300 oersteds (Oe) and are compatible with metal recording media due to their high coercive force. It has the disadvantage that it cannot be used conveniently.
またγ−Fe2O3磁性粉についても、それにCoを
ドープして保磁力を向上させるような工夫がなさ
れているが、従来得られるγ−Fe2O3の粒子自体
が1μを越えるような長軸長を有するので、Coド
ープ処理をしても高密度記録用途における要求を
満足させることができない。そこでγ−Fe2O3を
得るのに一般的に用いられる原料である針状含水
酸化鉄を製造する際にその粒径を1μ以下、例え
ば0.5〜0.7μ程度に抑えることが提案されている
が、そのようにしても途中でFe3O4に還元すると
きに粒子間の焼結が起り、製品の保磁力が低くな
り、また分散性も悪化する欠点がある。 Efforts have also been made to improve the coercive force of γ-Fe 2 O 3 magnetic powder by doping it with Co, but the conventionally obtained γ-Fe 2 O 3 particles themselves are larger than 1μ Since it has a long axis length, even if it is Co-doped, it cannot satisfy the requirements for high-density recording applications. Therefore, it has been proposed that when manufacturing acicular hydrated iron oxide, which is a raw material commonly used to obtain γ-Fe 2 O 3 , the particle size should be kept below 1μ, for example, around 0.5 to 0.7μ. However, even if this is done, sintering between particles occurs during reduction to Fe 3 O 4 during the process, resulting in lower coercive force and poor dispersibility of the product.
本発明は、上記の諸欠点を解消し、VTR用テ
ープ等の高密度記録用の磁気記録媒体の製造に適
する改善されたγ−Fe2O3磁性粉を提供する。本
発明によるγ−Fe2O3は、平均長軸長が0.1〜0.5μ
であつて従来のものに比して非常に微小であり、
針状比（長軸長：短軸長の比）が1.5〜５であり、
その形状が紡錘形またはそれに近いものであると
いう形態的特徴；Co分が金属Co換算で１〜10重
量％、好ましくは３〜５重量％表面層にあり、
SiO2が0.05〜0.5重量％（いずれもγ−Fe2O3基
準）ドープされているという成分的な特徴；なら
びに保磁力が550〜700Oe、飽和磁束密度が
70emu／ｇ以上であり従来のγ−Fe2O3のものよ
りも大幅に向上しているという磁気特性上の特
徴；を示すものであり、これらを考慮すれば新規
なγ−Fe2O3磁性粉であると考えられる。 The present invention eliminates the above-mentioned drawbacks and provides an improved γ-Fe 2 O 3 magnetic powder suitable for manufacturing magnetic recording media for high-density recording such as VTR tapes. The γ-Fe 2 O 3 according to the present invention has an average long axis length of 0.1 to 0.5μ
It is very small compared to conventional ones,
The acicular ratio (ratio of major axis length: short axis length) is 1.5 to 5,
The morphological feature is that the shape is spindle-shaped or something close to it; the Co content is 1 to 10% by weight, preferably 3 to 5% by weight in terms of metal Co, in the surface layer,
It has a component characteristic of being doped with 0.05 to 0.5% by weight of SiO 2 (all based on γ-Fe 2 O 3 ); it also has a coercive force of 550 to 700 Oe and a saturation magnetic flux density.
70 emu/g or more, which is significantly improved over that of conventional γ- Fe 2 O 3 . It is thought to be magnetic powder.
本発明によれば、上記の改善されたγ−Fe2O3
磁性粉を製造する方法も提供される。本発明のγ
−Fe2O3磁性粉は下記のようにして製造できる。 According to the present invention, the above-mentioned improved γ-Fe 2 O 3
A method of making magnetic powder is also provided. γ of the present invention
−Fe 2 O 3 magnetic powder can be produced as follows.
まず、塩化第一鉄、硫酸第一鉄等の水溶性第一
鉄塩を0.1〜0.5mol／の濃度で含む水溶液を準
備し、この水溶液に第一鉄塩に対して規定量にし
て1.5〜５倍量、好ましくは２〜2.5倍量の炭酸ソ
ーダを添加し、さらに、水溶性のSi源化合物を生
成α−FeOOHにSiO2として0.05〜0.5重量％含ま
れる量添加した後、例えば20〜60℃で、空気（あ
るいはその他の酸素含有気体）を吹き込み酸化す
ることによつてα−FeOOHを生成させる。この
場合に炭酸ソーダの量を上記範囲よりも少なくす
ると、生成α−FeOOHがいがぐり型（ハリネズ
ミ型）を呈する傾向が増し、好ましくない。また
使用する水溶性Si源化合物の例としては、シリカ
ゾル、コロイダルシリカ、水ガラス等を挙げるこ
とができる。 First, prepare an aqueous solution containing a water-soluble ferrous salt such as ferrous chloride or ferrous sulfate at a concentration of 0.1 to 0.5 mol, and add a specified amount of ferrous salt to this aqueous solution to 1.5 to After adding 5 times the amount, preferably 2 to 2.5 times the amount of soda carbonate, and further adding a water-soluble Si source compound in an amount containing 0.05 to 0.5% by weight as SiO 2 to the generated α-FeOOH, for example, 20 to α-FeOOH is produced by oxidation by blowing air (or other oxygen-containing gas) at 60°C. In this case, if the amount of soda carbonate is less than the above range, the produced α-FeOOH tends to exhibit a hedgehog shape, which is not preferable. Examples of the water-soluble Si source compound used include silica sol, colloidal silica, and water glass.
以上の操作によつて得られるα−FeOOHは、
平均長軸長が約0.1〜0.5μと小さく、また針状比
が約1.5〜５の範囲にあり、紡錘形もしくはそれ
に近い形状である。上記で使用するSi源化合物
は、生成するα−FeOOHの粒径をコントロール
する効果を示すと同時に以後のγ−Fe2O3生成処
理における粒子の焼結を防止する効果をも示す。 α-FeOOH obtained by the above operations is
The average major axis length is as small as about 0.1 to 0.5 μ, and the acicular ratio is in the range of about 1.5 to 5, and the shape is spindle-shaped or close to it. The Si source compound used above exhibits the effect of controlling the particle size of the generated α-FeOOH, and at the same time exhibits the effect of preventing particle sintering in the subsequent γ-Fe 2 O 3 generation process.
該紡錘状α−FeOOHは通常の方法により
過、乾燥、脱水、還元再酸化することによりγ−
Fe2O3とする（以上、第１段階）。このγ−Fe2O3
においては、上記紡錘状α−FeOOHの形態的特
徴が良く維持されている。 The spindle-shaped α-FeOOH is converted into γ-FeOOH by filtration, drying, dehydration, reduction and reoxidation using conventional methods.
Fe 2 O 3 (the above is the first step). This γ−Fe 2 O 3
In this case, the morphological characteristics of the spindle-shaped α-FeOOH are well maintained.
このようにして得られたγ−Fe2O3を、水溶性
Co化合物（および場合により水溶性第一鉄化合
物）を含む水溶液に分散させ、アルカリで中和す
ることによりCo分（および使用する場合にはFe
分）をγ−Fe2O3に対して１〜10重量％、好まし
くは３〜５重量％（金属Co換算）被着させ、こ
れを過、洗浄、乾燥する。かくして得られる
Co含有γ−Fe2O3においても、最初のα−
FeOOHの形態が実質的に受け継がれている。こ
のγ−Fe2O3は前記の如き好ましい磁気特性を示
す。 The γ-Fe 2 O 3 obtained in this way is made into a water-soluble
The Co content (and Fe, if used) is removed by dispersing it in an aqueous solution containing the Co compound (and possibly a water-soluble ferrous compound) and neutralizing it with an alkali.
1 to 10% by weight, preferably 3 to 5% by weight (in terms of metal Co) of γ-Fe 2 O 3 , and this is filtered, washed, and dried. thus obtained
Even in Co-containing γ-Fe 2 O 3 , the initial α-
The form of FeOOH is essentially inherited. This γ-Fe 2 O 3 exhibits favorable magnetic properties as described above.
以下実施例に本発明をさらに説明する。 The present invention will be further explained in the following examples.
実施例 １
炭酸ソーダ20Kgを水180に溶解して反応器に
投入し、次いでケイ酸ソーダをSiO2換算で35ｇ
の量で水２に溶解した溶液を添加し、さらに塩
化第一鉄90モルを水65に溶解した溶液を投入し
た後50℃まで昇温した。次いで空気を60／分の
流量で吹き込み、反応温度を50℃に保ちつつ６時
間酸化反応を行わせα−FeOOHを生成させた。Example 1 20 kg of soda carbonate was dissolved in 180 kg of water and charged into a reactor, and then 35 g of sodium silicate was added in terms of SiO 2
A solution prepared by dissolving 90 mol of ferrous chloride in 65 mol of water was added thereto, and the temperature was raised to 50°C. Next, air was blown in at a flow rate of 60/min to carry out an oxidation reaction for 6 hours while maintaining the reaction temperature at 50°C to generate α-FeOOH.
このようにして得たα−FeOOHを過、洗
浄、乾燥し、次いで電気炉に入れ、常法により脱
水、還元、再酸化処理してγ−Fe2O3とした。 The α-FeOOH thus obtained was filtered, washed, and dried, then placed in an electric furnace, and subjected to dehydration, reduction, and reoxidation treatment by conventional methods to obtain γ-Fe 2 O 3 .
このγ−Fe2O310Kgを水130中に良く撹拌分
散させ、別に塩化コバルトをγ−Fe2O3に対して
金属Co換算で５重量％及ひ塩化第一鉄を同様に
金属Fe換算で10重量％水30に溶解した溶液を
添加した。次にNaOHを200モルを水30に溶解
した溶液を添加した。窒素ガスを60／分の流量
で吹き込み、80℃まで加熱して２時間保持し、γ
−Fe2O3粒子の表面にCo分を被着させた。これ
を、過、洗浄、乾燥して得たCo被着γ−Fe2O3
は平均長軸長が0.2μ、平均短軸長が0.05μで、紡
錘型であつた。このものの保磁力は650Oe、飽和
磁束密度は73emu／ｇであつた。 10 kg of this γ-Fe 2 O 3 was well stirred and dispersed in 130 ml of water, and separately, 5% by weight of cobalt chloride was added to γ-Fe 2 O 3 in terms of metal Co, and ferrous chloride was similarly added in terms of metal Fe. A solution of 10% by weight dissolved in water at 30% was added. A solution of 200 moles of NaOH dissolved in 30 parts of water was then added. Blow nitrogen gas at a flow rate of 60/min, heat to 80℃, hold for 2 hours, and
- Co was deposited on the surface of Fe 2 O 3 particles. Co-coated γ-Fe 2 O 3 obtained by filtering, washing and drying this
The average major axis length was 0.2μ, the average short axis length was 0.05μ, and it was spindle-shaped. This material had a coercive force of 650 Oe and a saturation magnetic flux density of 73 emu/g.
実施例 ２
実施例１の操作と同様にしてCo被着γ−Fe2O3
を得たが、本実施例ではα−FeOOHの製造の際
にケイ酸ソーダをSiO2換算で７ｇ使用し、また
γ−Fe2O3にCo分を被着させる際に塩化コバルト
をγ−Fe2O3に対して金属Co換算で３重量％そし
て塩化第一鉄を同様に金属Fe換算で７重量％使
用した。Example 2 Co-deposited γ-Fe 2 O 3 in the same manner as in Example 1
However, in this example, when producing α-FeOOH, 7 g of sodium silicate was used in terms of SiO 2 , and when depositing Co on γ-Fe 2 O 3 , cobalt chloride was used as γ-FeOOH. Fe 2 O 3 was used in an amount of 3% by weight in terms of Co metal, and ferrous chloride was similarly used in an amount of 7% by weight in terms of Fe metal.
かくして得られたCo被着γ−Fe2O3粒子は平均
長軸長0.35μ、平均短軸長0.08μで、紡錘型であつ
た。このものの保磁力は620Oe、飽和磁束密度
73emu／ｇであつた。 The thus obtained Co-coated γ-Fe 2 O 3 particles had an average major axis length of 0.35μ, an average minor axis length of 0.08μ, and were spindle-shaped. The coercive force of this item is 620Oe, the saturation magnetic flux density
It was 73 emu/g.
比較例 １
実施例１の操作によつてケイ酸ソーダを添加し
ないでCo被着γ−Fe2O3を製造した。得られた結
晶粒子は平均長軸長0.6μ、平均短軸長0.1μで、紡
錘状の外観を呈したが、磁気記録媒体とした場合
にノイズが大きい欠点を有した。これは殊にビデ
オ用途において望ましくない特性である。Comparative Example 1 Co-coated γ-Fe 2 O 3 was produced by the procedure of Example 1 without adding sodium silicate. The obtained crystal grains had an average long axis length of 0.6 μm and an average short axis length of 0.1 μm, and had a spindle-like appearance, but had the drawback of large noise when used as a magnetic recording medium. This is an undesirable property, especially in video applications.
比較例 ２
実施例１の操作において炭酸ソーダの使用量を
13Kgとし、中和率をFeの1.3倍として、実施例１
の操作を繰返した。得られたγ−Fe2O3粒子には
いがぐり型の凝集粒子が可成りの割合で混在して
いた。この製品粉末は磁性塗料調製の際にビヒク
ルへの分散性が悪いという重大な欠点を示した。Comparative Example 2 In the operation of Example 1, the amount of soda carbonate used was
Example 1 with a weight of 13Kg and a neutralization rate of 1.3 times that of Fe.
The operation was repeated. The obtained γ-Fe 2 O 3 particles contained a considerable proportion of burr-shaped agglomerated particles. This product powder exhibited a serious drawback of poor dispersibility in vehicles during the preparation of magnetic coatings.
比較例 ３
実施例１の操作においてCo被着処理を施さな
いγ−Fe2O3の保磁力は300Oe、飽和磁束密度は
70emu／ｇであつた。Comparative Example 3 The coercive force of γ-Fe 2 O 3 without Co deposition treatment in the operation of Example 1 was 300 Oe, and the saturation magnetic flux density was
It was 70emu/g.
実施例 ３
実施例１の操作を繰返したがCo被着用溶液中
に塩化第一鉄を存在させないで実施した。Example 3 The procedure of Example 1 was repeated but without the presence of ferrous chloride in the Co deposition solution.
得られた最終のγ−Fe2O3粒子は実施例１のも
のと実質的に同じ形態的特徴を示した。保磁力は
625Oe、飽和磁束密度は72emu／ｇであつた。 The final γ-Fe 2 O 3 particles obtained exhibited substantially the same morphological characteristics as those of Example 1. The coercive force is
625 Oe, and the saturation magnetic flux density was 72 emu/g.
実施例 ４
実施例２の操作を繰返したがCo被着用溶液中
に塩化第一鉄を存在させずに実施した。Example 4 The procedure of Example 2 was repeated but without the presence of ferrous chloride in the Co deposition solution.
得られたCo被着γ−Fe2O3粒子は実施例２のも
のと実質的に同じ形態的特徴を示した。保磁力は
600Oe、飽和磁束密度は71emu／ｇであつた。 The resulting Co-coated γ-Fe 2 O 3 particles exhibited substantially the same morphological characteristics as those of Example 2. The coercive force is
600 Oe, and the saturation magnetic flux density was 71 emu/g.
Claims (1)
あり、かつCo分が金属Co換算で１〜10重量％表
面層にあり、SiO2が0.05〜0.5重量％ドープされ
ている、高密度記録媒体製造用に適した紡錘状γ
−Fe2O3磁性粉。 ２ 保磁力が550〜700エルステツドである特許請
求の範囲第１項に記載の磁性粉。 ３ 飽和磁束密度が70emu／ｇ以上である特許請
求の範囲第１または２項に記載の磁性粉。 ４ (イ) 第一鉄塩水溶液に、第一鉄塩に対して規
定量にして1.5〜５倍量の炭酸ソーダ及び生成
α−FeOOHに対してSiO2として0.05〜0.5重量
％含まれる量のSi源化合物を添加し、酸素含有
気体を吹き込みα−FeOOHを生成させ、これ
を脱水、還元、再酸化することによりγ−
Fe2O3を得る第１段階と、 (ロ) かくして得られたγ−Fe2O3をCo化合物水溶
液に分散させてCo分をいずれかの形で被着さ
せる処理をした後、過、洗浄乾燥する第２段
階と、 からなることを特徴とする紡錘状γ−Fe2O3磁性
粉の製造方法。 ５ 第２段階におけるCo分被着量は金属コバル
ト換算で１〜10重量％である特許請求の範囲第４
項に記載の方法。 ６ 第２段階らおけるCo化合物水溶液中に水溶
性鉄化合物をも存在させてFe分をいずれかの形
でγ−Fe2O3に被着させる特許請求の範囲第４ま
たは５項に記載の方法。[Claims] 1. The average major axis length is 0.1 to 0.5μ, the acicular ratio is 1.5 to 5, and the Co content is 1 to 10% by weight in terms of metal Co in the surface layer, and the SiO 2 content is 0.05 to 0.5. Spindle-shaped γ doped with 0.5% by weight, suitable for manufacturing high-density recording media
−Fe 2 O 3 magnetic powder. 2. The magnetic powder according to claim 1, which has a coercive force of 550 to 700 oersteds. 3. The magnetic powder according to claim 1 or 2, which has a saturation magnetic flux density of 70 emu/g or more. 4 (a) In the ferrous salt aqueous solution, add 1.5 to 5 times the specified amount of sodium carbonate to the ferrous salt and 0.05 to 0.5% by weight of SiO 2 based on the generated α-FeOOH. By adding a Si source compound and blowing in oxygen-containing gas to generate α-FeOOH, this is dehydrated, reduced, and reoxidized to produce γ-FeOOH.
( b) After dispersing the thus obtained γ-Fe 2 O 3 in an aqueous Co compound solution and depositing Co in any form, filtration, A method for producing spindle-shaped γ-Fe 2 O 3 magnetic powder, comprising a second step of washing and drying. 5. The amount of Co deposited in the second stage is 1 to 10% by weight in terms of metallic cobalt.
The method described in section. 6. The method according to claim 4 or 5, in which a water-soluble iron compound is also present in the aqueous Co compound solution in the second step, and the Fe component is deposited in any form on the γ-Fe 2 O 3 . Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59027849A JPS60170906A (en) | 1984-02-16 | 1984-02-16 | Spindle shaped gamma-fe2o3 magnetic powder including co and manufacture of the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59027849A JPS60170906A (en) | 1984-02-16 | 1984-02-16 | Spindle shaped gamma-fe2o3 magnetic powder including co and manufacture of the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60170906A JPS60170906A (en) | 1985-09-04 |
| JPH0416924B2 true JPH0416924B2 (en) | 1992-03-25 |
Family
ID=12232361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59027849A Granted JPS60170906A (en) | 1984-02-16 | 1984-02-16 | Spindle shaped gamma-fe2o3 magnetic powder including co and manufacture of the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60170906A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6117425A (en) * | 1984-06-30 | 1986-01-25 | Toda Kogyo Corp | Magnetic iron oxide particle powder showing spindle shape and its preparation |
| KR960705740A (en) * | 1993-11-01 | 1996-11-08 | 워렌 리차드 보비 | PROCESS FOR MAKING GOETHITE |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5626729A (en) * | 1979-08-11 | 1981-03-14 | Tdk Corp | Powdered magnetic material for magnetic recording medium |
-
1984
- 1984-02-16 JP JP59027849A patent/JPS60170906A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5626729A (en) * | 1979-08-11 | 1981-03-14 | Tdk Corp | Powdered magnetic material for magnetic recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60170906A (en) | 1985-09-04 |
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