JP3253768B2 - Method for producing cobalt-containing magnetic iron oxide having hemimorphite coating - Google Patents
Method for producing cobalt-containing magnetic iron oxide having hemimorphite coatingInfo
- Publication number
- JP3253768B2 JP3253768B2 JP18389593A JP18389593A JP3253768B2 JP 3253768 B2 JP3253768 B2 JP 3253768B2 JP 18389593 A JP18389593 A JP 18389593A JP 18389593 A JP18389593 A JP 18389593A JP 3253768 B2 JP3253768 B2 JP 3253768B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- compound
- coating
- hemimorphite
- iron oxide
- 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 - Fee Related
Links
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims description 33
- 230000005291 magnetic effect Effects 0.000 title claims description 24
- 229910052864 hemimorphite Inorganic materials 0.000 title claims description 18
- 229910017052 cobalt Inorganic materials 0.000 title claims description 11
- 239000010941 cobalt Substances 0.000 title claims description 11
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 title claims description 11
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 238000000576 coating method Methods 0.000 title description 20
- 239000011248 coating agent Substances 0.000 title description 19
- 229910052725 zinc Inorganic materials 0.000 claims description 40
- 229910052710 silicon Inorganic materials 0.000 claims description 35
- 150000001875 compounds Chemical class 0.000 claims description 33
- 239000006247 magnetic powder Substances 0.000 claims description 24
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 21
- 229910052782 aluminium Inorganic materials 0.000 claims description 18
- 238000010335 hydrothermal treatment Methods 0.000 claims description 17
- 239000000843 powder Substances 0.000 claims description 13
- 239000002002 slurry Substances 0.000 claims description 11
- 239000013078 crystal Substances 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 239000011701 zinc Substances 0.000 description 60
- 239000010410 layer Substances 0.000 description 15
- 238000000034 method Methods 0.000 description 13
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 230000003078 antioxidant effect Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 235000014113 dietary fatty acids Nutrition 0.000 description 9
- 239000000194 fatty acid Substances 0.000 description 9
- 229930195729 fatty acid Natural products 0.000 description 9
- 150000004665 fatty acids Chemical class 0.000 description 9
- 230000005415 magnetization Effects 0.000 description 9
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000000151 deposition Methods 0.000 description 7
- 238000001179 sorption measurement Methods 0.000 description 7
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 7
- 229910000368 zinc sulfate Inorganic materials 0.000 description 7
- 229960001763 zinc sulfate Drugs 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 5
- 101000993059 Homo sapiens Hereditary hemochromatosis protein Proteins 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 230000032683 aging Effects 0.000 description 4
- 230000003064 anti-oxidating effect Effects 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000003973 paint Substances 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 235000011121 sodium hydroxide Nutrition 0.000 description 4
- 229910052911 sodium silicate Inorganic materials 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 235000019795 sodium metasilicate Nutrition 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000005294 ferromagnetic effect Effects 0.000 description 2
- 229910052598 goethite Inorganic materials 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 150000003377 silicon compounds Chemical class 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- VSGNNIFQASZAOI-UHFFFAOYSA-L calcium acetate Chemical compound [Ca+2].CC([O-])=O.CC([O-])=O VSGNNIFQASZAOI-UHFFFAOYSA-L 0.000 description 1
- 239000001639 calcium acetate Substances 0.000 description 1
- 235000011092 calcium acetate Nutrition 0.000 description 1
- 229960005147 calcium acetate Drugs 0.000 description 1
- OSMSIOKMMFKNIL-UHFFFAOYSA-N calcium;silicon Chemical compound [Ca]=[Si] OSMSIOKMMFKNIL-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000009614 chemical analysis method Methods 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 150000001869 cobalt compounds Chemical class 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- -1 iron oxide compound Chemical class 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/10—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
- H01F1/11—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
- H01F1/112—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles with a skin
Landscapes
- Health & Medical Sciences (AREA)
- Dermatology (AREA)
- General Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Compounds Of Iron (AREA)
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、塗布型高密度磁気記録
媒体に用いられる磁性粉末において、Ｆｅ2+含有量の多
いベルトライド化合物を核晶としたコバルト含有磁性酸
化鉄の欠点であるＦｅ2+含有量、保磁力及び飽和磁化量
などの経時安定性を改良した、ヘミモルファイト被膜を
有するコバルト含有磁性酸化鉄粉末の製造方法に関す
る。The present invention relates is a disadvantage of the magnetic powder used in the coating type high density magnetic recording medium, the cobalt-containing magnetic iron oxide was seed crystal more berthollide compound of Fe 2+ content Fe The present invention relates to a method for producing a cobalt-containing magnetic iron oxide powder having a hemimorphite coating, which has improved aging stability such as 2+ content, coercive force and saturation magnetization.
【０００２】[0002]
【従来の技術】塗布型高密度磁気記録媒体用磁性粉とし
ては、近年、高性能化のため高記録密度、高出力特性な
ど磁気特性の優れた、Ｆｅ2+含有量の多いベルトライド
核晶にＣｏ被覆したタイプの強磁性酸化鉄粉末がビデオ
テープ用の磁性材料として使用されるようになった。こ
のＦｅ2+含有量の多いベルトライド核晶にＣｏ被覆した
磁性酸化鉄粉末は、マグヘマイトやＦｅ2+含有量が１０
％以下であるベルトライドを核晶に用いた場合に比べて
１）飽和磁化量が高いためテープにした時の出力特性
が向上する、２）Ｆｅ2+含有量が多いことで黒色度の高
いテープができるため、塗膜厚を薄くすることによるコ
ストダウンが可能となる、３）電気伝導度が高いので、
電気抵抗を下げるために添加しているカーボンの添加量
を減らせるなど磁気記録媒体を作製する面での利点が多
い。しかしながら、酸化され易いＦｅ2+含有量が多いた
め、Ｆｅ2+含有量、保磁力及び飽和磁化量などが経時的
に劣化することが最大の欠点であった。2. Description of the Related Art In recent years, as a magnetic powder for a coating type high-density magnetic recording medium, a belt-ride nucleus having a high Fe 2+ content and excellent magnetic properties such as a high recording density and a high output characteristic for high performance has been recently developed. Ferromagnetic iron oxide powder of the type coated with Co has come to be used as a magnetic material for video tapes. The magnetic iron oxide powder coated with Co on the beltride nucleus crystal having a large Fe 2+ content has a maghemite or Fe 2+ content of 10%.
%) Compared with the case where a beltride of less than or equal to 1% is used as a nucleus crystal. 1) The output characteristics when a tape is improved due to a high saturation magnetization, and 2) High blackness due to a large Fe 2+ content. Since tape can be made, it is possible to reduce costs by reducing the thickness of the coating film. 3) Since electric conductivity is high,
There are many advantages in producing a magnetic recording medium, such as reducing the amount of carbon added to reduce electric resistance. However, the greatest drawback is that the Fe 2+ content, which is easily oxidized, deteriorates with time with respect to the Fe 2+ content, coercive force, saturation magnetization, and the like.
【０００３】そのＦｅ2+含有量の多いＣｏ被着磁性粉の
酸化防止の方法としては、Ｃｏ被着反応以降に、湿式工
程あるいは乾式工程において酸化幅を充分にとり、酸化
被膜層を形成させる方法がまず始めに検討されたがこの
方法では、経時安定性は不充分であり、又、特徴として
いた高飽和磁化量や黒色度が損なわれる問題があった。[0003] As a method of preventing oxidation of the Co-coated magnetic powder having a high content of Fe 2+, a method of forming an oxide film layer by taking a sufficient oxidation width in a wet process or a dry process after the Co deposition reaction. Although this method was first studied, there was a problem that the stability over time was insufficient and the characteristic high saturation magnetization and blackness were impaired.
【０００４】一方、別の方法として、Ｃｏ被覆層の上に
他金属による耐酸化防止膜を形成させる方法が開示され
た。例えば特開昭６３−４５１２９ではカルシウム−ケ
イ素共沈殿で被覆する方法、特開平２−８３２１９では
ケイ素化合物または、ケイ素化合物とアルミニウム、リ
ン、バナジウム、マンガン、ニッケル及び亜鉛等からな
る化合物層を形成させる方法、更に特開平２−２８０３
０１では下層がＺｎ、上層がＳｉ及びＡｌ、Ｃｏ，Ｚｒ
等による二重層によって被覆する方法などが開示された
が、これらの方法によって製造された磁性粉末において
も経時安定性においてまだ不充分であった。On the other hand, as another method, a method of forming an anti-oxidation film of another metal on a Co coating layer has been disclosed. For example, JP-A-63-45129 discloses a method of coating with calcium-silicon coprecipitation, and JP-A-2-83219 forms a compound layer comprising a silicon compound or a silicon compound and aluminum, phosphorus, vanadium, manganese, nickel, zinc or the like. Method, and further, JP-A-2-2803
01, the lower layer is Zn, and the upper layer is Si and Al, Co, Zr.
And the like. However, magnetic powders produced by these methods are still insufficient in stability over time.
【０００５】又、非磁性の金属を添加することによる飽
和磁化量の低下、更には磁気塗料中での分散性等の問題
があり、これらの特性と経時安定性の双方を満足するコ
バルト含有磁性酸化鉄粉末の製造が望まれていた。[0005] In addition, there are problems such as a decrease in the amount of saturation magnetization due to the addition of a non-magnetic metal and dispersibility in a magnetic paint, and a cobalt-containing magnetic material which satisfies both of these characteristics and stability over time. Production of iron oxide powder has been desired.
【０００６】[0006]
【発明が解決しようとする課題】Ｆｅ2+含有量の多いベ
ルトライド核晶にＣｏ被覆処理を行った磁性酸化鉄粉末
は、磁気特性的には利点が多いが、Ｆｅ2+含有量が多い
ことに起因して、酸化され易く、経時安定性が悪いとい
う欠点があった。そこで本発明は経時安定性改良のた
め、Ｃｏ被覆層の上に、耐酸化性に優れたヘミモルファ
イト被膜を形成させたコバルト含有酸化鉄粉末を提供し
ようとするものである。A magnetic iron oxide powder obtained by subjecting a beltride nucleus crystal having a large Fe 2+ content to a Co coating treatment has many advantages in magnetic properties, but has a large Fe 2+ content. For this reason, there is a drawback that they are easily oxidized and have poor stability over time. Therefore, the present invention aims to provide a cobalt-containing iron oxide powder in which a hemimorphite coating film having excellent oxidation resistance is formed on a Co coating layer in order to improve aging stability.
【０００７】[0007]
【課題を解決するための手段】本発明者らはＦｅ2+含有
量の多いベルトライド核晶にＣｏ被覆した磁性粉末の持
つ最大の欠点である経時安定性を改良すると共に、磁気
塗料中での分散性を損なわない磁性粉末の開発を進めた
結果、Ｃｏ被覆層の上に緻密で均一化したヘミモルファ
イト［Ｚｎ4Ｓｉ2Ｏ7（ＯＨ）2・Ｈ2Ｏ］からなる耐酸
化性の優れた被膜を形成した磁性粉末を製造することに
より本発明を完成させた。Means for Solving the Problems The present inventors have improved the aging stability, which is the greatest drawback of the magnetic powder in which Co is coated on a beltride nucleus crystal having a high Fe 2+ content, and improved the stability in magnetic paint. As a result of the development of a magnetic powder that does not impair the dispersibility of zirconia, the oxidation resistance of hemimorphite [Zn 4 Si 2 O 7 (OH) 2 .H 2 O] that is dense and uniform on the Co coating layer The present invention has been completed by producing a magnetic powder having a coating excellent in the above.
【０００８】そのヘミモルファイトの被膜を有するコバ
ルト含有磁性酸化鉄は次の如く製造される。The cobalt-containing magnetic iron oxide having the hemimorphite film is produced as follows.
【０００９】まず始めにＦｅ2+の含有量の多いベルトラ
イド化合物にＣｏ被覆処理を行う。本発明に使用される
ベルトライド化合物は、Ｆｅ2+含有量１０〜２１％（マ
グネタイトのＦｅ2+含有量は２２．８％）のものであれ
ばいずれも使用できる。具体的には、鉄酸化物単体でも
よいし、又、ゲーサイト反応時あるいはゲーサイト表面
にＰ，Ｓｉ，Ｚｎ，Ａｌ等の金属を添加あるいは被覆さ
れたものでもよい。又、Ｃｏ被覆処理は通常の方法で行
われる方法でよいが、Ｃｏ被覆時に用いるＣｏ及びＦｅ
2+の添加量は、核晶の重量基準に対し、Ｃｏ量は０．５
〜５ｗｔ％、Ｆｅ2+量は１〜１０ｗｔ％とするのが好ま
しい。First, a Co coating treatment is performed on a beltride compound having a high Fe 2+ content. Any of the beltride compounds used in the present invention can be used as long as the Fe2 + content is 10 to 21% (the Fe2 + content of magnetite is 22.8%). Specifically, it may be an iron oxide alone, or a material in which a metal such as P, Si, Zn, Al or the like is added or coated at the time of the goethite reaction or on the goethite surface. The Co coating treatment may be performed by a usual method.
The amount of 2+ added is 0.5% Co based on the weight of the nucleus.
Preferably, the content of Fe 2+ is set to 1 to 10 wt%.
【００１０】次に、ヘミモルファイト被膜の形成を行う
のであるが、Ｃｏ被覆処理に引き続き行ってもよいし、
あるいは一度乾燥した粉末を水分散させ行ってもよい。
このＣｏ被覆磁性粉末を含むスラリーのｐＨを９．５〜
１１の範囲を維持しながらＳｉ及びＺｎまたはＳｉ、Ｚ
ｎ及びＡｌの化合物を添加することにより、Ｃｏ被覆層
の上にこれらの化合物を水酸化物の形で沈着させ、引き
続き１２０〜２００℃の範囲で水熱処理を行うことによ
り、耐酸化性に優れたヘミモルファイトの被膜を形成す
ることができる。本発明においては、ｐＨ９．５〜１
１、好ましくは１０．０〜１０．５の範囲に維持しなが
ら、Ｓｉ及びＺｎまたはＳｉ、Ｚｎ及びＡｌの水酸化物
を沈着させた後、引き続き水熱処理を行う。添加される
ＺｎとＳｉの割合はモル比基準で１＜Ｚｎ／Ｓｉ＜３の
範囲である。それぞれの添加量は、コバルト含有磁性酸
化鉄に対し、Ｓｉ化合物はＳｉとして０．２〜０．８ｗ
ｔ％、Ｚｎ化合物はＺｎとして０．５〜４ｗｔ％、Ａｌ
化合物はＡｌとして０．０５〜０．５ｗｔ％である。ヘ
ミモルファイトの構造式はＺｎ4Ｓｉ2Ｏ7（ＯＨ）2・Ｈ
2Ｏで表される如く、ＺｎとＳｉのモル比は２であるの
で、Ｚｎ／Ｓｉのモル比を少なくとも１より大とし、か
つ、緻密で均一な被膜を形成させるためには、ＺｎＯの
等電点（ｐＨ９．３）よりｐＨを高い方に維持しておく
必要がある。又、Ａｌを０．０５〜０．５ｗｔ％の範囲
でＳｉ，Ｚｎと供に水酸化物を沈着させることにより、
ヘミモルファイトによる被膜の緻密化と均一性を更に高
めることができる。Next, a hemimorphite film is formed. The hemimorphite film may be formed after the Co coating process.
Alternatively, the powder once dried may be dispersed in water.
The pH of the slurry containing the Co-coated magnetic powder was adjusted to 9.5 to 9.5.
11 while maintaining the range of 11
By adding compounds of n and Al, these compounds are deposited on the Co coating layer in the form of a hydroxide, and subsequently subjected to hydrothermal treatment at a temperature in the range of 120 to 200 ° C., resulting in excellent oxidation resistance. A hemimorphite coating can be formed. In the present invention, pH 9.5 to 1
After the deposition of Si and Zn or hydroxides of Si, Zn and Al, while maintaining the temperature in the range of preferably 10.0 to 10.5, hydrothermal treatment is subsequently carried out. The ratio of Zn and Si to be added is in the range of 1 <Zn / Si <3 on a molar ratio basis. The amount of each addition is 0.2 to 0.8 w as Si with respect to cobalt-containing magnetic iron oxide.
t%, Zn compound is 0.5-4 wt% as Zn, Al
The compound is 0.05 to 0.5 wt% as Al. The structural formula of hemimorphite is Zn 4 Si 2 O 7 (OH) 2 .H
As represented by 2 O, the molar ratio of Zn to Si is 2, so that the molar ratio of Zn / Si should be at least greater than 1 and a dense and uniform film should be formed. It is necessary to maintain the pH higher than the electric point (pH 9.3). Further, by depositing a hydroxide with Al in the range of 0.05 to 0.5 wt% together with Si and Zn,
Densification and uniformity of the coating by hemimorphite can be further enhanced.
【００１１】Ｆｅ2+を含有するベルトライド化合物にＣ
ｏ被覆した磁性粉末の経時安定性を改良する方法とし
て、他金属による耐酸化防止膜を形成させる方法が開示
されていたことは、前述した通りである。その耐酸化防
止膜として用いられる元素としてはＳｉ，Ａｌ，Ｃａ，
Ｔｉ，Ｐ，Ｂａ，Ｍｎ，Ｎｉ及びＺｎ等が考えられ、こ
れらの元素の１種又は２種以上の化合物層を形成させる
ことで、経時安定性の改良はある程度までは可能と考え
られる。しかしながら本発明で使用されるような、従来
のものよりＦｅ2+含有量が多いベルトライド化合物を核
晶に用いる場合には、更に経時安定化を図る必要があっ
た。そこで本発明においては、粒子表面を単に金属の水
酸化物や酸化物で被覆するだけでなく、水酸化物層を沈
着させた後引き続き水熱処理を行うことにより、より結
晶性の強いヘミモルファイトの被膜を形成させ、従来の
ものに比べ優れた耐酸化防止膜を得ている。[0011] The beltride compound containing Fe 2+ contains C
As described above, a method for forming an anti-oxidation film made of another metal has been disclosed as a method for improving the temporal stability of the coated magnetic powder. The elements used as the anti-oxidation film include Si, Al, Ca,
Ti, P, Ba, Mn, Ni, Zn and the like are considered, and it is considered that the stability over time can be improved to some extent by forming one or more compound layers of these elements. However, when a beltride compound having a higher Fe 2+ content than the conventional one is used for a nucleus crystal as used in the present invention, it is necessary to further stabilize with time. Therefore, in the present invention, the hemimorphite having higher crystallinity is obtained by not only coating the surface of the particles with a metal hydroxide or oxide but also performing a hydrothermal treatment after depositing a hydroxide layer. To form an anti-oxidation film superior to the conventional one.
【００１２】後述する実施例と比較例の結果では、特許
請求の範囲に記載された組成のＳｉとＺｎからなる化合
物層を形成させても、水熱処理による結晶化を行わなか
ったものは、水熱処理を行ったものに比較して劣った酸
化防止効果しか得られていない。この結果は、水酸化物
層を沈着させた後に引き続き水熱処理を行うことが、本
発明の所定の効果を得るために必須の要件であることを
示すものである。In the results of Examples and Comparative Examples described below, it was found that even if a compound layer composed of Si and Zn having the composition described in the claims was formed, the crystallization was not performed by hydrothermal treatment. Only an antioxidant effect inferior to that of the heat treatment was obtained. This result indicates that the subsequent hydrothermal treatment after the deposition of the hydroxide layer is an essential requirement for obtaining the desired effects of the present invention.
【００１３】Ｓｉ化合物との化合物を形成しない元素、
例えば、Ｔｉ，Ｐ，Ｂａ，Ｎｉ，Ｃｕ，Ｚｒなどを用い
る場合、更にはＳｉとの化合物を形成するＭｎ，Ｍｇな
どであっても１２０〜２００℃の水熱処理で結晶化しな
いものについては、所望の酸化防止効果が得られないこ
とが分かった。An element which does not form a compound with the Si compound,
For example, when Ti, P, Ba, Ni, Cu, Zr, etc. are used, and Mn, Mg, etc., which form a compound with Si, do not crystallize by a hydrothermal treatment at 120 to 200 ° C. It was found that the desired antioxidant effect could not be obtained.
【００１４】水熱処理で添加した全てのＳｉとＺｎが結
晶化するわけではなく、一部のＺｎはＣｏ被着層内に拡
散してゆきＺｎフェライトを形成することも充分あり得
ると考えられ、それによる酸化防止効果も一部含まれて
いると推定される。事実Ｚｎ，Ｃａ，Ｍｎ，Ｃｕ等フェ
ライトを形成できる元素とＳｉとの組み合わせで処理し
たものは、フェライトの形成ができない元素の場合と比
較して飽和磁化量の低下幅が小さくなっていた。Not all of the Si and Zn added by the hydrothermal treatment are crystallized, and it is considered that some of the Zn may diffuse into the Co-deposited layer to form Zn ferrite, It is presumed that some of the antioxidant effects thereby are also included. In fact, when treated with a combination of Si and an element capable of forming ferrite, such as Zn, Ca, Mn, and Cu, the decrease in the saturation magnetization was smaller than in the case of an element capable of forming no ferrite.
【００１５】又ＳｉとＺｎにＡｌを併用することで酸化
防止効果が更に大きくなる傾向も認められた。これはＡ
ｌを併用することでＳｉとＺｎの生成化合物が微細化さ
れ、その後の水熱処理で形成されるヘミモルファイト被
膜の緻密化と均一性の向上が更に高まるためと推定され
る。It was also observed that the use of Al in combination with Si and Zn tended to further increase the antioxidant effect. This is A
It is presumed that when l is used together, the resulting compound of Si and Zn is miniaturized, and the densification and uniformity of the hemimorphite film formed by the subsequent hydrothermal treatment are further improved.
【００１６】ＳｉとＺｎの添加量の比率もヘミモルファ
イトの形成という観点から大切なファクターであり、モ
ル比基準で少なくとも１＜Ｚｎ／Ｓｉ＜３の範囲でない
と顕著な酸化防止効果が認められなかった。これはヘミ
モルファイト組成でのＺｎ／Ｓｉモル比である２前後の
範囲（１より大で３より小）が最も酸化防止効果が大き
いためと考えられる。又、ベルトライド化合物の核晶を
用いないＳｉとＺｎのみで調べた結果であるが、ヘミモ
ルファイトのＸ線回折ピークの強度はＺｎとＳｉ組成比
に対応していることを確認している。The ratio of the added amounts of Si and Zn is also an important factor from the viewpoint of the formation of hemimorphite, and a remarkable antioxidant effect is recognized unless the molar ratio is at least in the range of 1 <Zn / Si <3. Did not. This is considered to be because the Zn / Si molar ratio in the hemimorphite composition is in the range of around 2 (greater than 1 and smaller than 3), and the antioxidant effect is greatest. In addition, it is a result of examining only Si and Zn without using a nucleus of a beltride compound, and it is confirmed that the intensity of the X-ray diffraction peak of hemimorphite corresponds to the Zn and Si composition ratio. .
【００１７】次にＳｉ，Ｚｎの添加量についてである
が、ＳｉとＺｎの比率が上記の範囲内にあっても、添加
量が少なすぎたり多すぎたりする場合には弊害が出る。
すなわち磁性粉の粒子表面が充分に被覆されるだけの処
理量は必要であり、Ｓｉは０．２〜０．８ｗｔ％の範
囲、Ｚｎは０．５〜４ｗｔ％の範囲内に調節する必要が
ある。又、これらにＡｌ添加を組み合わせる場合Ａｌは
０．０５〜０．５ｗｔ％の範囲内に調節する必要があ
る。上記範囲より添加量が少ない場合、酸化防止効果が
小さくなるだけでなく水熱処理でのＨｃ発現性向上効果
が弱まる現象が認められる。一方上記範囲より添加量が
多い場合は、酸化防止効果は添加量が少なすぎる場合ほ
どではないが、やはり低下する傾向が認められ、又、Ｈ
ｃ発現性向上効果も弱まる。これは水熱処理で生じてい
る現象を考えることで理解される。Next, regarding the addition amounts of Si and Zn, even if the ratio of Si and Zn is within the above range, if the addition amount is too small or too large, adverse effects will occur.
That is, it is necessary to have a treatment amount sufficient to sufficiently cover the particle surface of the magnetic powder, and it is necessary to adjust Si to a range of 0.2 to 0.8 wt% and Zn to a range of 0.5 to 4 wt%. is there. When these are combined with the addition of Al, it is necessary to adjust the Al content in the range of 0.05 to 0.5 wt%. When the addition amount is smaller than the above range, not only the antioxidant effect is reduced, but also the phenomenon that the effect of improving Hc expression by hydrothermal treatment is weakened is observed. On the other hand, when the addition amount is larger than the above range, the antioxidant effect is not so small as when the addition amount is too small, but also tends to decrease, and
The effect of improving the expression of c also weakens. This can be understood by considering the phenomenon occurring in the hydrothermal treatment.
【００１８】すなわちＣｏ被着磁性粉に水熱処理を施す
と、被着層の結晶性向上だけではなく溶解析出反応が生
じてＣｏ，Ｆｅ2+及びＦｅ3+のスピネル結晶構造下での
組み替えが活発となり、強磁性コバルトフェライト組成
か若しくはそれに類似する組成が均一に形成され、それ
によりＨｃ発現性の向上が生じると考えられる。しかし
同一の水熱処理を行ってもＳｉ，Ｚｎ，Ａｌ等の被覆量
が少なすぎると溶解析出反応が激しくなり、被着層のみ
にとどまらず核晶も含めた反応になり、特に水熱処理温
度の高い場合には粒子形態が針状高軸比のものからずん
ぐりした低軸比のものに変化することもある。従ってＨ
ｃ発現性向上幅が小さくなるのは、被着層の結晶の乱れ
と同時に形状異方性の低下によるものと推定される。That is, when the hydrothermal treatment is performed on the Co-coated magnetic powder, not only the crystallinity of the deposited layer is improved but also a dissolution precipitation reaction occurs, and the rearrangement of Co, Fe 2+, and Fe 3+ under the spinel crystal structure can be achieved. It is considered that the composition becomes active and a ferromagnetic cobalt ferrite composition or a composition similar thereto is formed uniformly, thereby improving the Hc expression. However, even when the same hydrothermal treatment is performed, if the coating amount of Si, Zn, Al, etc. is too small, the dissolution and precipitation reaction becomes intense, resulting in a reaction involving not only the deposited layer but also nuclei, and especially the When the particle size is high, the particle morphology may change from a needle-like high-axis ratio to a stubby low-axis ratio. Therefore H
It is presumed that the reason why the width of improvement in c expression is small is that the crystal of the adhered layer is disordered and the shape anisotropy is reduced at the same time.
【００１９】一方Ｓｉ，Ｚｎ，Ａｌ等の被覆量が多すぎ
る場合、溶解析出反応の抑制効果が大きすぎて被着層の
結晶性向上等の効果が小さくなりＨｃ発現性の向上幅が
小さくなる。同時に被着層の結晶性が弱く酸化に対して
脆弱となるために酸化防止効果もやや弱まると考えら
れ、Ｓｉ，Ｚｎ，Ａｌ等でいくらコーティングしてもそ
の下の被着層の結晶性が強くないと酸化安定性に対して
は不充分と考えられる。On the other hand, if the coating amount of Si, Zn, Al or the like is too large, the effect of suppressing the dissolution / precipitation reaction is too large, and the effect of improving the crystallinity of the deposited layer is reduced, and the improvement in Hc expression is reduced. . At the same time, it is considered that the crystallinity of the adhered layer is weak and the film is vulnerable to oxidation, so that the antioxidant effect is somewhat weakened. If it is not strong, the oxidation stability is considered to be insufficient.
【００２０】Ａｌについては添加量が０．５ｗｔ％をこ
えると磁気記録媒体にした時の配向特性劣化が生じる。
元々Ａｌについては単独処理の場合０．５ｗｔ％以下で
も配向特性の劣化が認められており、それは生成するＡ
ｌの水酸化物が大きいため粒子間に接着剤的な働きをし
てしまうためと推定される。一方ＡｌをＳｉ，Ｚｎ等と
組み合わせると０．５ｗｔ％位までは配向特性の劣化は
生じないが、それはＡｌがＳｉ，Ｚｎの生成化合物の微
細化をしているだけでなくＡｌ自身も微細化されるため
ではないかと考えられる。If the amount of Al exceeds 0.5 wt%, the orientation characteristics of the magnetic recording medium deteriorate.
Originally, with respect to Al, even in the case of a single treatment, deterioration of the orientation characteristics was recognized even at 0.5 wt% or less.
It is presumed that because the hydroxide of 1 is large, it acts as an adhesive between the particles. On the other hand, when Al is combined with Si, Zn, etc., the deterioration of the orientation characteristics does not occur up to about 0.5 wt%, but this is because Al not only makes the compound of forming Si and Zn fine, but also makes Al itself fine. It is thought that it is to be done.
【００２１】Ｓｉ，Ｚｎ，Ａｌ処理量は経時安定性だけ
でなく磁性粉末の分散性に関する一指標である脂肪酸吸
着量にも大きく影響する。Ｓｉ，Ａｌについては脂肪酸
吸着量を減らす方向に、又Ｚｎは脂肪酸吸着量を増やす
方向に作用する。吸着特性は磁性粉の塗料分散性に影響
を及ぼし、少なすぎると分散不良となり逆に多すぎると
塗料の凝集が強くなりすぎるので適度な吸着量のレベル
に調節する必要がある。従って、Ｓｉ，Ｚｎ，Ａｌ処理
量は経時安定性と吸着特性の両方を満足する条件に設定
する必要があり、一般的にいえば脂肪酸の吸着量として
は１５〜４０ｍｇ／ｇの範囲とすることが好ましい。The amount of Si, Zn, and Al treatment greatly affects not only the stability with time but also the amount of fatty acid adsorbed, which is one index relating to the dispersibility of the magnetic powder. Si and Al act in a direction to decrease the fatty acid adsorption amount, and Zn acts in a direction to increase the fatty acid adsorption amount. The adsorption characteristics affect the dispersibility of the magnetic powder in the paint. If the amount is too small, the dispersion is poor, and if the amount is too large, the agglomeration of the paint becomes too strong. Therefore, it is necessary to adjust the adsorption amount to an appropriate level. Therefore, it is necessary to set the treatment amounts of Si, Zn, and Al so as to satisfy both the stability over time and the adsorption characteristics. Generally speaking, the adsorption amount of the fatty acid should be in the range of 15 to 40 mg / g. Is preferred.
【００２２】そのＳｉ及びＺｎまたはＳｉ，Ｚｎ及びＡ
ｌの処理は通常下記の如く行われる。The Si and Zn or Si, Zn and A
The processing of 1 is usually performed as follows.
【００２３】Ｃｏ被着反応終了後スラリーを濾過水洗し
余剰のアルカリと雑塩を除去する。次にスラリー分散化
を行い、Ｃｏ被着磁性酸化鉄粒子表面にＳｉ及びＺｎか
らなる化合物或はＳｉ，Ｚｎ及びＡｌからなる化合物の
水酸化物層を沈着させる。After the completion of the Co deposition reaction, the slurry is filtered and washed with water to remove excess alkali and miscellaneous salts. Next, slurry dispersion is performed to deposit a hydroxide layer of a compound composed of Si and Zn or a compound composed of Si, Zn and Al on the surface of the magnetic iron oxide particles coated with Co.
【００２４】Ｓｉを含む化合物としてはケイ酸ソーダ、
３号水ガラス、コロイダルシリカ等を用いることができ
る。Ｚｎを含む化合物としては硫酸亜鉛、硝酸亜鉛、酸
化亜鉛等が、Ａｌを含む化合物としては硫酸アルミニウ
ム、硝酸アルミニウム、アルミン酸ソーダ等がある。所
定量のＳｉ，Ｚｎ或はＡｌを添加するが、その添加順序
は任意である。好ましくはＳｉを含む化合物を先に添加
し、次にＺn或はＺnとＡｌを含む化合物をＮａＯＨ等の
水酸化アルカリとｐＨ９．５〜１１を維持するよう同時
添加する方法がよい。Examples of the compound containing Si include sodium silicate,
No. 3 water glass, colloidal silica, or the like can be used. Compounds containing Zn include zinc sulfate, zinc nitrate, zinc oxide and the like, and compounds containing Al include aluminum sulfate, aluminum nitrate, sodium aluminate and the like. A predetermined amount of Si, Zn or Al is added, but the order of addition is arbitrary. Preferably, a compound containing Si is added first, and then Zn or a compound containing Zn and Al is added simultaneously with an alkali hydroxide such as NaOH so as to maintain pH 9.5 to 11.
【００２５】引き続き行われる水熱処理条件について述
べると、上述したＳｉ及びＺｎまたはＳｉ，Ｚｎ及びＡ
ｌとの水酸化物を沈着させｐＨ９．５〜１１を維持した
まま水熱処理を行うことが好ましく、その温度は１２０
〜２００℃、好ましくは１３０〜１８０℃であり、処理
時間は通常１〜５時間である。このうち最も重要なの
は、前述した如くｐＨをＺｎＯの等電点９．３より高い
ｐＨ９．５〜１１、好ましくは１０．０〜１０．５を維
持することで、これによりＳｉ及びＺn、またはＳｉ，
Ｚｎ及びＡｌが緻密で均一なヘミモルファイトの被膜を
形成することが出来る。又ｐＨ１１以上とした場合、そ
れ以上の効果が望めないだけでなく、それ以降に行われ
る水洗工程に負荷がかかり好ましくない。又、水熱処理
温度は１２０℃以下ではヘミモルファイトの結晶化が弱
く、又、２００℃以上の場合はそれ以上の効果が望めな
い。The hydrothermal treatment conditions to be performed subsequently are as follows: Si and Zn or Si, Zn and A
It is preferable to perform a hydrothermal treatment while maintaining a pH of 9.5 to 11 by depositing a hydroxide with 1 l.
To 200 ° C, preferably 130 to 180 ° C, and the treatment time is usually 1 to 5 hours. The most important of these is to maintain the pH at 9.5 to 11, preferably 10.0 to 10.5, higher than the isoelectric point of ZnO of 9.3, as described above, whereby Si and Zn, or Si, are maintained. ,
Zn and Al can form a dense and uniform coating of hemimorphite. When the pH is 11 or more, not only the further effect cannot be expected, but also the washing step performed thereafter is undesirably burdened. When the hydrothermal treatment temperature is lower than 120 ° C., the crystallization of hemimorphite is weak, and when the temperature is higher than 200 ° C., no further effect can be expected.
【００２６】以下に実施例を挙げて本発明をさらに詳細
に説明する。以下の実施例は単に例示のために記すもの
であり、発明の範囲がこれらによって制限されるもので
はない。Hereinafter, the present invention will be described in more detail with reference to examples. The following examples are provided for illustrative purposes only, and are not intended to limit the scope of the invention.
【００２７】実施例１ 針状ベルトライド酸化鉄化合物［長軸径０．２３μｍ、
短軸径０．０３μｍ、比表面積３４ｍ2／ｇ、Ｆｅ2+含
有量１８ｗｔ％、保磁力（Ｈｃ）３７０ Ｏｅ、飽和磁
化量（σｓ）８０ｅｍｕ／ｇ］１５０ｇを強力な機械的
撹拌で６００ｍｌの水に分散させた。そのスラリーを小
型ステンレス製反応槽に移し、ついで４００ｇ／リット
ルに溶解した苛性ソーダ３００ミリリットルを添加し、
空気による酸化を防ぐために窒素ガスを吹き込みながら
硫酸コバルト（ＣｏＳＯ4・７Ｈ2Ｏ）１１．８ｇと硫酸
第一鉄（ＦｅＳＯ4・７Ｈ2Ｏ）２８．５ｇを純水３５０
ミリリットルに溶解した水溶液を加え、３５℃にて３時
間撹拌を続けた。ついでこのスラリーに窒素ガスの吹き
込みを続けながらスラリーを９５℃まで加熱し４時間撹
拌した。このＣｏ被覆反応が終わったスラリーを濾過、
水洗した後、メタケイ酸ソーダ水溶液（ＳｉＯ2／Ｎａ2
Ｏモル比＝１：１，ＳｉＯ2として７６．６ｇ／リット
ル）２３．０ミリリットル添加し、次に硫酸亜鉛水溶液
（Ｚｎとして２０ｇ／リットル）１８４ミリリットルと
ＮａＯＨとの同時中和でスラリーのｐＨを１０．０〜１
０．５に保ちつつ３０分かけて滴下した。（Ｃｏ被着粉
に対しＳｉとして０．５５ｗｔ％、Ｚｎとして２．３０
ｗｔ％）処理したスラリーをオートクレーブに入れて撹
拌しながら１６０℃で３時間加熱処理した。その後スラ
リーをオートクレーブより取り出し濾過、水洗し５５℃
で３時間乾燥し磁性粉サンプル（Ａ）を作製した。Example 1 Needle-shaped belt oxide iron oxide compound [major axis diameter 0.23 μm,
0.03 μm of minor axis diameter, specific surface area of 34 m 2 / g, Fe 2+ content of 18 wt%, coercive force (Hc) of 370 Oe, saturation magnetization (σs) of 80 emu / g] of 150 g with strong mechanical stirring. Dispersed in water. The slurry was transferred to a small stainless steel reaction tank, and then 300 ml of caustic soda dissolved at 400 g / liter was added.
Cobalt sulfate while blowing nitrogen gas to prevent oxidation by air (CoSO 4 · 7H 2 O) 11.8g of ferrous sulfate (FeSO 4 · 7H 2 O) 28.5g of pure water 350
An aqueous solution dissolved in milliliters was added and stirring was continued at 35 ° C. for 3 hours. Next, the slurry was heated to 95 ° C. while continuing to blow nitrogen gas into the slurry, and stirred for 4 hours. The slurry after the Co coating reaction is filtered,
After washing with water, an aqueous solution of sodium metasilicate (SiO 2 / Na 2
O mole ratio = 1: 1, 23.0 ml of 76.6 g / l as SiO 2 were added, and then the pH of the slurry was simultaneously neutralized with 184 ml of an aqueous solution of zinc sulfate (20 g / l as Zn) and NaOH. 10.0-1
The solution was added dropwise over 30 minutes while maintaining at 0.5. (0.55 wt% as Si and 2.30 as Zn with respect to Co adhered powder)
(wt%) The treated slurry was placed in an autoclave and heated at 160 ° C. for 3 hours with stirring. Thereafter, the slurry was taken out of the autoclave, filtered, washed with water, and 55 ° C.
For 3 hours to prepare a magnetic powder sample (A).
【００２８】実施例２ 実施例１において、メタケイ酸ソーダの添加量をＳｉと
して０．２７ｗｔ％に又硫酸亜鉛の添加量をＺｎとして
１．１１ｗｔ％とした以外は実施例１の場合と同様にし
て磁性粉サンプル（Ｂ）を作製した。Example 2 The procedure of Example 1 was repeated except that the amount of sodium metasilicate was changed to 0.27 wt% as Si and the amount of zinc sulfate was changed to 1.11 wt% as Zn. Thus, a magnetic powder sample (B) was prepared.
【００２９】実施例３ 実施例１において、硫酸亜鉛の添加量をＺｎとして３．
３８ｗｔ％とした以外は実施例１の場合と同様にして磁
性粉サンプル（Ｃ）を作製した。Example 3 In Example 1, the addition amount of zinc sulfate was changed to Zn.
A magnetic powder sample (C) was prepared in the same manner as in Example 1 except that the content was 38 wt%.
【００３０】実施例４ 実施例１において、Ｓｉ，Ｚｎに加えてＡｌを組み合わ
せた以外は実施例１の場合と同様にして磁性粉サンプル
（Ｄ）を作製した。Ａｌは０．２ｗｔ％分を硫酸アルミ
水溶液で添加した。Example 4 A magnetic powder sample (D) was prepared in the same manner as in Example 1 except that Al was combined in addition to Si and Zn. Al was added in an amount of 0.2 wt% with an aluminum sulfate aqueous solution.
【００３１】比較例１ 実施例１において、Ｚｎの代わりにＣａを用いた以外は
実施例１と同様にして磁性粉サンプル（Ｅ）を作製し
た。Ｃａは１．２５ｗｔ％分を酢酸カルシウム水溶液で
添加した。Comparative Example 1 A magnetic powder sample (E) was prepared in the same manner as in Example 1, except that Ca was used instead of Zn. 1.25 wt% of Ca was added with an aqueous solution of calcium acetate.
【００３２】比較例２ 実施例１において、Ｚｎを添加せずにオートクレーブに
よる加熱処理を行い、水熱処理後にＺｎを添加処理した
以外は実施例１と同様にして磁性粉サンプル（Ｆ）を作
製した。Comparative Example 2 A magnetic powder sample (F) was prepared in the same manner as in Example 1, except that the heat treatment was performed by an autoclave without adding Zn, and the Zn was added after the hydrothermal treatment. .
【００３３】比較例３ 実施例１において、メタケイ酸ソーダの添加量をＳｉと
して０．１ｗｔ％に又硫酸亜鉛の添加量をＺｎとして
０．３ｗｔ％とした以外は実施例１と同様にして磁性粉
サンプル（Ｇ）を作製した。Comparative Example 3 A magnetic material was prepared in the same manner as in Example 1 except that the amount of sodium metasilicate was changed to 0.1 wt% as Si and the amount of zinc sulfate was changed to 0.3 wt% as Zn. A powder sample (G) was prepared.
【００３４】比較例４ 実施例１において、硫酸亜鉛の添加量をＺｎとして０．
５５ｗｔ％とした以外は実施例１と同様にして磁性粉サ
ンプル（Ｈ）を作製した。COMPARATIVE EXAMPLE 4 In Example 1, the amount of zinc sulfate added was set to 0.1 as Zn.
A magnetic powder sample (H) was prepared in the same manner as in Example 1 except that the content was 55 wt%.
【００３５】比較例５ 実施例１において、硫酸亜鉛水溶液とＮａＯＨとの同時
中和する際のｐＨを８．０とした以外は実施例１と同様
にして磁性粉サンプル（Ｉ）を作製した。Comparative Example 5 A magnetic powder sample (I) was prepared in the same manner as in Example 1 except that the pH at the time of simultaneously neutralizing the aqueous zinc sulfate solution and NaOH was changed to 8.0.
【００３６】実施例１〜４及び比較例１〜５の作成条件
及び測定結果を表−１に示した。尚、測定条件は次の通
りである。The preparation conditions and measurement results of Examples 1 to 4 and Comparative Examples 1 to 5 are shown in Table 1. The measurement conditions are as follows.
【００３７】Ｓｉ，Ｚｎ，Ａｌ及びＣａ含有量は蛍光Ｘ
線分析により、又Ｆｅ2+含有量は化学分析法にて測定し
た。The content of Si, Zn, Al and Ca is determined by the fluorescent X
The Fe 2+ content was measured by line analysis and the chemical analysis method.
【００３８】磁気特性は「振動試料型磁力計ＶＳＭ−
３」（東英工業（株）製）にて測定した。The magnetic characteristics are described in "Vibration sample type magnetometer VSM-
3 "(manufactured by Toei Industry Co., Ltd.).
【００３９】脂肪酸吸着量の測定は次の如く行った。コ
バルト含有磁性酸化鉄粉末６ｇとメチルエルチケトン：
トルエン：シクロヘキサノン＝２：２：１の混合溶媒に
脂肪酸含有率２％になる様に作製した混合液１４ｇとを
混合し、振とう機にて２４時間振とうした後、遠心分離
により上澄液を分取し、脂肪酸量を定量分析する。加え
た脂肪酸量と分析量とから、磁性粉に吸着された脂肪酸
量を算出した。The measurement of the fatty acid adsorption amount was performed as follows. 6 g of cobalt-containing magnetic iron oxide powder and methyl elketone:
A mixture of toluene: cyclohexanone = 2: 2: 1 and 14 g of a mixture prepared so as to have a fatty acid content of 2% are mixed, shaken with a shaker for 24 hours, and then centrifuged to separate the supernatant. And quantitatively analyze the amount of fatty acids. From the amount of fatty acid added and the amount of analysis, the amount of fatty acid adsorbed on the magnetic powder was calculated.
【００４０】[0040]
【表１】 [Table 1]
【００４１】[0041]
【発明の効果】以上説明したように本発明によれば、Ｆ
ｅ2+含有量１０〜２１％のベルトライド化合物を核晶と
し、その表面をＦｅ2+を含むコバルト化合物で被覆した
Ｆｅ2+含有量の多い磁性酸化鉄粉末が、酸化による経時
変化で保磁力や飽和磁化量が低下するのを防ぐことがで
き、磁気的、化学的に安定な磁性粉を得ることができ
る。従って、ベルトライド化合物を核晶としたＣｏ被着
粉の特徴である高飽和磁化量、高Ｆｅ2+含有量ひいては
磁気記録媒体とした時の高出力特性、塗膜の薄膜化によ
るコストダウン等の利点を充分に発揮させることができ
る。As described above, according to the present invention, F
A magnetic iron oxide powder containing a large amount of Fe 2+ , whose core crystal is a beltride compound having an e 2+ content of 10 to 21% and whose surface is coated with a cobalt compound containing Fe 2+ , is maintained with the aging due to oxidation. It is possible to prevent the magnetic force and the saturation magnetization from decreasing, and to obtain magnetically and chemically stable magnetic powder. Therefore, high saturation magnetization, high Fe 2+ content, which is a characteristic of Co-coated powder using a beltlide compound as a nucleus, high output characteristics when used as a magnetic recording medium, cost reduction by thinning the coating film, etc. The advantage of can be fully exhibited.
フロントページの続き (72)発明者 上西 利明 山口県宇部市大字小串1978番地の25 チ タン工業株式会社内 (72)発明者 篠田 宏 山口県宇部市大字小串1978番地の25 チ タン工業株式会社内 (56)参考文献 特開 平２−255538（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01F 1/09 - 1/11 B22F 1/02 C01G 49/00 G11B 5/706 Continuing from the front page (72) Inventor Toshiaki Uenishi 2578 Kogushi, 1978 Kogushi, Ube City, Yamaguchi Prefecture Inside (72) Inventor Hiroshi Shinoda 25 Chitan Kogyo Co., Ltd. 1978 Kogushi, Ube City, Yamaguchi Prefecture (56) References JP-A-2-255538 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H01F 1/09-1/11 B22F 1/02 C01G 49/00 G11B 5/706
Claims (2)
トライド化合物を核晶とし、その表面をＦｅ2+を含むＣ
ｏ化合物で被覆した粒子の表面に、該Ｃｏ被覆磁性粉末
を含むスラリーのｐＨを９．５〜１１の範囲を維持しな
がら、Ｓｉ及びＺｎまたはＳｉ、Ｚｎ及びＡｌからなる
化合物の水酸化物層を沈着させ、引き続き１２０〜２０
０℃の範囲で水熱処理を行うことによりヘミモルファイ
トの被膜を形成させるコバルト含有磁性酸化鉄粉末の製
造方法であって、ＺｎとＳｉの割合がモル比基準で１＜
Ｚｎ／Ｓｉ＜３の範囲であり、コバルト含有磁性酸化鉄
に対し、Ｓｉ化合物の添加量がＳｉとして０．２〜０．
８ｗｔ％、Ｚｎ化合物の添加量がＺｎとして０．５〜４
ｗｔ％、Ａｌ化合物の添加量がＡｌとして０．０５〜
０．５ｗｔ％である製造方法。1. A beltride compound having an Fe 2+ content of 10 to 21% is used as a nucleus crystal, and the surface thereof is made of C 2 containing Fe 2+.
a hydroxide layer of Si and Zn or a compound comprising Si, Zn and Al, while maintaining the pH of the slurry containing the Co-coated magnetic powder in the range of 9.5 to 11 on the surface of the particles coated with the compound. And then 120 to 20
A method for producing a cobalt-containing magnetic iron oxide powder in which a hemimorphite film is formed by performing a hydrothermal treatment in a range of 0 ° C., wherein the ratio of Zn to Si is 1 <on a molar ratio basis.
Zn / Si <3, and the amount of the Si compound added to the cobalt-containing magnetic iron oxide is 0.2 to 0.1 as Si.
8 wt%, and the amount of Zn compound added is 0.5 to 4 as Zn.
wt%, the amount of the Al compound added is 0.05 to
Manufacturing method which is 0.5 wt%.
１記載の製造方法。2. The production method according to claim 1, wherein the pH is 10.0 to 10.5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18389593A JP3253768B2 (en) | 1993-07-26 | 1993-07-26 | Method for producing cobalt-containing magnetic iron oxide having hemimorphite coating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18389593A JP3253768B2 (en) | 1993-07-26 | 1993-07-26 | Method for producing cobalt-containing magnetic iron oxide having hemimorphite coating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0745415A JPH0745415A (en) | 1995-02-14 |
| JP3253768B2 true JP3253768B2 (en) | 2002-02-04 |
Family
ID=16143698
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18389593A Expired - Fee Related JP3253768B2 (en) | 1993-07-26 | 1993-07-26 | Method for producing cobalt-containing magnetic iron oxide having hemimorphite coating |
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| Country | Link |
|---|---|
| JP (1) | JP3253768B2 (en) |
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1993
- 1993-07-26 JP JP18389593A patent/JP3253768B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH0745415A (en) | 1995-02-14 |
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