JPH0261418B2 - - Google Patents
Info
- Publication number
- JPH0261418B2 JPH0261418B2 JP59175402A JP17540284A JPH0261418B2 JP H0261418 B2 JPH0261418 B2 JP H0261418B2 JP 59175402 A JP59175402 A JP 59175402A JP 17540284 A JP17540284 A JP 17540284A JP H0261418 B2 JPH0261418 B2 JP H0261418B2
- Authority
- JP
- Japan
- Prior art keywords
- barium
- barium ferrite
- precursor
- magnetic recording
- ions
- 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
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 claims description 69
- 239000000843 powder Substances 0.000 claims description 45
- 239000002243 precursor Substances 0.000 claims description 34
- 239000002245 particle Substances 0.000 claims description 33
- 239000007864 aqueous solution Substances 0.000 claims description 24
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 claims description 24
- 229910001626 barium chloride Inorganic materials 0.000 claims description 24
- 150000002500 ions Chemical class 0.000 claims description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 229910001422 barium ion Inorganic materials 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 229910052732 germanium Inorganic materials 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 229910052738 indium Inorganic materials 0.000 claims description 4
- 229910052748 manganese Inorganic materials 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 238000006467 substitution reaction Methods 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052725 zinc Inorganic materials 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 description 36
- 238000010304 firing Methods 0.000 description 16
- 239000002244 precipitate Substances 0.000 description 11
- 238000000635 electron micrograph Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 230000005415 magnetization Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000001027 hydrothermal synthesis Methods 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000010955 niobium Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 2
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 2
- 230000005347 demagnetization Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 2
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- QDZRBIRIPNZRSG-UHFFFAOYSA-N titanium nitrate Chemical compound [O-][N+](=O)O[Ti](O[N+]([O-])=O)(O[N+]([O-])=O)O[N+]([O-])=O QDZRBIRIPNZRSG-UHFFFAOYSA-N 0.000 description 2
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 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
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical class [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 1
- 229910021583 Cobalt(III) fluoride Inorganic materials 0.000 description 1
- 229910021594 Copper(II) fluoride Inorganic materials 0.000 description 1
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 1
- 229910001047 Hard ferrite Inorganic materials 0.000 description 1
- 229910021380 Manganese Chloride Inorganic materials 0.000 description 1
- GLFNIEUTAYBVOC-UHFFFAOYSA-L Manganese chloride Chemical compound Cl[Mn]Cl GLFNIEUTAYBVOC-UHFFFAOYSA-L 0.000 description 1
- XURCIPRUUASYLR-UHFFFAOYSA-N Omeprazole sulfide Chemical compound N=1C2=CC(OC)=CC=C2NC=1SCC1=NC=C(C)C(OC)=C1C XURCIPRUUASYLR-UHFFFAOYSA-N 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- WNPMJIKMURUYFG-UHFFFAOYSA-N [N+](=O)([O-])[O-].[Ge+2].[N+](=O)([O-])[O-] Chemical compound [N+](=O)([O-])[O-].[Ge+2].[N+](=O)([O-])[O-] WNPMJIKMURUYFG-UHFFFAOYSA-N 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 1
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 description 1
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 1
- ISFLYIRWQDJPDR-UHFFFAOYSA-L barium chlorate Chemical compound [Ba+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O ISFLYIRWQDJPDR-UHFFFAOYSA-L 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 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
- BSUSEPIPTZNHMN-UHFFFAOYSA-L cobalt(2+);diperchlorate Chemical compound [Co+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O BSUSEPIPTZNHMN-UHFFFAOYSA-L 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- IQYVXTLKMOTJKI-UHFFFAOYSA-L cobalt(ii) chlorate Chemical compound [Co+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O IQYVXTLKMOTJKI-UHFFFAOYSA-L 0.000 description 1
- YCYBZKSMUPTWEE-UHFFFAOYSA-L cobalt(ii) fluoride Chemical compound F[Co]F YCYBZKSMUPTWEE-UHFFFAOYSA-L 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- GWFAVIIMQDUCRA-UHFFFAOYSA-L copper(ii) fluoride Chemical compound [F-].[F-].[Cu+2] GWFAVIIMQDUCRA-UHFFFAOYSA-L 0.000 description 1
- YRNNKGFMTBWUGL-UHFFFAOYSA-L copper(ii) perchlorate Chemical compound [Cu+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O YRNNKGFMTBWUGL-UHFFFAOYSA-L 0.000 description 1
- IJCCOEGCVILSMZ-UHFFFAOYSA-L copper;dichlorate Chemical compound [Cu+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O IJCCOEGCVILSMZ-UHFFFAOYSA-L 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 229960003280 cupric chloride Drugs 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- TWFKOYFJBHUHCH-UHFFFAOYSA-K diperchloryloxyindiganyl perchlorate Chemical compound [In+3].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O TWFKOYFJBHUHCH-UHFFFAOYSA-K 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- GGJOARIBACGTDV-UHFFFAOYSA-N germanium difluoride Chemical compound F[Ge]F GGJOARIBACGTDV-UHFFFAOYSA-N 0.000 description 1
- 229910000337 indium(III) sulfate Inorganic materials 0.000 description 1
- PSCMQHVBLHHWTO-UHFFFAOYSA-K indium(iii) chloride Chemical compound Cl[In](Cl)Cl PSCMQHVBLHHWTO-UHFFFAOYSA-K 0.000 description 1
- XGCKLPDYTQRDTR-UHFFFAOYSA-H indium(iii) sulfate Chemical compound [In+3].[In+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O XGCKLPDYTQRDTR-UHFFFAOYSA-H 0.000 description 1
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 description 1
- JRSGPUNYCADJCW-UHFFFAOYSA-K iron(3+);trichlorate Chemical compound [Fe+3].[O-]Cl(=O)=O.[O-]Cl(=O)=O.[O-]Cl(=O)=O JRSGPUNYCADJCW-UHFFFAOYSA-K 0.000 description 1
- LHOWRPZTCLUDOI-UHFFFAOYSA-K iron(3+);triperchlorate Chemical compound [Fe+3].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O LHOWRPZTCLUDOI-UHFFFAOYSA-K 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
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 229940071125 manganese acetate Drugs 0.000 description 1
- 239000011565 manganese chloride Substances 0.000 description 1
- 235000002867 manganese chloride Nutrition 0.000 description 1
- 229940099607 manganese chloride Drugs 0.000 description 1
- 229940099596 manganese sulfate Drugs 0.000 description 1
- 239000011702 manganese sulphate Substances 0.000 description 1
- 235000007079 manganese sulphate Nutrition 0.000 description 1
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- QVRFMRZEAVHYMX-UHFFFAOYSA-L manganese(2+);diperchlorate Chemical compound [Mn+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O QVRFMRZEAVHYMX-UHFFFAOYSA-L 0.000 description 1
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- 229940078494 nickel acetate Drugs 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229940053662 nickel sulfate Drugs 0.000 description 1
- RZLUIDROFNIMHF-UHFFFAOYSA-L nickel(2+);dichlorate Chemical compound [Ni+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O RZLUIDROFNIMHF-UHFFFAOYSA-L 0.000 description 1
- ZLQBNKOPBDZKDP-UHFFFAOYSA-L nickel(2+);diperchlorate Chemical compound [Ni+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O ZLQBNKOPBDZKDP-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- KUJRRRAEVBRSIW-UHFFFAOYSA-N niobium(5+) pentanitrate Chemical compound [Nb+5].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O KUJRRRAEVBRSIW-UHFFFAOYSA-N 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- DCKVFVYPWDKYDN-UHFFFAOYSA-L oxygen(2-);titanium(4+);sulfate Chemical compound [O-2].[Ti+4].[O-]S([O-])(=O)=O DCKVFVYPWDKYDN-UHFFFAOYSA-L 0.000 description 1
- AOLPZAHRYHXPLR-UHFFFAOYSA-I pentafluoroniobium Chemical compound F[Nb](F)(F)(F)F AOLPZAHRYHXPLR-UHFFFAOYSA-I 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical class OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 229910000348 titanium sulfate Inorganic materials 0.000 description 1
- XROWMBWRMNHXMF-UHFFFAOYSA-J titanium tetrafluoride Chemical compound [F-].[F-].[F-].[F-].[Ti+4] XROWMBWRMNHXMF-UHFFFAOYSA-J 0.000 description 1
- SOCDLWOJPVKBHF-UHFFFAOYSA-J titanium(4+) tetraperchlorate Chemical compound [Ti+4].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O SOCDLWOJPVKBHF-UHFFFAOYSA-J 0.000 description 1
- 239000004246 zinc acetate Substances 0.000 description 1
- 229960000314 zinc acetate Drugs 0.000 description 1
- GTQFPPIXGLYKCZ-UHFFFAOYSA-L zinc chlorate Chemical compound [Zn+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O GTQFPPIXGLYKCZ-UHFFFAOYSA-L 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
- RXBXBWBHKPGHIB-UHFFFAOYSA-L zinc;diperchlorate Chemical compound [Zn+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O RXBXBWBHKPGHIB-UHFFFAOYSA-L 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
- G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
- G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
- G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
- G11B5/70642—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides
- G11B5/70678—Ferrites
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0036—Mixed oxides or hydroxides containing one alkaline earth metal, magnesium or lead
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0063—Mixed oxides or hydroxides containing zinc
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0072—Mixed oxides or hydroxides containing manganese
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/009—Compounds containing, besides iron, two or more other elements, with the exception of oxygen or hydrogen
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G51/00—Compounds of cobalt
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Description
本発明は、磁気記録用バリウムフエライト微結
晶粉末の製造方法に関し、詳しくは、六角板状性
にすぐれると共に、粒径が実質的に0.05〜0.2μm
の範囲にある磁気記録用バリウムフエライト微結
晶粉末の製造方法に関する。
バリウムフエライトは、一般に六角板状の結晶
性を有する磁性材料であつて、ハードフエライ
ト、ゴム磁石、垂直磁気記録等、種々の分野にお
いて用いられているが、目的、用途によつてバリ
ウムフエライトに要求される粒径や形状が異なる
一方、製造方法によつて、得られるバリウムフエ
ライトの粒径、粒径分布、六角板状性等が異な
り、例えば、垂直磁気記録用には六角板状性にす
ぐれると共に微細であるバリウムフエライト粉末
が要求される。
従来、六角板状バリウムフエライト粉末は、代
表的には、炭酸バリウムと酸化鉄を混合し、これ
に更に塩化バリウムのような所謂フラツクスを混
合し、このような乾式混合物を1100℃以上の高温
で焼成することによつて製造されている。しか
し、この方法によれば、得られるバリウムフエラ
イトには粒径が数μm程度に大きい粒子が含まれ
ており、粒径0.5μm以下で、且つ、均一な形状を
有する微結晶バリウムフエライト粉末を得ること
は困難である。
また、別の方法として、バリウムイオンと鉄
（）イオンとを水溶液中、常温常圧下でPH８以
上で反応させて沈殿を生ぜしめ、次にこの沈殿を
900℃又はそれ以上の温度で焼成してバリウムフ
エライト粉末を製造する方法が知られている。し
かし、この方法によれば、沈殿物の焼成過程にお
いて、一部粒子が相互に融着焼結するため、前記
の方法と同様に、粒径0.5μm以下の微結晶バリウ
ムフエライト粉末を得るのが困難である。
このような問題を解決するために、特開昭56−
160328号公報には、先ず、バリウムフエライトを
構成する割合にて各元素イオンを含有するPH12以
上のアルカリ性水溶液を高温に加熱する水熱反応
によつて、バリウムフエライトの前駆体沈殿物を
生成させ、これを水洗、乾燥した後、この前駆体
沈殿物を800℃以上の温度で焼成して、六角板状
バリウムフエライト微結晶粉末を製造する方法が
提案されている。この方法において、上記バリウ
ムフエライト前駆体沈殿物は、化学組成の点では
バリウムフエライトと同じであるが、結晶化が不
完全であるので、殆どの場合、実用には供し難
い。特に、磁性材料としては、磁気特性、例え
ば、保磁力や飽和磁化が著しく小さいので、実用
は困難である。
このため、この方法によれば、このような前駆
体を所定温度で焼成することにより、六角板状へ
の結晶化を進めるが、尚、焼成段階において前駆
体沈殿物粒子が相互に融着するのを避けられず、
かくして、得られるバリウムフエライト粉末は、
六角板状形からのくずれが大きい。従つて、この
ようなバリウムフエライト粉末を例えば磁気記録
材料として用いて磁気記録媒体を製作した場合、
その磁気記録特性が満足すべきものではなく、特
に、角形比が小さいために、出力感度が劣る問題
がある。尚、以下においては、バリウムフエライ
ト粉末の六角板状の形状が揃うことを六角板状性
が高いと称することがある。
本発明は、六角板状バリウムフエライト粉末の
製造における上記した問題を解決するためになさ
れたものであり、粒径が実質的に0.05〜0.2μmの
範囲にあつて、且つ、六角板状性が高いために、
角形比の大きい垂直磁気記録媒体を与える磁気記
録用六角板状バリウムフエライト微結晶粉末の製
造方法に提供することを目的とする。
本発明による磁気記録用バリウムフエライト微
結晶粉末の製造方法は、一般式
BaO・ｎ〔（Fe1-nMn）2O3〕
（但し、Ｍは、Co、Ti、Ni、Mn、Cu、Zn、In、
Ge及びNbよりなる群から選ばれる少なくとも１
種の置換元素を示し、ｍは０〜0.2、ｎは4.5〜6.0
を示す。）
で表わされるバリウムフエライトにおける成分元
素モル比を満足するようにバリウムイオン、鉄
（）イオン、及び必要に応じて置換元素Ｍイオ
ンを含有するPH12以上のアルカリ性水溶液を150
〜300℃に加熱して、バリウムフエライト前駆体
を沈殿させ、次いで、この前駆体を塩化バリウム
と共に700〜900℃の温度で焼成した後、上記塩化
バリウムを溶出させ、除去して、粒子径0.05〜
0.2μmの磁気記録用バリウムフエライト微結晶粉
末を得るものである。
本発明の方法においては、先ず、上記した所定
の化学組成を有するバリウムフエライトにおける
成分元素モル比を満足するように、バリウムイオ
ン、鉄（）イオン、及び必要に応じて置換元素
Ｍのイオンを含有するアルカリ性水溶液を150〜
300℃の範囲の温度にて加熱、即ち、水熱反応さ
せ、上記各元素イオンの共沈物をバリウムフエラ
イト粉末の前駆体として生成させる。
本発明の方法によれば、所定のイオンを含有す
る上記アルカリ性水溶液を調製するに際して、成
分元素モル比を上記のように所定の範囲とするこ
とが必要であり、ｍ及びｎが上記所定の範囲をは
ずれるときは、六角板状性の高いバリウムフエラ
イト微結晶粉末を得ることが困難である。
前記一般式において、Ｍは置換元素を意味し、
本発明においては、Co、Ti、Ni、Mn、Cu、
Zn、In、Ge及びNbよりなる群から選ばれる少な
くとも１種であり、得られるバリウムフエライト
の用途に応じて適宜に選ばれる。
上記アルカリ性水溶液は、通常、バリウムイオ
ン、鉄（）イオン、及び必要に応じて置換元素
イオンを含む水溶液をそれぞれ調製し、これらを
それぞれ所定濃度で各イオンを含むように混合し
た後、この混合水溶液を所定濃度のアルカリ水溶
液に混合することによつて調製される。但し、こ
の方法は一つの好ましい例であつて、本発明の方
法においては、上記アルカリ性水溶液の調製は、
この方法に限定されるものではない。
バリウムイオン、鉄（）イオン、及び置換元
素イオンを含む水溶液は、それぞれのイオンの水
溶性化合物を水に溶解して調製され、このような
水溶性化合物は各元素イオンに応じて適宜に選ば
れる。このような水溶性化合物として、例えば硝
酸バリウム、硝酸第二鉄、硝酸コバルト、硝酸チ
タン、硝酸ニツケル、硝酸マンガン、硝酸銅、硝
酸亜鉛、硝酸インジウム、硝酸ゲルマニウム及び
硝酸ニオブのような硝酸塩、過塩素酸バリウム、
過塩素酸第二鉄、過塩素酸第二コバルト、過塩素
酸チタン、過塩素酸ニツケル、過塩素酸マンガ
ン、過塩素酸第二銅、過塩素酸亜鉛、過塩素酸イ
ンジウムのような過塩素酸塩、塩素酸バリウム、
塩素酸第二鉄、塩素酸第二コバルト、塩素酸ニツ
ケル、塩素酸第二銅、塩素酸亜鉛のような塩素酸
塩、塩化バリウム、塩化第二鉄、塩化第二コバル
ト、四塩化チタン、塩化ニツケル、塩化第二銅、
塩化マンガン及び塩化インジウムのような塩化
物、フツ化第二鉄、フツ化第二コバルト、フツ化
チタン、フツ化第二銅、フツ化ゲルマニウム及び
フツ化ニオブのようなフツ化物、酢酸バリウム、
酢酸第二鉄、酢酸コバルト、酢酸ニツケル、酢酸
マンガン及び酢酸亜鉛のような酢酸塩、硫酸酸コ
バルト、硫酸チタン、硫酸ニツケル、硫酸マンガ
ン、硫酸亜鉛及び硫酸インジウムのような硫酸塩
を例示することができる。
本発明の方法においては、上記のようなバリウ
ムイオン、鉄（）イオン、及び必要に応じて置
換元素イオンを含むアルカリ性水溶液はそのPHが
12以上であることが必要である。アルカリ性水溶
液のPHが12よりも小さいときは、粒径が0.2μm以
下のバリウムフエライト微結晶粉末を得ることが
困難である。アルカリ性水溶液は特にPH13以上で
あることが好ましい。アルカリとしては強アルカ
リが好ましく用いられる。例えば、水酸化ナトリ
ウム、水酸化カリウム、水酸化リチウム等が用い
られる。
アルカリ性水溶液は密閉容器、例えばオートク
レーブ中で150〜300℃の範囲の温度に加熱され
る。即ち、水熱反応に付される。加熱時間は特に
制限されないが、通常、数十分乃至数時間であ
る。
本発明の方法においては、この水熱反応によつ
て前記一般式で表される化学組成を有するバリウ
ムフエライト粉末前駆体を得る。この前駆体は、
第１図に示すように、既にほぼ六角板状の結晶形
を有しているが、結晶化が不完全である。従つ
て、例えば、磁性材料として用いる場合には、磁
気特性、特に保磁力及び飽和磁化が著しく低い。
前記したように、この前駆体を水洗、乾燥した
後に焼成することにより、前駆体を結晶化させ
て、六角板状のバリウムフエライト微結晶粉末を
得ることができるが、本発明の方法によれば、こ
の前駆体を塩化バリウムと共に700〜900℃の温度
で焼成して、粒子間相互の融着焼結を防止しつ
つ、六角板状への結晶化を完全に行わせることが
でき、かくして、焼成後に焼成物を水洗し、水溶
性である上記塩化バリウムを溶出させ、除去する
ことにより、粒子径が0.2μm以下であるバリウム
フエライト微結晶粉末を得ることができる。ここ
に粒子径とは六角板状粒子の最大長軸、即ち、対
向する頂点間の距離のうち、最大の距離を意味す
る。
即ち、本発明の方法によれば、焼成に際して塩
化バリウムが前駆体粒子間に介在され、この塩化
バリウムが焼結防止剤としてと共に、細かいバリ
ウムフエライト粒子を六角板状に成長させる整粒
剤として作用するので、粒子が相互に分離され、
いわば稀釈されるので、粒子間の焼結が生じるこ
となく六角板状への結晶化が進行し、その結果、
第２図乃至第４図に示すように、粒子径が0.2μm
以下であつて、且つ、粒子形状が六角板状に揃つ
た、即ち、六角板状性の高いバリウムフエライト
微結晶粉末を得ることができるのである。
本発明の方法において、上記塩化バリウムは、
バリウムフエライト前駆体100重量部について50
重量部以上が用いられる。塩化バリウムの使用量
が少なすぎるときは、前駆体に対する稀釈効果が
十分でないので、前駆体の焼成時に粒子が融着焼
結する。他方、この塩化バリウムは、前駆体の焼
成後に焼成物を水洗することにより、焼成物から
溶出され、除去されるので、前駆体に対して大過
剰に用いてもよいが、しかし、特に大過剰に用い
ても、その溶出除去の操作に長時間を要すること
となるほか、特に利点もないので、本発明の方法
においては好ましくは100〜200重量部の範囲で用
いられる。
本発明の方法において、バリウムフエライト前
駆体を上記塩化バリウムの共存下に焼成するに
は、具体的には、例えば、前駆体を塩化バリウム
と共に湿式混練し、乾燥した後、必要に応じて造
粒し、或いは粉砕した後、これを電気炉中にて所
定温度で焼成すればよい。しかし、この方法に限
定されるものではない。
焼成温度は、700〜900℃の範囲である。700℃
よりも低い温度では前駆体の結晶化が不十分であ
つて、得られるバリウムフエライト粉末は、例え
ば、その磁気特性が尚劣り、特に、飽和磁化が低
い。他方、900℃を越える高温で焼成するときは、
塩化バリウムの共存下にあつても、尚粒子間の焼
結が部分的に生じる傾向があり、得られるバリウ
ムフエライト粉末の粒子径が0.2μmを越えて、磁
気記録材料として用いるとき、ノイズが大きくな
るので好ましくない。特に、本発明の方法によれ
ば、焼成温度は800〜900℃の範囲が好適である。
以上のように、本発明の方法によれば、所定の
元素イオンを含有するアルカリ性水溶液を水熱反
応に付し、得られたバリウムフエライト前駆体を
塩化バリウムと共に700〜900℃の温度で焼成する
ので、前駆体粒子は相互に融着焼結を起こすこと
なく、且つ、細粒は成長を促進されつつ、完全に
六角板状に結晶化される。従つて、焼成後に焼成
物より塩化バリウムを溶出させ、除去することに
より、粒子径が実質的に0.05〜0.2μmの範囲にあ
ると共に、従来に比較して、高度に六角板状に結
晶化されたバリウムフエライト微結晶粉末を得る
ことができる。特に、本発明の方法によつて得ら
れるバリウムフエライト粉末は、重要な磁気特性
である角形比において、従来のフエライトバリウ
ム粉末に比べて格段にすぐれている。
このように、本発明の方法により得られる磁気
記録用バリウムフエライト微結晶粉末は、粒子径
が小さく、六角板状性が高いうえに、角形比が大
きいので、垂直磁気記録用材料として特に好適に
用いることができる。
即ち、従来、磁気記録再生には磁気記録媒体、
例えば、磁気テープの面長手方向に磁気記録材料
を磁化し、その残留磁化を利用して記録再生する
方式が採用されており、従つて、磁気記録材料と
しての磁性粒子粉末には、長軸方向に磁化容易軸
を有する針状晶マグヘマイト粒子、針状晶マグネ
タイト粒子、これらに異種金属を含有させた磁性
酸化鉄粉末等が用いられている。しかし、この方
式によれば、反磁界による磁化の減少が大きいた
め、高密度記録には限界がある。
従つて、近年、垂直磁気記録方式の実用化が進
められているが、この垂直磁気記録方式とは、磁
気記録媒体の面に垂直な方向に磁気記録材料を磁
化して記録する方式であり、高密度化するほど減
磁作用が小さくなり、また、隣接する帯磁粒子間
に吸引力が作用する結果、粒子が相互に磁性を強
め合うので、前記した従来方式に比べて記録密度
が大幅に向上する。
従つて、このような垂直磁気記録方式に用いる
磁気記録材料は、磁気記録媒体面の垂直方向に磁
化容易軸を有することが必要であり、例えば、特
公昭58−47846号公報に記載されているように、
かかる特性を有する磁気記録材料として、近年、
六角板状のバリウムフエライト粉末が好適である
として注目されているのである。
ここに、典型的なバリウムフエライト、
BaO・6Fe2O3は、前記一般式においてｍが０で
ある場合であり、通常、3000〜60000eの保磁力を
有するが、この保磁力は磁気記録媒体には高すぎ
るので、鉄（）イオンの一部を前記置換元素Ｍ
で置換することにより、得られるバリウムフエラ
イト粉末の保磁力を約20000e以下に減少させるこ
とができる。置換元素としては、前記したよう
に、Co、Ti、Ni、Mn、Cu、Zn、In、Ge及び
Nbよりなる群から選ばれる少なくとも１種であ
るが、好ましくは、Co又はCoと他の元素との組
合せが選ばれる。
以下に実施例を挙げて本発明を説明する。
実施例１〜７及び比較例１
(1) バリウムフエライトの調製及びその性質濃度
３モル／の塩化第二鉄水溶液3467ml、1.0モ
ル／の塩化バリウム水溶液1100ml、1.0モ
ル／の塩化コバルト水溶液800ml及び1.0モ
ル／の四塩化チタン水溶液800mlを混合し、
この混合水溶液を濃度15モル／の水酸化ナト
リウム水溶液5093mlに15〜20℃の温度にて添加
し、Fe、Ba、Co及びTiの共沈物を含有するPH
14の水溶液を得た。
次に、この共沈物を含有する水溶液をオート
クレーブ中で250℃の温度にて４時間加熱して、
BaO・5.45〔Fe1.908Ti0.147Co0.147O3.3）
なる組成を有する前駆体沈殿物を得、この沈殿
物を洗滌水がPH８以下になるまで水洗した後、
乾燥した。この前駆体の電子顕微鏡写真
（60000倍、以下同じ。）を第１図に示す。
この乾燥した前駆体沈殿物と塩化バリウムと
をニーダーを用いて種々の割合にて水と共に湿
式混合し、粒径約３mmの球状物に造粒した後、
乾燥した。これを表に示す温度でそれぞれ３時
間電気炉中で焼成した後、この焼成物を粗粉砕
し、次に、サンドグラインダーを用いて湿式粉
砕し、この後、水洗して塩化バリウムを焼成物
から溶出除去し、濾過、乾燥して、バリウムフ
エライト微結晶粉末を得た。このようにして得
られたバリウムフエライトの特性を表に示す。
即ち、上記それぞれのバリウムフエライト粉
末について、振動試料型磁力計を用いて、飽和
磁化σs及び保持力iHcを測定した。また、粉末
の比表面積をBET法により測定した。更に、
粒子径を電子顕微鏡写真より測定した。
実施例３、４及び６によつて得られたバリウ
ムフエライトの電子顕微鏡写真をそれぞれ第２
図、第３図及び第４図に示す。第１図と比較し
て明らかなように、本発明によるバリウムフエ
ライト粉末は、いずれも形状の整つた六角板状
を呈し、その粒子径も実質的に0.05〜0.2μmの
範囲にある。
比較例１によるバリウムフエライト粉末は、
焼成を1000℃にて行なつて得られたものであつ
て、その電子顕微鏡写真を第５図に示すよう
に、粒子径が0.05〜0.3μmの範囲にわたつてい
る。
(2) 磁気テープの製作及びその磁気記録特性上で
得られたバリウムフエライト粉末78重量部につ
いて、バインダーとして塩化ビニル−酢酸ビニ
ル共重合体17重量部、可塑剤ジオクチルフタレ
ート４重量部、分散剤としてレシチン１重量
部、溶剤としてメチルエチルケトン120重量部
及びトルエン120重量部を加え、この混合物を
サンドミルにて混練し、磁性塗料を調製した。
この磁性塗料をポリエチレンテレフタレート
支持フイルム上に塗布し、4KGの磁界配向下
に乾燥して、支持フイルムに垂直の方向に異方
性を有する磁気記録テープを得た。
この磁気記録テープを振動試料型磁力計を用
いて減磁曲線を測定し、保持力iHc及び角形比
を測定した。結果を表に示す。
The present invention relates to a method for producing barium ferrite microcrystalline powder for magnetic recording, and more specifically, the present invention relates to a method for producing barium ferrite microcrystalline powder for magnetic recording.
The present invention relates to a method for producing barium ferrite microcrystalline powder for magnetic recording. Barium ferrite is generally a magnetic material with hexagonal plate-like crystallinity, and is used in various fields such as hard ferrite, rubber magnets, and perpendicular magnetic recording. While the grain size and shape of barium ferrite differ depending on the manufacturing method, the grain size, grain size distribution, hexagonal plate shape, etc. of the barium ferrite obtained also differ. A barium ferrite powder that is both transparent and fine is required. Conventionally, hexagonal plate-shaped barium ferrite powder is typically produced by mixing barium carbonate and iron oxide, and then adding a so-called flux such as barium chloride to this, and then drying this dry mixture at a high temperature of 1100°C or higher. It is manufactured by firing. However, according to this method, the obtained barium ferrite contains particles with a particle size as large as several μm, and it is difficult to obtain microcrystalline barium ferrite powder with a particle size of 0.5 μm or less and a uniform shape. That is difficult. Alternatively, barium ions and iron () ions are reacted in an aqueous solution at room temperature and pressure at pH 8 or above to form a precipitate, and then this precipitate is
A method of producing barium ferrite powder by firing at a temperature of 900° C. or higher is known. However, according to this method, some particles are fused and sintered with each other during the firing process of the precipitate, so it is difficult to obtain microcrystalline barium ferrite powder with a particle size of 0.5 μm or less in the same way as in the above method. Have difficulty. In order to solve such problems,
Publication No. 160328 discloses that first, a precursor precipitate of barium ferrite is generated by a hydrothermal reaction in which an alkaline aqueous solution with a pH of 12 or higher containing ions of each element in the proportions constituting barium ferrite is heated to a high temperature. A method has been proposed in which the precursor precipitate is washed with water, dried, and then calcined at a temperature of 800°C or higher to produce hexagonal plate-shaped barium ferrite microcrystalline powder. In this method, the barium ferrite precursor precipitate has the same chemical composition as barium ferrite, but it is incompletely crystallized, so it is difficult to put it to practical use in most cases. In particular, as a magnetic material, it is difficult to put it into practical use because its magnetic properties, such as coercive force and saturation magnetization, are extremely small. Therefore, according to this method, by firing such a precursor at a predetermined temperature, crystallization into a hexagonal plate shape is promoted, but the precursor precipitate particles are fused to each other during the firing stage. I can't avoid it,
In this way, the barium ferrite powder obtained is
There is a large deviation from the hexagonal plate shape. Therefore, when a magnetic recording medium is manufactured using such barium ferrite powder as a magnetic recording material, for example,
Its magnetic recording properties are unsatisfactory, and in particular, its squareness ratio is small, resulting in poor output sensitivity. Note that hereinafter, the fact that the hexagonal plate-like shape of the barium ferrite powder is uniform may be referred to as having high hexagonal plate-like property. The present invention was made to solve the above-mentioned problems in the production of hexagonal plate-shaped barium ferrite powder, and the particle size is substantially in the range of 0.05 to 0.2 μm and the hexagonal plate shape is Because of the high
The present invention aims to provide a method for manufacturing hexagonal plate-shaped barium ferrite microcrystalline powder for magnetic recording, which provides a perpendicular magnetic recording medium with a large squareness ratio. The method for producing barium ferrite microcrystalline powder for magnetic recording according to the present invention has the general formula BaO.n [(Fe 1-n M n ) 2 O 3 ] (where M is Co, Ti, Ni, Mn, Cu, Zn, In,
At least one selected from the group consisting of Ge and Nb
Indicates the substitution element of the species, m is 0 to 0.2, n is 4.5 to 6.0
shows. ) An alkaline aqueous solution with a pH of 12 or higher containing barium ions, iron () ions, and optionally substituent element M ions so as to satisfy the molar ratio of component elements in barium ferrite expressed by 150
After heating to ~300°C to precipitate the barium ferrite precursor, and then calcining this precursor with barium chloride at a temperature of 700-900°C, the barium chloride is eluted and removed, resulting in a particle size of 0.05 ~
0.2μm barium ferrite microcrystalline powder for magnetic recording is obtained. In the method of the present invention, first, barium ions, iron () ions, and, if necessary, ions of the substituent element M are added so as to satisfy the molar ratio of the component elements in barium ferrite having the above-mentioned predetermined chemical composition. 150~
Heating at a temperature in the range of 300° C., that is, a hydrothermal reaction, produces a coprecipitate of the above-mentioned elemental ions as a precursor of barium ferrite powder. According to the method of the present invention, when preparing the alkaline aqueous solution containing predetermined ions, it is necessary to set the component element molar ratio within the predetermined range as described above, and m and n are within the predetermined range. When it is removed, it is difficult to obtain barium ferrite microcrystalline powder with high hexagonal plate shape. In the general formula, M means a substitution element,
In the present invention, Co, Ti, Ni, Mn, Cu,
It is at least one member selected from the group consisting of Zn, In, Ge, and Nb, and is appropriately selected depending on the use of the obtained barium ferrite. The above alkaline aqueous solution is usually prepared by preparing aqueous solutions containing barium ions, iron () ions, and substituent element ions as necessary, mixing these to contain each ion at a predetermined concentration, and then creating a mixed aqueous solution. is prepared by mixing it with an alkaline aqueous solution of a predetermined concentration. However, this method is one preferred example, and in the method of the present invention, the preparation of the alkaline aqueous solution is as follows:
The method is not limited to this method. An aqueous solution containing barium ions, iron() ions, and substituent element ions is prepared by dissolving water-soluble compounds of each ion in water, and such water-soluble compounds are appropriately selected according to each element ion. . Such water-soluble compounds include, for example, nitrates such as barium nitrate, ferric nitrate, cobalt nitrate, titanium nitrate, nickel nitrate, manganese nitrate, copper nitrate, zinc nitrate, indium nitrate, germanium nitrate and niobium nitrate, perchlorine. barium acid,
Perchlorates such as ferric perchlorate, cobalt perchlorate, titanium perchlorate, nickel perchlorate, manganese perchlorate, cupric perchlorate, zinc perchlorate, and indium perchlorate. acid salt, barium chlorate,
Chlorates such as ferric chlorate, cobalt chlorate, nickel chlorate, cupric chlorate, zinc chlorate, barium chloride, ferric chloride, cobalt chloride, titanium tetrachloride, chloride Nickel, cupric chloride,
Chlorides such as manganese chloride and indium chloride, fluorides such as ferric fluoride, cobalt fluoride, titanium fluoride, cupric fluoride, germanium fluoride and niobium fluoride, barium acetate,
Examples include acetates such as ferric acetate, cobalt acetate, nickel acetate, manganese acetate and zinc acetate; sulfates such as cobalt sulfate, titanium sulfate, nickel sulfate, manganese sulfate, zinc sulfate and indium sulfate. can. In the method of the present invention, the pH of the alkaline aqueous solution containing barium ions, iron() ions, and optionally substituted element ions as described above is
Must be 12 or more. When the pH of the alkaline aqueous solution is lower than 12, it is difficult to obtain barium ferrite microcrystalline powder with a particle size of 0.2 μm or less. It is particularly preferable that the alkaline aqueous solution has a pH of 13 or higher. As the alkali, a strong alkali is preferably used. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. are used. The alkaline aqueous solution is heated in a closed container, such as an autoclave, to a temperature in the range of 150-300°C. That is, it is subjected to a hydrothermal reaction. The heating time is not particularly limited, but is usually several tens of minutes to several hours. In the method of the present invention, a barium ferrite powder precursor having a chemical composition represented by the above general formula is obtained through this hydrothermal reaction. This precursor is
As shown in FIG. 1, the crystal already has a substantially hexagonal plate shape, but the crystallization is incomplete. Therefore, for example, when used as a magnetic material, the magnetic properties, particularly the coercive force and saturation magnetization, are extremely low. As described above, by washing this precursor with water, drying it, and then firing it, the precursor can be crystallized and a hexagonal plate-shaped barium ferrite microcrystalline powder can be obtained, but according to the method of the present invention, By calcining this precursor with barium chloride at a temperature of 700 to 900°C, it is possible to completely crystallize it into a hexagonal plate shape while preventing mutual fusion and sintering of particles. After firing, the fired product is washed with water to elute and remove the water-soluble barium chloride, thereby obtaining barium ferrite microcrystalline powder having a particle size of 0.2 μm or less. The particle diameter herein means the maximum long axis of a hexagonal plate-shaped particle, that is, the maximum distance among the distances between opposing vertices. That is, according to the method of the present invention, barium chloride is interposed between the precursor particles during firing, and this barium chloride acts as an anti-sintering agent and as a sizing agent that causes fine barium ferrite particles to grow into a hexagonal plate shape. so that the particles are separated from each other,
Because it is diluted, so to speak, crystallization into hexagonal plates progresses without sintering between particles, and as a result,
As shown in Figures 2 to 4, the particle size is 0.2μm.
It is possible to obtain a barium ferrite microcrystalline powder having the following properties and having a uniform hexagonal plate shape, that is, a highly hexagonal plate shape. In the method of the present invention, the barium chloride is
50 for 100 parts by weight of barium ferrite precursor
Parts by weight or more are used. If the amount of barium chloride used is too small, the diluting effect on the precursor is insufficient, so that particles are fused and sintered when the precursor is fired. On the other hand, this barium chloride is eluted and removed from the fired product by washing the fired product with water after firing the precursor, so it may be used in large excess with respect to the precursor. Even if it is used, the elution and removal operation will take a long time and there is no particular advantage. Therefore, in the method of the present invention, it is preferably used in the range of 100 to 200 parts by weight. In the method of the present invention, in order to calcinate the barium ferrite precursor in the coexistence of barium chloride, for example, the precursor is wet-kneaded with barium chloride, dried, and then granulated if necessary. Alternatively, after pulverizing, this may be fired at a predetermined temperature in an electric furnace. However, the method is not limited to this method. The firing temperature ranges from 700 to 900°C. 700℃
At lower temperatures, the precursor is insufficiently crystallized and the resulting barium ferrite powder has, for example, poorer magnetic properties, particularly low saturation magnetization. On the other hand, when firing at high temperatures exceeding 900℃,
Even in the coexistence of barium chloride, sintering between particles tends to occur partially, and when the particle size of the obtained barium ferrite powder exceeds 0.2 μm and it is used as a magnetic recording material, noise becomes large. This is not desirable. In particular, according to the method of the present invention, the firing temperature is preferably in the range of 800 to 900°C. As described above, according to the method of the present invention, an alkaline aqueous solution containing a predetermined element ion is subjected to a hydrothermal reaction, and the obtained barium ferrite precursor is calcined together with barium chloride at a temperature of 700 to 900°C. Therefore, the precursor particles do not undergo mutual fusion and sintering, and the growth of the fine particles is promoted while being completely crystallized into a hexagonal plate shape. Therefore, by eluting and removing barium chloride from the fired product after firing, the particle size is substantially in the range of 0.05 to 0.2 μm, and compared to conventional methods, the barium chloride is highly crystallized into hexagonal plate shapes. Barium ferrite microcrystalline powder can be obtained. In particular, the barium ferrite powder obtained by the method of the present invention is significantly superior to conventional ferrite barium powder in squareness ratio, which is an important magnetic property. As described above, the barium ferrite microcrystalline powder for magnetic recording obtained by the method of the present invention has a small particle size, high hexagonal tabularity, and a high squareness ratio, so it is particularly suitable as a material for perpendicular magnetic recording. Can be used. That is, conventionally, for magnetic recording and reproduction, magnetic recording media,
For example, a method has been adopted in which magnetic recording material is magnetized in the longitudinal direction of the surface of the magnetic tape and recording and reproduction is performed using the residual magnetization. Acicular maghemite particles, acicular magnetite particles, and magnetic iron oxide powders containing different metals are used. However, according to this method, there is a limit to high-density recording because the magnetization decreases significantly due to the demagnetizing field. Therefore, in recent years, the practical application of perpendicular magnetic recording methods has been progressing. This perpendicular magnetic recording method is a method of recording by magnetizing a magnetic recording material in a direction perpendicular to the surface of a magnetic recording medium. The higher the density, the smaller the demagnetization effect, and as a result of the attraction force acting between adjacent magnetized particles, the particles strengthen each other's magnetism, resulting in a significant improvement in recording density compared to the conventional method described above. do. Therefore, the magnetic recording material used in such a perpendicular magnetic recording system must have an axis of easy magnetization in the direction perpendicular to the surface of the magnetic recording medium. like,
In recent years, magnetic recording materials with such properties have been developed.
Hexagonal plate-shaped barium ferrite powder is attracting attention as being suitable. Here, a typical barium ferrite,
BaO 6Fe 2 O 3 is the case where m is 0 in the above general formula, and usually has a coercive force of 3000 to 60000e, but this coercive force is too high for magnetic recording media, so iron () ions A part of the above-mentioned substituting element M
By substituting with , the coercive force of the obtained barium ferrite powder can be reduced to about 20,000e or less. As mentioned above, substitution elements include Co, Ti, Ni, Mn, Cu, Zn, In, Ge and
At least one element selected from the group consisting of Nb is selected, and preferably Co or a combination of Co and another element is selected. The present invention will be explained below with reference to Examples. Examples 1 to 7 and Comparative Example 1 (1) Preparation and properties of barium ferrite 3467 ml of a ferric chloride aqueous solution with a concentration of 3 mol/1.0 mol/1.0 mol/1.0 mol/of a barium chloride aqueous solution 1100 ml, 800 ml of a 1.0 mol/cobalt chloride aqueous solution Mix 800ml of titanium tetrachloride aqueous solution of mol/
This mixed aqueous solution was added to 5093 ml of sodium hydroxide aqueous solution with a concentration of 15 mol/at a temperature of 15 to 20°C, and the PH
An aqueous solution of 14 was obtained. Next, the aqueous solution containing this coprecipitate was heated in an autoclave at 250°C for 4 hours to obtain a precursor precipitate having a composition of BaO 5.45 [Fe 1.908 Ti 0.147 Co 0.147 O 3.3 ) , After washing this precipitate with water until the washing water becomes PH8 or less,
Dry. An electron micrograph (60,000 times, same applies hereinafter) of this precursor is shown in FIG. This dried precursor precipitate and barium chloride were wet-mixed with water in various proportions using a kneader and granulated into spherical particles with a particle size of about 3 mm.
Dry. After firing this in an electric furnace at the temperature shown in the table for 3 hours each, the fired product was coarsely ground, then wet-pulverized using a sand grinder, and then washed with water to remove barium chloride from the fired product. It was eluted and removed, filtered and dried to obtain barium ferrite microcrystal powder. The properties of the barium ferrite thus obtained are shown in the table. That is, the saturation magnetization σ s and coercive force iHc of each of the barium ferrite powders described above were measured using a vibrating sample magnetometer. Further, the specific surface area of the powder was measured by the BET method. Furthermore,
The particle size was measured from electron micrographs. Electron micrographs of barium ferrite obtained in Examples 3, 4, and 6 are shown in the second column.
3 and 4. As is clear from a comparison with FIG. 1, the barium ferrite powders according to the present invention all have a well-shaped hexagonal plate shape, and the particle size is substantially in the range of 0.05 to 0.2 μm. The barium ferrite powder according to Comparative Example 1 is
It was obtained by firing at 1000° C., and as shown in the electron micrograph of FIG. 5, the particle size ranged from 0.05 to 0.3 μm. (2) Regarding 78 parts by weight of barium ferrite powder obtained in the production of magnetic tape and its magnetic recording properties, 17 parts by weight of vinyl chloride-vinyl acetate copolymer as a binder, 4 parts by weight of dioctyl phthalate as a plasticizer, and 4 parts by weight of a dispersant. 1 part by weight of lecithin, 120 parts by weight of methyl ethyl ketone and 120 parts by weight of toluene as solvents were added, and the mixture was kneaded in a sand mill to prepare a magnetic paint. This magnetic paint was applied onto a polyethylene terephthalate support film and dried under an oriented magnetic field of 4 KG to obtain a magnetic recording tape having anisotropy in the direction perpendicular to the support film. The demagnetization curve of this magnetic recording tape was measured using a vibrating sample magnetometer, and the coercive force iHc and squareness ratio were measured. The results are shown in the table.
【表】
比較例 ２及び３
実施例において調製した前駆体沈殿物を水洗、
乾燥した後、これに塩化バリウムを添化すること
なく、電気炉中で800℃又は900℃の温度で３時間
加熱焼成して、バリウムフエライト粉末を得た。
この方法により得られるバリウムフエライトは、
比較例３について、その電子顕微鏡写真を第６図
に示すように、前駆体の焼成の過程で前駆体が相
互に焼結して粗大な粒子を生じて、その六角板状
の形状がくずれていることが明瞭に認められる。
また、このようにして得たバリウムフエライト
粉末の磁気特性、及びこれを用いて実施例と同様
にして製作した磁気記録テープの磁気特性を表に
示すが、特に、磁気記録テープにおいても、本発
明によるバリウムフエライトを用いた場合に比べ
て角形比が劣ることが明らかである。[Table] Comparative Examples 2 and 3 Precursor precipitates prepared in Examples were washed with water,
After drying, it was heated and fired in an electric furnace at a temperature of 800°C or 900°C for 3 hours without adding barium chloride to obtain barium ferrite powder.
The barium ferrite obtained by this method is
Regarding Comparative Example 3, as shown in the electron micrograph in Figure 6, the precursors sintered with each other during the firing process to produce coarse particles, and the hexagonal plate shape was distorted. It is clearly recognized that there are In addition, the magnetic properties of the barium ferrite powder thus obtained and the magnetic properties of the magnetic recording tape manufactured using the same in the same manner as in the examples are shown in the table. It is clear that the squareness ratio is inferior to that when barium ferrite is used.
第１図はバリウムフエライト前駆体の電子顕微
鏡写真（60000倍、以下、同じ。）、第２図乃至第
４図は本発明の方法により得られたバリウムフエ
ライト粉末の電子顕微鏡写真、第５図は比較例と
してのバリウムフエライト粉末の電子顕微鏡写
真、第６図は従来の方法により得られたバリウム
フエライト粉末の電子顕微鏡写真である。
Fig. 1 is an electron micrograph of a barium ferrite precursor (60,000x, the same applies hereinafter), Figs. 2 to 4 are electron micrographs of barium ferrite powder obtained by the method of the present invention, and Fig. 5 is an electron micrograph of a barium ferrite precursor. An electron micrograph of barium ferrite powder as a comparative example, and FIG. 6 is an electron micrograph of barium ferrite powder obtained by a conventional method.
Claims (1)
Ge及びNbよりなる群から選ばれる少なくとも１
種の置換元素を示し、ｍは０〜0.2、ｎは4.5〜6.0
を示す。） で表わされるバリウムフエライトにおける成分元
素モル比を満足するようにバリウムイオン、鉄
（）イオン、及び必要に応じて置換元素Ｍイオ
ンを含有するPH12以上のアルカリ性水溶液を150
〜300℃に加熱して、バリウムフエライト前駆体
を沈殿させ、次いで、この前駆体を塩化バリウム
と共に700〜900℃の温度で焼成した後、上記塩化
バリウムを溶出させて除去することを特徴とする
粒子径0.05〜0.2μmの磁気記録用バリウムフエラ
イト微結晶粉末の製造方法。 ２ バリウムフエライト前駆体100重量部に対し
て塩化バリウム50〜200重量部を存在させること
を特徴とする特許請求の範囲第１項記載の磁気記
録用バリウムフエライト微結晶粉末の製造方法。[Claims] 1 General formula BaO·n [(Fe 1-n M n ) 2 O 3 ] (where M is Co, Ti, Ni, Mn, Cu, Zn, In,
At least one selected from the group consisting of Ge and Nb
Indicates the substitution element of the species, m is 0 to 0.2, n is 4.5 to 6.0
shows. ) An alkaline aqueous solution with a pH of 12 or higher containing barium ions, iron () ions, and optionally substituent element M ions so as to satisfy the molar ratio of component elements in barium ferrite expressed by 150
It is characterized by heating to ~300°C to precipitate a barium ferrite precursor, then calcining this precursor together with barium chloride at a temperature of 700 to 900°C, and then eluting and removing the barium chloride. A method for producing barium ferrite microcrystalline powder for magnetic recording with a particle size of 0.05 to 0.2 μm. 2. The method for producing barium ferrite microcrystalline powder for magnetic recording according to claim 1, characterized in that 50 to 200 parts by weight of barium chloride is present per 100 parts by weight of the barium ferrite precursor.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59175402A JPS61168532A (en) | 1984-08-23 | 1984-08-23 | Production of fine crystal powder of barium ferrite |
| DE19853529756 DE3529756A1 (en) | 1984-08-23 | 1985-08-20 | Process for preparing a microcrystalline hexagonal barium ferrite powder |
| NL8502314A NL8502314A (en) | 1984-08-23 | 1985-08-22 | PROCESS FOR THE PREPARATION OF MICROCRYSTALLINE BARIUM FRYRITE POWDER. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59175402A JPS61168532A (en) | 1984-08-23 | 1984-08-23 | Production of fine crystal powder of barium ferrite |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61168532A JPS61168532A (en) | 1986-07-30 |
| JPH0261418B2 true JPH0261418B2 (en) | 1990-12-20 |
Family
ID=15995462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59175402A Granted JPS61168532A (en) | 1984-08-23 | 1984-08-23 | Production of fine crystal powder of barium ferrite |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS61168532A (en) |
| DE (1) | DE3529756A1 (en) |
| NL (1) | NL8502314A (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08702B2 (en) * | 1985-04-04 | 1996-01-10 | 石原産業株式会社 | Method for producing ferromagnetic fine powder for magnetic recording |
| JPH0674146B2 (en) * | 1985-09-03 | 1994-09-21 | 宇部興産株式会社 | Barium ferrite powder manufacturing method |
| JPS6260209A (en) * | 1985-09-10 | 1987-03-16 | Sony Corp | Manufacture of hexagonal system ferrite magnetic powder |
| DE3729693A1 (en) * | 1986-09-05 | 1988-05-05 | Sony Corp | Process for preparing fine barium ferrite particles |
| US4828916A (en) * | 1986-12-27 | 1989-05-09 | Toda Kogyo Corporation | Plate-like magnetoplumbite type ferrite particles for magnetic recording and magnetic recording media using the same |
| JPS63170220A (en) * | 1987-01-09 | 1988-07-14 | Ube Ind Ltd | Barium ferrite magnetic powder and its production |
| JPS63170221A (en) * | 1987-01-09 | 1988-07-14 | Ube Ind Ltd | Barium ferrite magnetic powder and its production |
| JPS63225533A (en) * | 1987-03-13 | 1988-09-20 | Ube Ind Ltd | Production of barium ferrite powder |
| EP0349287B1 (en) * | 1988-06-28 | 1995-12-20 | Toda Kogyo Corp. | Plate-like composite ferrite fine particles suitable for use in magnetic recording and process for producing the same |
| FR2639647B1 (en) * | 1988-10-18 | 1990-09-21 | Kodak Pathe | MAGNETIC RECORDING MEDIUM |
| FR2638000B1 (en) * | 1988-10-18 | 1990-12-14 | Kodak Pathe | LARGE CAPACITY MAGNETIC MEMORY CARD AND MANUFACTURING METHOD |
| JPH02267122A (en) * | 1989-04-07 | 1990-10-31 | Nippon Zeon Co Ltd | Magnetic powder for magnetic recording medium |
| EP0399665B1 (en) * | 1989-04-28 | 1995-02-08 | Ngk Insulators, Ltd. | Method of manufacturing ferrite crystals and method of producing ferrite powders preferably used therefor |
| JPH02296303A (en) * | 1989-05-11 | 1990-12-06 | Nippon Zeon Co Ltd | Magnetic powder for magnetic record medium |
| US5055322A (en) * | 1989-11-02 | 1991-10-08 | Nippon Zeon Co., Ltd. | Method of producing magnetic recording media |
| JP5390756B2 (en) * | 2007-08-02 | 2014-01-15 | 関東電化工業株式会社 | Method for producing flaky Ba ferrite fine particles |
| JP5754091B2 (en) * | 2010-06-30 | 2015-07-22 | 戸田工業株式会社 | Method for producing hexagonal ferrite particle powder and method for producing magnetic recording medium |
| CN104671764B (en) * | 2015-01-29 | 2017-03-29 | 浙江大学 | A kind of niobium doping barium ferrite wave-absorbing powder material and preparation method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56160328A (en) * | 1980-05-08 | 1981-12-10 | Toshiba Corp | Manufacture of ba-ferrite powder |
| JPS5841647A (en) * | 1981-08-25 | 1983-03-10 | ゲオルク・フイツシヤ−・アクチエンゲゼルシヤフト | Permanent mold |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5820890B2 (en) * | 1974-03-01 | 1983-04-26 | サカイカガクコウギヨウ カブシキガイシヤ | Manufacturing method of ferrite particles |
-
1984
- 1984-08-23 JP JP59175402A patent/JPS61168532A/en active Granted
-
1985
- 1985-08-20 DE DE19853529756 patent/DE3529756A1/en not_active Withdrawn
- 1985-08-22 NL NL8502314A patent/NL8502314A/en not_active Application Discontinuation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56160328A (en) * | 1980-05-08 | 1981-12-10 | Toshiba Corp | Manufacture of ba-ferrite powder |
| JPS5841647A (en) * | 1981-08-25 | 1983-03-10 | ゲオルク・フイツシヤ−・アクチエンゲゼルシヤフト | Permanent mold |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61168532A (en) | 1986-07-30 |
| NL8502314A (en) | 1986-03-17 |
| DE3529756A1 (en) | 1986-02-27 |
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