MAGNETIC METALLIC POWDER AND MAGNETIC RECORDING MEDIUM FORMED BY USING SAID POWDER

• Main Authors: SUEYOSHI TOSHINOBU, ASADA SEIICHI
• Format: Patent
• Language: English
• Published: 17.03.1988
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PHYSICS; POLISHES; USE OF MATERIALS THEREFOR; WOODSTAINS

PURPOSE:To prevent the diffusion of the metal, alloy layers, etc., on a surface into particles and to obtain magnetic powder and recording medium having good corrosion resistance by providing a diffusion preventive layer between the nucleus part and surface layer of magnetic metallic powder. CONSTITUTION:The diffusion preventive layer contg. elements having <=-0.7V oxidation-reduction potential and >=1,000 deg.C m.p. is provided between the nuclear part of the magnetic metallic powder and the layer of Ni, Co, etc., on the surface. The internal diffusion of Ni, Co, etc., is thereby suppressed and the magnetic metallic powder having high satn. magnetization and excellent corrosion resistance is obtd. The quantity of the metal elements to form the metal and alloy layers near the surface is specified to MF/Mc=0.5-50wt% when the metal quantity in the nuclear part is designated as Mc and the metal quantity of the layer essentially consisting of Co and Ni as MF. The metal quantity of the diffusion preventive layer is specified to Md/Mc=0.01-10wt% when the metal quantity of said layer is designated as Md and the metal quantity of the nuclear part as Mc.