MAGNETIC RECORDING MEDIUM

• Main Authors: MIURA TOSHIHIKO, HONDA KUNIHIKO, ARAKI HIROAKI
• Format: Patent
• Language: English
• Published: 27.04.1988
• 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 improve weatherability by using iron oxide-contg. iron nitride powder contg. specific iron oxide at a specific ratio with Fe4N and having 150-250Angstrom crystallite size as ferromagnetic powder. CONSTITUTION:The iron oxide-contg. iron nitride powder contg. the iron oxide (FeOx, 4/3<=x<=3/2) at 0.5-10% of Fe4N (integrated intensity ratio of X-ray diffractions) and having 150-250Angstrom crystallite size is used for the ferromagnetic powder of a magnetic recording medium formed by providing a magnetic layer contg. the ferromagnetic powder and binder on a nonmagnetic base. The iron oxide-contg. iron nitride powder to be used as the ferromagnetic powder is obtd. by first nitriding metal iron powder at about 300-500 deg.C in gaseous NH3+H2 flow to form iron oxide essentially consisting of gamma'-Fe4N, and subjecting such iron nitride to surface slow oxidation for several tens - several hours at about room temp. 50 deg.C in the atm. or oxygen atmosphere. Such iron metal powder which yields the iron oxide-contg. iron nitride powder having 150-250Angstrom , more preferably 150-200Angstrom crystallite size (X-ray crystal size) is thereafter obtd.