PURPOSE: To obtain metal magnetic powder superior in magnetic characteristics and corrosion resistance by a method wherein the surface of powder particles is coated with the coprecipitated sediment of ferrous hydroxide and nickel hydroxide and then coated with a silicon compound, and it is subjected to heat treatment and then reduced under heating.
CONSTITUTION: A mixture of a nickel salt solution and an iron salt solution is gradually added into an alkaline suspension of powder mainly consisted of iron oxyhydroxide or iron oxide. As a result, the surface of powder particles is coated with the coprecipated sediment of ferrous hydroxide and nickel hydroxide. Next, a silicate solution is added thereto to neutralize the solution, so that the surface of powder particles is further coated with a silicon compound. These powder particles are heat-treated at temperature not lower than 500°C and then reduced under heating. Consequently, it becomes possible to restrain sintering between the particles and collapse thereof during the reducing under heating as well as to improve the coersive force and corrosion resistance.
| JPS648508 | MAGNETIC RECORDING MEDIUM |
| JP2562306 | [Title of Invention] Magnetic recording medium |
HIRAI SHIGEO
TASHIMO KATSUNORI
HAYASHI AKIHIRO
AMAMIYA MASAHIRO
