Toda Kogyo Corporation

Atsushi Takedoi

Tosiharu Harada

Masaru Isoai

Mamoru Tanihara

Kazuhiro Fujita

Hideaki Sadamura

Kohji Mori

Hirofumi Kawasaki

Hiroshi Sumita

Yosiro Okuda

Hiroyuki Kondo

Yoshitaka Yoshinaga

Disclosed herein are magnetic iron oxide particles which have a spindle shape and a substantially uniform particle size and shape, and are substantially free of dendrites and have a large axial ratio (major axial diameter/minor axial diameter) and an excellent print-through characteristic, and a method of producing the same.

Magnetic iron oxide particles and method of producing the same

Magnetic iron oxide particles and method of producing same

Disclosed herein are poreless, non-sintered plate-like magnetite particles having an average particle diameter of more than 0.5 .mu.m and not more than 2.0 .mu.m, and a BET specific surface area of not more than 6.0 m.sup.2 /g, and poreless, non-sintered plate-like maghemite particles having an average particle diameter of more than 0.5 .mu.m and not more than 2.0 .mu.m, and a BET specific surface area of not more than 6.0 m.sup.2 /g.

Plate-like magnetite particles, plate-like maghemite particles and

Disclosed herein are magnetic iron oxide particles comprising spindle-like magnetite or maghemite particles having an aspect ratio(major:minor) of less than 4:1 and containing 0.1 to 20 atomic % of Si to Fe, and a process for producing the same.

Spindle-like magnetic iron oxide particles and process for producing the

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Hiroshima, Japan

Atsushi Takedoi