EP 0024694 B1 19830928 - PROCESS FOR PREPARING FERROMAGNETIC ACICULAR IRON PARTICLES, AND THEIR USE
Title (en)
PROCESS FOR PREPARING FERROMAGNETIC ACICULAR IRON PARTICLES, AND THEIR USE
Publication
Application
Priority
DE 2935358 A 19790901
Abstract (en)
[origin: US4344791A] A process for the manufacture of acicular ferromagnetic iron particles by heating a goethite, provided with a shape-stabilizing surface coating, at 250 DEG -450 DEG C. in an atmosphere containing water vapor at a partial pressure of not less than 30 mbar, to give alpha-iron(III) oxide, and reducing this material with hydrogen at 275 DEG -425 DEG C., and the use of the iron particles thus obtained as magnetic material in the production of magnetic recording media.
IPC 1-7
IPC 8 full level
B22F 9/22 (2006.01); C09D 5/23 (2006.01); C09D 7/12 (2006.01); G11B 5/70 (2006.01); G11B 5/706 (2006.01); H01F 1/06 (2006.01)
CPC (source: EP US)
B22F 9/22 (2013.01 - EP US); H01F 1/061 (2013.01 - EP US); H01F 1/065 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB NL
DOCDB simple family (publication)
EP 0024694 A2 19810311; EP 0024694 A3 19810826; EP 0024694 B1 19830928; DE 2935358 A1 19810326; DE 3065058 D1 19831103; JP S5638405 A 19810413; US 4344791 A 19820817
DOCDB simple family (application)
EP 80104979 A 19800821; DE 2935358 A 19790901; DE 3065058 T 19800821; JP 11854280 A 19800829; US 17426780 A 19800731