PURPOSE: To produce ferromagnetic iron powder of stable quality inexpensively by mixing and dispersing oxyhydroxide or oxide consisting essentially of iron and zinc borate, and heating the mixture in a nonreducing atmosphere according to need then reducing the same by heating.
CONSTITUTION: Needle goethite, etc. consisting of oxyhyroxide or oxide such as needle α-FeOOH and α-Fe2O3 are mixed and dispersed with zinc borate, if necessary, with a dispersant such as water by using a mixer such as an automatic mortar. The mixture is heated for about 30minW4hr at about 350°C in a non- reducing atmosphere of air or the like to convert the oxyhydroxide such as α- FeOOH to oxide such as α-Fe2O3 and to fit the same to zinc borate. Thereafter, the mixture is reduced at a relatively low temp. of about 200W450°C in gaseous H2 or a gaseous mixture contg. H2, whereby ferromagnetic iron powder is obtained. The amt. of the zinc borate to be added is adequately about 0.05/100W 5/100 by atomic weight ratio of boron and iron.
SUDOU KAZUFUYU
KOBAYASHI SADAO
FUKUDA NOBUHIRO
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