| 摘要 |
PURPOSE:To obtain titled powder having a uniform grain size and large satd. magnetization by incorporating a specific amt. of water soluble silicate into the reaction soln. of an aq. ferrous salt and alkali carbonate and subjecting the goethite particles formed by oxidation to reduction under heating. CONSTITUTION:An aq. ferrous salt soln. (FeSO4, etc.) and alkali carbonate (K2CO3, etc.) are brought into reaction with each other at about 40-80 deg.C and about 7-11pH to form an aq. soln. contg. FeCO3. Water soluble silicate (silicate of Na, etc.) is added to the aq. soln. so as to be incorporated therein at 0.1- 10atom% in terms of Si by the atom% of Fe. A gas contg. oxygen is passed through such soln. to oxidize the soln., thereby forming the goethite particles having a spindle shape. The particles are dehydrated by heating and are subjected to reduction under heating in a reducing gas. The magnetic metallic particle powder which consists essentially of the iron having the spindle shape, has <=3:1 long axis: short axis, contains 0.1-10atom% Si by the atom% of Fe and has 500-1,000Oe coercive force is thus obtd. |
