| 摘要 |
PURPOSE:To produce the title spherical fine particle without anisotropy, allowing random and perpendicular orientation, having large electric conductivity and magnetization, by bringing specified iron oxide fine particle into contact with reducing (carbonizing) agent. CONSTITUTION:The iron oxide fine particle coated the surface with 0.01-5wt.% at least one kind of metal compd. selected among Ni compd. (e.g. nickel acetate), Cu compd. (e.g. copper acetate) and Mn compd. (e.g. MnSO4), having 1-3 mean axis ratio and <=0.05-1mum mean particle size (major axis), as occasion demands, is brought into contact with the reducing agent contg. no carbon (e.g. H2) at the flow rate of 1-1,000ml STP/min per 1g iron fine particle at 200-700 deg.C under 1-2atm. pressure for 0.5-6hr and thereafter, is brought into contact with the reducing agent contg. carbon (e.g. CO) or the mixture of this reducing agent and the reducing agent contg. no carbon in the vol. ratio of 1:(0.05-5), at the flow rate of 1-1,000ml STP/min per 1g iron fine particle at 250-400 deg.C under 1-2atm. pressure for 0.5-6hr. |
