固相反応によるコバルト含有γ-Fe2O3の合成

概要

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Co-containing γ-Fe2O3 is not prepared by solid state reaction of γ-Fe2O3 and CoO at high temperature but is prepared by wet method, because γ-Fe2O3 transforms into α-Fe2O3 above 400-500°C. However, γ-Fe2O3 is stabilized by the addition of potassium. To be reported here is a finding that the solid state reaction of acicular γ-Fe2O3 and Co(NO3)2⋅6H2O can be accomplished by the addition of K2CO3. When a mixture of γ-Fe2O3:Co(NO3)2⋅6H2O:K2CO3=5:1:0.2(molar ratio)was heated at 500-600°C, the coercivity of the product was above 1000 Oe. In addition, the magnetic property was also improved in the squareness ratio compared with the original γ-Fe2O3. The particle morphology of the obtained Co-containing γ-Fe2O3 was maintained acicular even after the heat treatment.
社団法人粉体粉末冶金協会の論文