In situ use of gelatin in the preparation of uniform ferrite particles
AssigneeCoulter Corporation
InventorsOlavi Siiman, Alexander Burshteyn
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Abstract
A method is described for the preparation of uniform colloidal particles of ferrites, containing manganese (II), zinc(II), barium(II), iron(II), cobalt(II), or nickel(II), or a mixture of manganese(II) and zinc(II), at a relatively low temperature in the presence of a gelatin solution which acts as a support vehicle for the nucleation and growth of colloidal particles of metal oxide and for dispersion as separate single particles.
Claims13
A method of making colloidal ferrite particles of uniform size and shape comprising:
- A. mixing a first solution of potassium nitrate and potassium hydroxide or sodium nitrate and sodium hydroxide, respectively, which has been nitrogen gas purged and a
- B. second solution of a ferrous salt, divalent metal salt and a gelatin solution which second solution has been nitrogen purged;
- C. sweeping the gelatinous metal hydroxide mixture of the two solutions with nitrogen gas and ripening same to form a ferrite hydrosol at a predetermined low temperature for a selected period of time;
- D. washing the hydrosol with said gelatin solution by magnetic separation and redispersion,
- whereby to form separate single metal ferrite particles coated with gelatin.
Colloidal particles which are monodispersed having a ferrite structure and a mean particle diameter of approximately 0.1 to 1.0 microns, said particles including a divalent metal ion selected from the group consisting of manganese(II), zinc(II), mixed Mn(II)-Zn(II), iron(II), barium(II.), cobalt(II) and nickel(II) and characterized as being well-defined and of uniform size and shape.
Dependencies are inferred from the claim text.