In situ use of gelatin or an aminodextran 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), at a relatively low temperature in the presence of an aminodextran 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.
Claims9
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 ferrous salt, divalent metal salt and an aminodextran solution which second solution has been nitrogen purged;
- C. sweeping the aminodextran- 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 aminodextran solution by magnetic separation and redispersion,
- whereby to form separate single metal ferrite particles coated with an aminodextran.
The method of claim l in which the metal ion of said divalent metal salt is the Fe.sup.2+ ion.
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 the divalent metal ion manganese(II)) and characterized as being well-defined and of uniform size and shape.
Dependencies are inferred from the claim text.