Process for preparing agglomerate-free nanoscalar iron oxide particles with a hydrolysis resistant coating

US6183658A · kind A · utility

Assignee

• INSTITUT FUR NEUE MATERIALIEN gem. GmbH. · DE

Inventors

• Christoph Lesniak · Kempten (Allgäu), DE
• Thomas Schiestel · Riegelsberg, DE
• Rudiger Nass · Zellingen, DE
• Helmut Schmidt · Riegelsberg, DE

Key dates

• Filing date: Oct 9, 1998
• Grant date: Feb 6, 2001
• Expiry date: Oct 9, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2995
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing an agglomerate-free suspension of nanosize iron-containing oxide particles coated in a stable manner comprises preparing an aqueous suspension of nanosize iron-containing oxide particles which are partially or completely in the form of agglomerates; adding a trialkoxysilane and a water-miscible polar organic solvent which has a boiling point at least 10.degree. C. higher than the boiling point of water; treating the resulting suspension with ultrasound until at least 70% of the particles present are in the range of .+-.20% of the average particle diameter; removing the water by distillation under the action of ultrasound; and separating the non-disintegrated agglomerates.