Anticorrosive magnetic nanocolloids protected by precious metals

US6491842B1 · kind B1 · utility

Assignees

• Studiengesellschaft Kohle gGmbH · DE
• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Helmut Bonnemann · Neheim, DE
• Werner Brijoux · Oberhausen, DE
• Rainer Brinkmann · Wetter (Ruhr), DE
• Michael Wagener · Wiesloch, DE

Key dates

• Filing date: Aug 11, 2000
• Grant date: Dec 10, 2002
• Expiry date: Aug 11, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01F1/442
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The invention relates to new single- or multi-metallic magnetic colloid particles (for example, Fe, Co, Ni, Fe/Co) having a size of up to 20 nm, the surface of which is protected against corrosion by precious metals, such as Pd, Ag, Pt or Au. The invention also relates to a method for producing such materials. In isolated form or in solution said materials are used among other things as sealing media against dust and gas in magnetic fluid seals (liquid O ring), for lubricating and mounting rotating shafts (magnetic levitation bearing), for the magnetooptic storage of information as well as for the magnetic marking of cells and their separation in biological samples or for the local administration of medicines.