Thermostable iron oxide pigments

US4491619A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hans-Peter Biermann · Krefeld, DE
• Peter Kohler · Djursholm, SE
• Heinrich Heine · Krefeld, DE

Key dates

• Filing date: Mar 16, 1983
• Grant date: Jan 1, 1985
• Expiry date: Mar 16, 2003

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2991
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Iron oxide particles containing at least 5% by weight of iron (II) content calculated as FeO are stabilized against atmospheric oxidation by a coating of at least one compound containing boron and those particles are useful as coloring pigments and magnetic particles in magnetic recording media.