Manufacture of ferromagnetic metal particles consisting essentially of iron

US4155748A · kind A · utility

Assignee

• BASF SE

Inventors

• Werner Steck · Ludwigshafen, DE
• Hans H. Schneehage · Bad Dürkheim, DE
• Christof Jaeckh · Heidelberg, DE
• Werner Huebner · Bischofswerda, DE
• Manfred Ohlinger · Bischofswerda, DE
• Werner Loeser · Ludwigshafen, DE

Key dates

• Filing date: Sep 29, 1977
• Grant date: May 22, 1979
• Expiry date: Sep 29, 1997

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S428/90
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method of preparing acicular ferromagnetic metal particles consisting essentially of iron and suitable for magnetic recording, said particles being modified at the surface with 0.02 to 0.2% by weight of carbon and with 0.5 to 1.9% by weight of phosphorus as phosphate, by reducing a finely divided acicular iron compound, wherein there are deposited on said iron compound, prior to reduction, (a) a hydrolysis-resistant substance selected from the group consisting of oxyacids of phosphorus, their esters and inorganic salts, and (b) a compound selected from the group consisting of aliphatic monobasic, dibasic and tribasic carboxylic acids of from 1 to 6 carbon atoms.