Brown to gray inclusion pigments and method of their production

US5043016A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Dietrich Speer · Hanau, DE
• Akos Kiss · Alzenau, DE
• Peter Kleinschmit · Hanau, DE

Key dates

• Filing date: Dec 27, 1990
• Grant date: Aug 27, 1991
• Expiry date: Dec 27, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2002/52
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to new brown to gray inclusion pigments, based on zirconium silicate as casing substance, which are characterized in that they contain mixed crystals of the type (Fe.sub.1-x Mn.sub.x).sub.2 O.sub.3, in which x stands for a number in the range from 0.05 to 0.60, as colored compounds. The production takes place by means of annealing a mixture of SiO.sub.2 and ZrO.sub.2, or of precursors, in the presence of iron compounds and manganese compounds, in an Fe/Mn atomic ratio of 90:10 to 20:80, and mineralizers at 750.degree. to 1200.degree. C. The brown pigments are formed especially at temperatures of 850.degree. to 1000.degree. C. and if x is between 0.05 and 0.20. The gray pigments are formed especially at 1050.degree. to 1200.degree. C. and if x is 0.30 to 0.60.