Bayer Aktiengesellschaft

Peter Kohler

Heinrich Heine

Peter Ringe

Franz Hund

Horst Brunn

Johannes Niggemann

Hans-Peter Biermann

Yellow to orange-red bismuth oxide-chromium oxide mixed phase pigments having a specific surface from about 1 to 10 m.sup.2 /g and the composition Bi.sub.2-x Cr.sub.x O.sub.3 wherein x is from about 0.05 to 0.5 are produced by mixing the appropriate quantities of finely disperse bismuth-(III)-- and chromium-III-- or chromium-(VI)-compounds, calcining the mixture in air at a temperature from about 500.degree. to 800.degree. C. and subsequently grinding. The products are suitable for pigmenting lacquers, plastics and dispersion dyes.

Mixed phases having the composition Bi.sub.2-x Cr.sub.x O.sub.3

A depot fertilizer composition comprising an inorganic matrix and another inorganic and/or organic component of the formula

Inorganic depot fertilizers

A bismuth oxide/chromium oxide mixed phase pigment having the composition Bi.sub.2-x Cr.sub.x O.sub.3 wherein 0.05.times.0.5 and a specification surface of about 1.0 to 10 m.sup.2 /g is produced by mixing metallic bismuth intensively with a chromium (III) and/or chromium (VI) compound, calcining the homogeneous mixture in an oxidizing atmosphere at a temperature of about 500.degree. to 800.degree. C., and crushing the product to pigment size.

Production of bismuth oxide/chromium oxide mixed phase pigments

Yellow to orange-red bismuth oxide-chromium oxide mixed phase pigments having a specific surface from about 1 to 10 m.sup.2 /g and the composition Bi.sub.2-x Cr.sub.x O.sub.3 wherein x is from about 0.05 to 0.5 are produced by mixing the appropriate quantities of finely disperse bismuth-(III)- and chromium-(III)- or chromium-(VI)-compounds, calcining the mixture in air at a temperature from about 500.degree. to 800.degree. C. and subsequently grinding. The products are suitable for pigmenting lacquers, plastics and dispersion dyes.

Mixed phases having the composition Bi.sub.2-x Cr.sub.x O.sub.3 and a

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.

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Krefeld, Germany

Peter Kohler