Process for manufacturing purple pigments

摘要

Prodn. of purple pigments based on a sinterable glass flux or other oxide or silicate carrier (mixt.) (I), coated with colloidal Au, comprises contacting fine (I) powder with Au cpd(s). (II) to give a wt. ratio of (I) to Au in (II) of (10-2000):1. (I) and (II) are mixed and/or milled dry or (I) is contacted with an aq. soln. or suspension of (II) in the absence of reducing agent. The mixt. is heated at a temp. above the decomposition temp. of (II) and below the sintering temp. of (I) until (II) is converted to colloidal Au. Also claimed is the pigment.