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Chromium(IV) Stabilisation in New Ceramic Matrices by Coprecipitation Method: Application as Ceramic Pigments
Author(s) -
Monrós G.,
Pinto H.,
Badenes J.,
Llusar M.,
Tena M. A.
Publication year - 2005
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200570029
Subject(s) - coprecipitation , ceramic , chromium , materials science , chromate conversion coating , ceramic glaze , glaze , metallurgy , mineralogy , nuclear chemistry , inorganic chemistry , chemistry
In this paper the stabilization of Cr 4+ in new ceramic matrices as willemite Zn 2 SiO 4 and galium‐gadolinium garnet GGG (Gd 3 Ga 5 O 12 ) is studied and compared with the chromium‐sphene ceramic pigment using the traditional solid reaction and an unconventional coprecipitation method.The chromate amount etched from the powders using Cr III and Cr VI precursors on ceramic and coprecipitation routes are analysed in order to evaluate the environmental impact on the waste water. Cr‐willemite and codoped Ca, Cr‐GGG produces solid solutions of Cr 4+ ion occupying tetrahedral and dodecahedral sites, respectively, while Cr 4+ into sphene lattice occupies octahedral sites. Cr‐willemite are stable when used as ceramic pigment in habitual tile glazes but Cr‐GGG unstabilses and produces green colour associated to Cr 3+ solved in the glaze. Coprecipitate powders are more reactive than ceramic powders but in Cr‐GGG stabilizes the metastable Ca 3 Cr 2 O 8 oxide. Chromate amount in washing hot water are not dependent of the chromium precursor but depends of the allowed reactivity level and the reaction media.