Preparation through Aerosols of Cr‐Doped Y ₂ Sn ₂ O ₇ (Pyrochlore) Red‐Shade Pigments and Determination of the Cr Oxidation State

Abstract

A method for the preparation of Cr‐doped Y 2 Sn 2 O 7 powders based on the pyrolysis of aerosols generated from aqueous salt solutions of the corresponding metal cations is reported. These powders yielded Cr‐doped pyrochlore red‐shade pigments on calcination in the absence of fluxes at lower temperature (900°–1100°C) than that involved in the traditional ceramic method (1400°C). This process resulted in pigment particles with spherical shape and broad size distribution (<10 μm) not requiring milling. The oxidation state of the Cr ions dissolved in the pyrochlore lattice has also been analyzed by using XPS and ESR spectroscopies and ac magnetic susceptibility measurements finding that the color observed for this material is due to Cr(IV) ions, most probably occupying the distorted octahedral position of Sn(IV).