クロムスズピンク色顔料のチタニウム置換による発色変化  [in Japanese] Color Modification of Chromium-Tin Pink Pigment by Substitution of Ti for Sn  [in Japanese]

In the aim of the understanding of the coloration mechanism in Cr-doped inorganic pink pigments, the valences of Cr dopant in sphene-type (CaTiSiO_5-CaSnSiO_5), perovskite-type (CaTiO_3-CaSnO_3) and rutile-type (TiO_2-SnO_2) matrices were investigated by use of X-ray photoelectron spectroscopy (XPS). The valences of chromium were directly related to the color of the pigments. The valences were dependent on the Ti/Sn ratio in the mother crystals. Results of XPS showed that chromium ions doped in CaSnSiO_5 and CaSnO_3 matrices existed Cr^<4+> causing reddish purple color. With substitution of Ti for Sn in these matrices, the fraction of trivalent chromium increased and the color changed from reddish purple through purple red, red brown and finally to brown. A similar valence change of chromium was observed in the rutile-type pigments that changed lilac through brown to ocar colors. Purple red color was achieved in 2 mol% Cr-doped sphene- and perovskite-type pigments containing 20 mol% Ti.

In the aim of the understanding of the coloration mechanism in Cr-doped inorganic pink pigments, the valences of Cr dopant in sphene-type (CaTiSiO_5-CaSnSiO_5), perovskite-type (CaTiO_3-CaSnO_3) and rutile-type (TiO_2-SnO_2) matrices were investigated by use of X-ray photoelectron spectroscopy (XPS). The valences of chromium were directly related to the color of the pigments. The valences were dependent on the Ti/Sn ratio in the mother crystals. Results of XPS showed that chromium ions doped in CaSnSiO_5 and CaSnO_3 matrices existed Cr^<4+> causing reddish purple color. With substitution of Ti for Sn in these matrices, the fraction of trivalent chromium increased and the color changed from reddish purple through purple red, red brown and finally to brown. A similar valence change of chromium was observed in the rutile-type pigments that changed lilac through brown to ocar colors. Purple red color was achieved in 2 mol% Cr-doped sphene- and perovskite-type pigments containing 20 mol% Ti.