Colouring factories are continuously trying to synthesize structures suitable as ceramic pigments using cheap and non toxic raw materials. This investigation is aimed at developing a new structure suitable as ceramic pigment. In particular, ZrTiO4, the only binary phase in the system ZrO2-TiO2 existing in two forms of different structural order-disorder, was doped with different metal transition ions and counterions. Eighteen compositions were prepared through ceramic method with stoichiometry: ZrTi1-xAxO4, where A = Co, Cr, Fe, Mn, Ni, V (x=0.05) and ZrTi1-x-yAxByO4, where A= Co, Cr, Fe, Mn, Ni, V and B= Sb, W (x=y=0.05). Samples were characterised by coupling spectroscopic data, obtained through UV-Vis-NIR analysis, with structural ones, obtained through Rietveld refinement of XRPD. Furthermore, in order to test their technological suitability, these ceramic pigments were tested in frits, glazes and porcelain stoneware bodies, and fired products were colourimetrically characterized. The structural refinements were successfully carried out with the srilankite-type model, resulting in a disordered distribution of Zr and Ti. The disordered structure, reported as stable at high temperature (i.e. above 1200°C), can persist as metastable at low temperature due to the rapid cooling or the presence of stabilizing agents. It is likely that the metal transition ions doping might have favoured the formation of ZrTiO4 low order form. Besides, the splitting of the crystal field peaks, due to the presence of metal transition ions, can be interpreted as caused by a partial cation ordering. This splitting, together with a weak absorption band (onset at 23000 cm-1) caused by Ti4+-O2- charge transfer, determined the low colour purity of samples: dark green (Co, Ni), orange (Cr, V) and brown (Mn). Concerning ceramic behaviour, pigments are stable in low firing frits, while in high temperature applications, such glazes and porcelain stoneware bodies, ZrTiO4 doped with Co, V and Mn tends to be dissolved.
Crystal Structure, Colour and Technological Properties of Srilankite (ZrTiO2) Ceramic Pigments
Dondi M;
2005
Abstract
Colouring factories are continuously trying to synthesize structures suitable as ceramic pigments using cheap and non toxic raw materials. This investigation is aimed at developing a new structure suitable as ceramic pigment. In particular, ZrTiO4, the only binary phase in the system ZrO2-TiO2 existing in two forms of different structural order-disorder, was doped with different metal transition ions and counterions. Eighteen compositions were prepared through ceramic method with stoichiometry: ZrTi1-xAxO4, where A = Co, Cr, Fe, Mn, Ni, V (x=0.05) and ZrTi1-x-yAxByO4, where A= Co, Cr, Fe, Mn, Ni, V and B= Sb, W (x=y=0.05). Samples were characterised by coupling spectroscopic data, obtained through UV-Vis-NIR analysis, with structural ones, obtained through Rietveld refinement of XRPD. Furthermore, in order to test their technological suitability, these ceramic pigments were tested in frits, glazes and porcelain stoneware bodies, and fired products were colourimetrically characterized. The structural refinements were successfully carried out with the srilankite-type model, resulting in a disordered distribution of Zr and Ti. The disordered structure, reported as stable at high temperature (i.e. above 1200°C), can persist as metastable at low temperature due to the rapid cooling or the presence of stabilizing agents. It is likely that the metal transition ions doping might have favoured the formation of ZrTiO4 low order form. Besides, the splitting of the crystal field peaks, due to the presence of metal transition ions, can be interpreted as caused by a partial cation ordering. This splitting, together with a weak absorption band (onset at 23000 cm-1) caused by Ti4+-O2- charge transfer, determined the low colour purity of samples: dark green (Co, Ni), orange (Cr, V) and brown (Mn). Concerning ceramic behaviour, pigments are stable in low firing frits, while in high temperature applications, such glazes and porcelain stoneware bodies, ZrTiO4 doped with Co, V and Mn tends to be dissolved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
