Synthesis of new red coloured ceramic pigments by Pechini method

Various garnet solid solutions within the structure of the yttrium aluminiu m garnet, Y3Al5O12 (YAG) were sinthesized via Pechini and the possibility f or the modification of the crystal field intensity acting on the chromophor e Cr(III) ion by means of substitution with divalent (Mn(II) and Mg(II)) an d tetravalent (Ce(IV), Zr(IV) and Sn(IV)) cations was studied. The results obtained indicate that the crystal field can not be intensified through the introduction of divalent ions since they stabilize the Gr(IV) ion which pr obably expands the structure by inducing distortions in it. The introductio n of tetravalent ions makes possible the intensification of the crystal fie ld acting on the chromium and the change of the typical green colour of Cr( III) in a week field to red which is typical for the same in strong field. However, the structural studies carried our by X-ray diffraction show that together with the garnet fase Y0 ,15Zr0,85O1,93 and Y2Sn2O7 are formed, the latter having pyrochlore structure. It was demonstarted that the introduct ion of Cr(III) in the mantioned pyrochlore structure results in the formati on of a red- violet pigment. Finally, the sinthesized fases were checked as pigments using an industrial transparent boron containing frit. The tin co ntaining pigments demonstrated good pigmenting ability and stability at 108 0 degreesC.