INVESTIGATION OF THE PHASE-COMPOSITION IN SINTERED LANTHANA-DOPED (ZR,SN) TIO4 CERAMICS

Ceramic materials of the ZrO2-SnO2-TiO2 system, modified by La2O3 and ZnO additions, were investigated by X-ray diffraction, scanning electr on microscopy and energy-dispersive X-ray spectrometry. All the sample s sintered at 1330, 1360 and 1400-degrees-C contain a (Zr(x)Sn(z))TiO4 (x+z = 1, 0 < z less-than-or-equal-to 0.4) solid solution coexisting with ZrTiO4, the last gradually disappearing with rising temperature. At 1400-degrees-C, the (Zr0.8Sn0.2)TiO4 solid solution matrix was not quite homogeneous, containing small amounts of a grain-boundary phase assumed to be La2(Zr,Sn,Ti)2O7 and the expected TiO2-basis solid solut ion rich in Zn and La. The evolution of the chemical composition of (Z r(x)Sn(z))TiO4 solid solution to (Zr0.8Sn0.2)TiO4 and the simultaneous disappearance of ZrTiO4 are thought to explain the variation trends o f lattice parameters with increasing sintering temperature.