Experimental investigation of phase relations and thermodynamic properties in the ZrO₂–TiO₂ system

Abstract

Phase relations in the ZrO 2 -TiO 2 system were studied experimentally using X-ray diffraction (XRD), scanning electron microscopy combined with dispersive X-ray spectrometry (SEM/EDX) and differential thermal analysis (DTA). The homogeneity ranges of ZrO 2 and TiO 2 , as well as high temperature disordered b-(Zr x Ti 1Àx ) 2 O 4 compound were defined in the temperature range of 1700-2040 K. Temperature and composition of eutectic reaction were measured. The standard enthalpy of formation of the b-ZrTiO 4 compound was obtained using high-temperature oxide-melt solution calorimetry. High temperature heat capacity measurement for the b-ZrTiO 4 compound was performed in the temperature range from 250 K to 1200 K. Thermodynamic description of ZrO 2 -TiO 2 system has been derived based on obtained experimental results and data from literature. K E Y W O R D SGibbs energy of formation, modeling/model, phase equilibria, thermal analysis, thermodynamics 1 | INTRODUCTION ZrO 2 -based ceramic materials are widely applied in industry. The b-ZrTiO 4 is well-known compound in the field of electro-ceramics where it is used in the dielectric resonators and devices for telecommunications.1 b-ZrTiO 4 shows anisotropic thermal expansion and therefore has potential as thermal shock resistance application. In the work of L opez-L opez et al 1 the thermomechanical properties of this compound were investigated and it was proposed for application as a constituent of thermal shock resistance materials. It should be mentioned, materials based on the ZrO 2 -TiO 2 system are of interest due to their applications in electrical and optical devices such as capacitors, piezoelectric sensors, ultrasonic motors, and microwave dielectric resonators. [2][3][4][5][6][7] It is also useful as high-temperature pigments and bi-functional catalyst. 8,9The materials based on Al 2 TiO 5 -ZrTiO 4 -ZrO 2 system are new promising kinds of ceramic composite material with low thermal expansion coefficient and high-temperature stability. 10 The system ZrO 2 -TiO 2 is part of the ZrO 2 -Y 2 O 3 -TiO 2 system which presents interest for thermal barrier coating applications. It was shown that co-doping of ZrO 2 with Y 2 O 3 and TiO 2 resulted in strong stabilization of tetragonal modification of YSZ (Yttria Stibilized Zirconia) which is used as TBC (Thermal Barrier Coating). 11The phase relations in the ZrO 2 -TiO 2 system are important for application in metal matrix composite. High alloyed ductile TRIP-steel (Transformation Induced Plasticity) exhibited extraordinary high values of specific energy absorption due to reinforcing by Mg-PSZ-ceramic (MgO Partially Stabilized Zirconia).12 Since, the Mg-PSZ-ceramic shows a martensitic transformation of tetragonal to monoclinic phase during deformation resulting in additional strength increase in the TRIP-steel. 13 In the work of Weigelt et al, 14 it was shown, that a minor addition of titanium improves the densification of the matrix material and the bonding between the zirconia particles and the TRIP steel ma...

Phase equilibria and materials in the TiO2-SiO2-ZrO2 system: a review

“…The thermodynamically optimized phase diagram of the TiO 2 -ZrO 2 system according to experimental data [98] and data from other authors is shown in Fig. 5d.…”

High‐temperature Mass Spectrometric Study and Modeling of the Thermodynamic Properties of the TiO2‐SiO2‐ZrO2 System

“…To obtain reliable data on the TiO 2 activities in the binary TiO 2 ‐ZrO 2 system, the temperature of the sample vaporization had to be increased. The concentration dependence of the TiO 2 activities at the temperature 2356 K, Figure 7, and its comparison with the corresponding phase diagram of this system [10] suggested the existence of strong positive deviation from the ideal behavior in the concentration range from pure titania to equimolar composition of the TiO 2 ‐ZrO 2 system. As the titanium dioxide content in sample N 3, Table 1, decreased from the initial value of 66.7 mol .…”

“…The determined SiO 2 activity values enabled calculation of the SiO partial pressures at the temperature 1973 K over the samples under study by Equation (10).…”

“…The available literature data on the phase diagrams of the boundary SiO 2 ‐TiO 2 , [2,5,6] SiO 2 ‐ZrO 2 , [7,8] and TiO 2 ‐ZrO 2 [9,10] systems are inconsistent at some points and need further clarification. The phase equilibria in the ternary TiO 2 ‐SiO 2 ‐ZrO 2 system were investigated only in a few papers but even the latest reported study [11] dates back to 1976.…”

Synthesis, Crystal Structure, and Thermophysical Properties of ZrTiO4 Nanoceramics

“…Moreover, despite the fact that the phase formation in the ZrO 2 -TiO 2 system has being studied for a long time [32][33][34][35][36][37][38], but even today information about phase equilibria presented in the literature is not completely agreed (Fig. 1), in particular with respect to the com-position and structure of the compound, which was indicated in the phase diagram by Brown et al [34] for the first time (Fig.…”