Reaction sintered zirconium titanate-zirconia bulk materials from 3Y2O3-stabilized zirconia and TiO2. Phase composition and their potential for thermal shock applications

This work evaluates the potential of zirconium titanate-zirconia composites for thermal shock. Materials with Zr0.97Y0.03O1.985:TiO2 molar ratios 50:50 (Z(Y)T50) and 70:30 (Z(Y)T70) were obtained from Y2O3 (3 mol%)-stabilized ZrO2 and TiO2 mixtures colloidal processed and reaction sintered at 1773 K with low cooling rate (2-5 K/min). The crystalline phases and their unit cell parameters were determined by Rietveld analysis of high resolution X-ray diffraction patterns. The zirconium titanate phase in these materials is o-TiZrO4, being the major phase in Z(Y)T50 in which c-ZrO2 is secondary phase. Z(Y)T70 has t-ZrO2 as main phase, o-TiZrO4 as secondary phase and c-ZrO2 and m-ZrO2 as minor phases. The Hasselman thermal shock resistance factors, calculated using the experimental values of the involved properties, Young's modulus, thermal expansion coefficient, and fracture strength, have demonstrated the high potential of zirconia-zirconium titanate composites for thermal shock applications in oxidizing atmospheres.