THE EFFECT OF SINTERING TEMPERATURE ON THE 3Y-TZP CO-DOPED WITH EQUIMOLAR ADDITION OF THE YTTRIA AND NIOBIA

摘要

The aim of this work is to identify the better sintering temperature to density zirconia co-doped with yttria and niobia and to verify the existence of the stable tetragonal phase (f) under applied stress at room temperature to be applied as a TBC material. Four compositions with equimolar addition of yttria and niobia in the 3Y-TZP were produced, 13.0 %, 14.5 %, 16.0 % and 17.5 %. The mixtures were prepared in high energy ball milling for 10 minutes and the samples prepared on uniaxial and isostatic pressing. The selected sintering temperatures were 1500°C, 1550°C, 1600°C and 1650°C, for 1 hour. Analysis of conventional and high resolution X-Ray Diffraction and measures of specific mass by Archimedes method were performed. Through measures of the specific mass, the best sintering temperature was 1550°C, with relative specific mass above 95 %. The x-ray diffraction analysis indicate a probable existence of t' in all samples.