| Popis: |
Ceramic samples with the compositions 97mol% ZrO2, 3mol% Yb2O3; 96mol% ZrO2, 3mol% Yb2O3,1mol%SrO;96mol% ZrO2, 3mol% Yb2O3,1mol% СаОwere obtained by the sol-gel method. The final sintering was carried out at 1450 or 1550°C. A comparative study of the samples was carried out by the Rietveld method using X-ray diffraction data. The Stephens's approach was used to model the diffraction peaks profiles. The addition of SrO and CaO promotes the formation of thet'form during sintering of the samples at 1450°C. These samples contain thetform (70vol%) andt'form (30vol%). The samples sintered at 1550°C without doping and doped with SrO have approximately the same phase composition. In the samples sintered at 1550°C with the addition of CaO, the content of thet'form is 45vol%, and the content of thetform is 55vol%. The addition of CaO or SrO leads to an increase in the unit cell volumes of thetforms during sintering at 1450°C.For the samples sintered at 1550°C, the unit cell volumes of thetforms are less than for the samples without doping. Based on the Williamson-Hall plots for thetforms, it was found that the CaO and SrO doping reduces the microstrain values for the [001] crystallographic direction. |
Full Text from ScienceDirect