EFFECT OF ERBIUM OXIDE (Er2O3) AMOUNT ON PHASE STABILITY, SINTERING AND MICROSTRUCTURAL EVOLUTION OF CUBIC ZIRCONIA (c-ZrO2)/ERBIUM OXIDE (Er2O3) NANO COMPOSITES |
Paper ID : 1528-UFGNSM-FULL |
Authors: |
Abstract: |
The effect of Er2O3 amount on phase stability, sintering and microstructural evolution of c-ZrO2/Er2O3 composites was investigated. Specimens containing up to 15 wt% Er2O3 were produced by colloidal processing and pressureless sintering. XRD analysis revealed that only cubic fluorite structure is the crystalline phase present in both c-ZrO2 and Er2O3 doped c-ZrO2 specimens and there were no other diffraction peaks of second phase for all compositions. The lattice parameter of the c-ZrO2 decreased with increasing Er2O3 amount up to 10 wt% and stayed constant after this amount. This result indicated that the Er2O3 addition up to 10 wt% was completely solubilized in the c-ZrO2. After this amount, supersaturated c-ZrO2/Er2O3 solid solution could not solubilize more Er2O3 and thus Er2O3 mostly segregated around grain boundaries as thin layer. The grain size of undoped and Er2O3 doped c-ZrO2 specimens decreased with increasing Er2O3 content up to 5 wt% and almost did not change after this amount. The difference of the grain size in undoped and Er2O3 doped c-ZrO2 specimens can be related to differences in segregation of the solute cations at grain boundaries. The relative density of the specimens increased with increasing sintering temperature and slightly decreased with increasing Er2O3 content. This decrease was probably resulted by the porosities formed in the matrix and around the grain boundaries. Microstructural investigations showed that the grains were aquiaxed, faceted and coarsened in the undoped c-ZrO2. Whereas, the grains were aquiaxed, uniform, more rounded and fined in the Er2O3 doped c-ZrO2 specimens. |
Keywords: |
Cubic zirconia, Erbium oxide, Phase stability, Sintering, Microstructural investigation |
Status : Paper Accepted (Oral Presentation) |