| Influence of MgO Pre-Calcination on Microstructural
Evolution in Mg-Partially Stabilized Zirconia |
Alfredo Aguilar-Elguezabal, Armando Reyes-Rojas, Hilda Esperanza Esparza-Ponce and Miguel Humberto Bocanegra-Bernal*
Pages : 158-168
DOI: 10.1080/0371750X.2026.2659381 |
| Abstract |
| Zirconia (ZrO2
) stabilized with magnesia (MgO) exhibits excellent mechanical
properties, which are influenced by its thermal history. These arise from phase
formation in partially stabilized zirconia (PSZ), where ZrO2
exists in cubic, tetragonal
and monoclinic phases, stabilized by the addition of MgO. This study examined
Mg-PSZ ceramics with 9.25 and 14.5 mol% MgO, sintered at 1500o
and 1720oC for 3 h
in air, revealing variations in phase composition and microstructure. To assess the
effect of MgO morphology, MgO was added either in its raw form or pre-calcined at
1200oC for 2 h. This pre-treatment aimed to modify the powder characteristics and
enhance densification. Scanning electron microscopy, transmission electron
microscopy, and X-ray diffraction were used to analyse phase transformations during
pressureless sintering. Pre-calcination significantly impacted the density and
microstructure, with the final ceramics reaching 87% to 98% of their theoretical density.
Samples with 14.5 mol% MgO showed predominant cubic phases, consistent with
the 1720oC sintering temperature. It is evident that polygonal MgO-cubic precipitates
form on cubic ZrO2
grains without any post-sintering aging treatment, highlighting
the role of pre-calcined MgO in the microstructural evolution. These results support
the potential of Mg-PSZ ceramics for high-stress engineering applications. |
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