Stabilization of Cubic Zirconia with Manganese Oxide

Abstract

A directionally solidified eutectic (DSE) of MnO‐ZrO 2 has been investigated using a variety of electron optical techniques. It is found that considerable MnO goes into ZrO 2 to form a substitutional solid solution. About 14 wt% of MnO is soluble in ZrO 2 close to the eutectic temperature. The solubility of ZrO 2 in MnO, however, is quite low, less than 0.50 wt%. Electron diffraction experiments indicate that ZrO 2 (MnO) has the cubic fluorite structure. Diffuse scattering, similar to other cubic zirconias (e.g., CaO, MgO stabilized zirconia), is also observed in manganese‐stabilized zirconia. Diffuse scattering indicates the presence of oxygen vacancies and thus confirms the defect nature of the fluorite structure. Electron energy loss spectrometry (EELS) fine structure analysis of the Mn L 23 edge provided clear evidence that Mn is present as Mn 2+ in Mn‐stabilized cubic ZrO 2 .