LOW-TEMPERATURE STABILIZATION OF ZIRCONIA BY MN THROUGH CO-PRECIPITATED HYDROXIDE GEL ROUTE

Stabilization of zirconia into cubic phase is achieved by partly subst ituting Zr4+ with Mn4+ ions (5-30 mole %) via hydroxide gel formation and subsequent calcination at 773 K and is supported by XRD and IR dat a. A linear correlation between the lattice parameter and the Mn conte nt confirms the incorporation of Mn into ZrO2. The XPS and TPR results provide some evidence for the presence of Mn4+ ions in these samples which have a surface area of about 100 m2 g-1 and are stable in the cu bic phase up to 973 K. On reduction above 973 K, the cubic phase is st abilized probably by Mn2+ ions.