ABSTRACT
A neutron powder diffraction investigation has revealed the occurrence of substantial quantities of an orthorhombic (o) zirconia in Mg-PSZ which has been aged at the eutectoid temperature (1440°C) then cooled to 77 K. Though there have been reports of TEM observations of orthorhombic zirconia in very similar materials, this is the first observation of bulk quantities of the o phase in eutectoid aged Mg-PSZ. The neutron diffraction pattern is simpler than those showing orthorhombic in materials aged at sub-eutectoid temperature (1100°C), since there are fewer distinct phases in the material aged at the higher temperature. Refinement from the diffraction pattern confirms the structure (space group Pbc21) previously reported.
