Spatially Resolved Raman Spectroscopy Study of Transformed Zones in Magnesia‐Partially‐Stabilized Zirconia

Raman vibrational spectroscopy provides an effective phase characterization technique in materials systems containing particle dispersions of the tetragonal and monoclinic polymorphs of zirconia, each of which yields a unique Raman spectrum. An investigation is reported to assess a novel, spatially resolved Raman spectroscopy system in the study of transformed zones surrounding cracks in partially stabilized MgO–ZrO 2 (PSZ). The experimental arrangement uses an imaging (two‐dimensional) photomultiplier tube to produce a one‐dimensional Raman profile of phase compositions along a slitlike laser beam without translation of either the sample or the laser beam and without scanning the spectrometer. For the present optical configuration, the spatial resolution is estimated to be equivalent to the detector resolution of 28 pm and does not appear to be reduced because of secondary scattering events in the PSZ. Results from phase characterization studies of the size, frontal morphology, and extent of transformation of transformation zones surrounding cracks produced under monotonic and cyclic loading conditions are presented. Particularly large zones are observed in the peak‐toughened material, extending 1300 μm ahead of the crack tip with widths of up to 3000 μm. Good agreement is found with similar results determined using optical interference microscopy.