Mapping chemical properties of advanced materials using imaging Raman spectroscopy

Partially stabilized zirconia (PSZ) is a microengineered material in which a phase transformation from tetragonal to monoclinic occurs in the stress field surrounding a crack. This transformed zone inhibits further crack growth, thus toughening the material. A complete understanding of the toughening mechanism relies upon a precise measurement of the zone parameters.1 Measurement of the zone parameters requires a spatially resolved technique sensitive to martensitic phase changes in which the atomic composition is unchanged. Raman spectroscopy is a sensitive technique in applications where non-destructive chemical analysis is desired. Spatially resolved Raman spectroscopy where up to 1000 adjacent spatial elements are collected and analyzed simultaneously is possible using a two-dimensional detector and appropriate collection optics and analysis software.2 The spatial resolution, determined by the detector’s spatial resolution and the magnification of the collection optics, can approach 2 μm. Translating the sample in one dimension allows a 2-D map of the chemical composition to be produced efficiently.