Concentration profiles through thin oxide scales by ion-probe microanalysis

The ion microanalyzer has been used to measure concentration profiles through oxide scales formed on oxide dispersion-containing Ni-20 wt pct Cr alloys after high-temperature oxidation. These protective scales are sufficiently thin, generally less than 1.0 μm, to render examination by more established techniques such as electron-probe microanalysis difficult and often fruitless. The operation of the technique is described and the results obtained are discussed. Although the analyses are not yet quantitative, the profiles obtained indicate that the dispersoid is incorporated throughout the whole thickness of the scales, and allow further insight into the mechanism of oxidation of these alloys.