Y-rich oxide distribution in plasma sprayed MCrAlY-coatings studied by SEM with a cathodoluminescence detector and Raman spectroscopy

The presented results of the cathodoluminescence and Raman spectroscopy studies indicate that the type of the Y-rich oxide phases after heat-treatment can be correlated with the content and/or reservoir of metallic Y in the coating. Hence, these analytical methods have potential to be applied as (non-destructive) quality control methods in the manufacturing of MCrAlY-coatings. The distribution of the Y-rich oxide precipitates formed during manufacturing has been shown to affect the growth rate and mechanical stability of the alumina scales during service. Y-oxide distribution in the MCrAlY-coatings, therefore, represents a factor, which influences the lifetime of overlay and TBC-coatings.