Dilatometer studies of NiCrAlY coatings

The purpose of this work was to determine if lower thermal expansion bondcoat MCrAlY alloys could be developed for thermal barrier coating (TBC) systems. NiCrAlY coatings applied by plasma spray deposition were studied in the dilatometer for first-cycle sintering and in the thermally stabilized state for thermal expansion. Several different compositions were created and tested. A new composition was developed that has both low thermal expansion and avoids the expansion upsweep at 950 °C, common in current NiCrAlY coatings. Phase analysis of selected coatings was done to explain the control of thermal expansion. Comparisons were made to previous thermal expansion values of other MCrAlY coatings.