A wide range of properties can be achieved in intermetallic coatings applied by gas detonation spraying (GDS). The properties of Fe-40at%Al GDS layers, however, may change when exposed to temperatures exceeding a threshold level. To characterize such changes, Fe-40at%Al GDS coatings were subjected to systematic dilatometric studies in which temperatures were cycled from room temperature to 1180 °C. The investigation revealed both irreversible and reversible phase transitions as described in the paper. Dilatometry measurements obtained from sintered samples made from the same powder are presented for comparison.

This paper investigates the influence of microstructure on the sintering behavior of thermal barrier coatings. A significant difference is observed between coatings with typical microcracks and those with segmentation cracks. Segmented coatings showed a lower sintering rate and little change in pore size distribution after heat treatment. Conventional coatings, on the other hand, showed an increase in pore diameter and in more porous areas, sintering was more pronounced. All coatings had an elastic modulus in the range of 15-20 GPa, which more than doubled after a 10-h heat treatment at 1200 °C. Paper includes a German-language abstract.