Abstract
The low-pressure plasma spray coating process has been established in the field of gas turbines and is used for parts (turbine blades, duct segments, etc.) which are exposed to corrosive gases at high temperatures. Overlay coatings based on the MCrAlY alloy system (M is Ni, Co or Fe) are commonly employed as oxidation-and corrosion-resistant coatings. Mechanical properties such as fatigue lives, of CoCrAlY coated system were investigated at high-temperature as compared with the uncoated unidirectional solidified CM247LC and single crystal CMSX-2.
Rotational bending fatigue properties of the CoCrAlY coated superalloy at high-temperature(1023 K) showed inferior performance in comparison with the uncoated results. It was because that the high stress due to Young's modulus difference was induced at the coating surface. It was also confirmed that the fatigue lives of CoCrAlY coating could be obtained by the rotational bending test.
