| Title |
Microstructural Observation of Scales formed on HVOF-sprayed NiCoCrA1Ir Coatings |
| Authors |
고재황(Go Jae Hwang); 이정혁(Lee Jeong Hyeog); 이동복(Lee Dong Bog) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
NiCoCrAlIr; Thermal barrier coating; High velocity oxy-fuel spraying |
| Abstract |
High velocity oxy-fuel sprayed 34Co-32Ni-22Cr-10Al-0.4Ir coatings were oxidized between 1000 and 1200℃ in air, and the oxide scales were investigated by XRD, SEM/EDS, and EPMA. The unoxidized coatings consisted mainly of γ-Ni_(3)Al, with some y-Ni and a meager amount of Cr_(2)O_(3). The major oxide formed on the coatings was α-Al_(2)O_(3). Additionally, spinels of CoCr_(2)O_(4) and CoAl_(2)O_(4) coexisted. Neither Ni- nor Ir-xoides were detected by XRD owing to thermodynamic nobility that resist oxidation or their small amount in the oxide scale. Iridium seemed to deter the formation of sound oxide scales. (Received November 17, 2003) |