TY - JOUR
T1 - Influence of surface roughness on the oxidation behavior of a Ni-4.0Cr-5.7Al single crystal superalloy
AU - Pei, Haiqing
AU - Wen, Zhixun
AU - Li, Zhenwei
AU - Zhang, Yamin
AU - Yue, Zhufeng
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/5/15
Y1 - 2018/5/15
N2 - The high-temperature oxidation dynamics and mechanisms of a Ni-based single crystal superalloy with four kinds of surface roughnesses were investigated by virtue of XRD, OM, SEM and EDS at 1000 °C. In the initial oxidation stage, outer (Ni, Co)O was mainly produced on the surfaces of the samples with Ra = 90 nm and 19 nm. Correspondingly, outer Cr 2 O 3 and transient θ-Al 2 O 3 were mainly formed on the surfaces with Ra = 509 nm and 182 nm. After 180 min oxidation, the values of instantaneous parabolic mass gain coefficients (k p ) of the samples with all surface roughnesses were gradually consistent with the data of the growth parabolic coefficient of α-Al 2 O 3 . The oxidation mechanisms of Ni-based superalloy with different surface roughnesses were discussed by a model. The external diffusion flux of Al (D Al ) increases with the increases of surface roughness. Thus, the required Al concentration decreases with the increases of surface roughness when the selective oxidation of Al occurrs to form a protective single α-Al 2 O 3 film.
AB - The high-temperature oxidation dynamics and mechanisms of a Ni-based single crystal superalloy with four kinds of surface roughnesses were investigated by virtue of XRD, OM, SEM and EDS at 1000 °C. In the initial oxidation stage, outer (Ni, Co)O was mainly produced on the surfaces of the samples with Ra = 90 nm and 19 nm. Correspondingly, outer Cr 2 O 3 and transient θ-Al 2 O 3 were mainly formed on the surfaces with Ra = 509 nm and 182 nm. After 180 min oxidation, the values of instantaneous parabolic mass gain coefficients (k p ) of the samples with all surface roughnesses were gradually consistent with the data of the growth parabolic coefficient of α-Al 2 O 3 . The oxidation mechanisms of Ni-based superalloy with different surface roughnesses were discussed by a model. The external diffusion flux of Al (D Al ) increases with the increases of surface roughness. Thus, the required Al concentration decreases with the increases of surface roughness when the selective oxidation of Al occurrs to form a protective single α-Al 2 O 3 film.
KW - External diffusion flux of Al
KW - Ni-based single crystal superalloy
KW - Oxidation mechanism
KW - Protective α-Al O film
KW - Surface roughness
UR - http://www.scopus.com/inward/record.url?scp=85041395068&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2018.01.226
DO - 10.1016/j.apsusc.2018.01.226
M3 - 文章
AN - SCOPUS:85041395068
SN - 0169-4332
VL - 440
SP - 790
EP - 803
JO - Applied Surface Science
JF - Applied Surface Science
ER -