High temperature oxidation behavior of Ni-based superalloy GH202

Journal Article · Mon Aug 15 04:00:00 EDT 2016 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.05.013· OSTI ID:22689574

Cao, Jiangdong ^[1]; Zhang, Junsong ^[1]; Chen, Ruifang; Ye, Yunxia ^[2]; Hua, Yinqun ^[1]

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1. School of Material Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)

The isothermal oxidation kinetic and oxidation behavior of Ni-based superalloy GH202 were investigated at temperatures from 800 °C to 1100 °C. The microstructure of GH202 was characterized by scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD). The composition and morphologies of oxide scales of the surface and cross-section samples were examined by X-ray diffraction (XRD), electron probe microanalysis (EPMA), and SEM combined with energy-dispersive spectroscopy (EDS). The results show that the growth of the oxide scales on GH202 obeyed a parabolic law with an activation energy of 247.8 KJ·mol{sup −1} from 800 °C to 1100 °C. The continuous and dense oxide scales that formed at 800 °C and 900 °C were composed of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and a small amount of TiO{sub 2}. Beneath the oxide scales, aluminum-rich oxides formed along the grain boundaries due to internal oxidation. After treatment at 1000 °C for 150 h, the oxide scale was separated into two layers, the outer layer with sparse holes that was mainly composed of Cr{sub 2}O{sub 3} and TiO{sub 2} and an inner layer of dense Cr{sub 2}O{sub 3}. At 1100 °C for 100 h the outer layer was spalled, due to the looser oxide scale with large blocks of TiO{sub 2} and NiCr{sub 2}O{sub 4} which provided channels for oxygen diffusion. - Highlights: •Isothermal oxidation kinetic of GH202 obeys a parabolic law from 800 °C to 1100 °C. •The activation energy of GH202 is closed to the diffusion activation of Cr{sup 3+}. •The evolution process of oxide scales from 800 °C to 1100 °C is displayed by EPMA. •The oxidation behavior of GH202 is mainly controlled by Cr{sup 3+} and Ti{sup 4+}.

• OSTI ID: 22689574
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 118; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ALUMINIUM
BACKSCATTERING
CHROMATES
CHROMIUM OXIDES
CROSS SECTIONS
DIFFUSION
ELECTRON DIFFRACTION
ELECTRON MICROPROBE ANALYSIS
ELECTRON PROBES
GRAIN BOUNDARIES
HEAT RESISTING ALLOYS
LAYERS
MORPHOLOGY
OXIDATION
OXYGEN
SCANNING ELECTRON MICROSCOPY
TEMPERATURE RANGE 1000-4000 K
TITANIUM OXIDES
X-RAY DIFFRACTION