Effect of specimen thickness on chromia scaling of Ni25Cr in N2–O2–H2O test gases at 1000°C. (January 2015)

• Record Type: Journal Article
• Authors: Hänsel, M.; Turan, E.; Shemet, V.; Grüner, D.; Breuer, U.; Simon, D.; Gorr, B.; Christ, H-J.; Quadakkers, W. J.
• Is Part Of: Materials at high temperatures. Volume 32:Number 1/2(2015)
• Page Start: 160
• Page End: 166
• Publication Date: 2015-01
• Subjects: Ni25Cr, -- Chromia growth, -- Water vapour, -- Oxygen partial pressure, -- Point defects, -- Deformation; Materials at high temperatures -- Periodicals; High temperatures -- Periodicals; 620.1121705
• DOI: 10.1179/0960340914Z.00000000092
• Languages: English
• ISSNs: 0960-3409

Abstract

Abstract : The isothermal oxidation behaviour of a Ni25Cr model alloy was studied using specimens of different thicknesses at 1000°C in dry and wet N2 –1%O2 . The oxidation mechanisms were evaluated using thermogravimetry and SEM/electron backscatter diffraction analyses of oxide scale cross-sections. The oxidation rates decreased with increasing specimen thickness and increasing water vapour additions in the gas. The findings can be explained by considering the effect of H-defects and in-scale stress state on point defect concentrations in the chromia lattice.