Diffusion processes in Al2O3 scales - Void growth, grain growth, and scale growthThe internal microstructure and growth kinetics of Al2O3 scales on Ni-15Cr-13Al (wt percent) are investigated by TEM and analyzed in relation to models of diffusivity. Polished arc-melted specimens were oxidized in 1-atm air at 1100 C for 0.1, 1.0, and 20 hours and ion-thinned for TEM at 100 kV. The frequency distribution of void size and grain size is determined for different oxidation times and scale depths. The kinetics of microvoid growth and of grain and scale growth are plotted and related via simplified models to lattice and grain-boundary oxygen diffusivity, respectively. Good agreement is found between model predictions and data obtained by Oishi and Kingery (1960) on oxygen diffusion in bulk Al2O3. The further implications and limitations of these findings are discssed.
Document ID
19830061020
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Smialek, J. L. (NASA Lewis Research Center Materials Div., Cleveland, OH, United States)
Gibala, R. (Case Western Reserve University Cleveland, OH, United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1983
Subject Category
Metallic Materials
Meeting Information
Meeting: High temperature corrosion; International Conference