Lateral growth kinetics of alpha-alumina accompanying the formation of a protective scale on (111)NiAl during oxidation at 1100 degrees C Academic Article uri icon

abstract

  • During the early stages of oxidation of (111) NiAl at 1100C, an alumina scale forms and undergoes a series of allotropic phase transformations. In the final stages of phase development, the metastable -alumina transforms to the equilibrium -alumina phase. Images formed using the photoluminescence from trace Cr3+ impurities in the scale, in conjunction with scanning electron microscopy, indicate that the -alumina forms by a nucleation and growth process within the -alumina matrix. Lateral impingement of the growing -alumina islands coincides with the reported drop in oxidation kinetics to those characteristic of long-term oxidation of NiAl. Unlike most interface-controlled transformations, the kinetics of the to transformation in the lateral growth are found to be logarithmic. Possible causes of these unusual kinetics are proposed.

published proceedings

  • APPLIED PHYSICS LETTERS

altmetric score

  • 3

author list (cited authors)

  • Lipkin, D. M., Schaffer, H., Adar, F., & Clarke, D. R.

citation count

  • 85

complete list of authors

  • Lipkin, DM||Schaffer, H||Adar, F||Clarke, DR

publication date

  • May 1997