Effect of quaternary additions on the oxidation behavior of Hf-doped NiAl

B. A. Pint, K. L. More, I. G. Wright

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

Cast model alloys, based on β-NiAl + 0.05at.%Hf, were used to study the effects on oxidation behavior of elements that are commonly present in low-activity aluminide bond coatings on single-crystal, Ni-base superalloys. Single additions of Re, Ti, Ta, and Cr were examined in cyclic and isothermal exposures at 1100 to 1200°C in order to determine their effect on the oxide growth rate and resistance to scale spoliation. With 1 at. % additions, all of these elements were found to be detrimental to the oxidation performance of the base NiAl + Hf alloy. Additions of Re and Cr were found to form second-phase precipitates in the alloy, which appeared to lead to scale spallation, while additions of Ti and Ta were internally oxidized and incorporated into the scale as grain-boundary segregants. These results suggest that it is necessary to minimize the levels of these types of elements that enter Hf-modified aluminide coatings by using process modifications or a diffusion barrier.

Original languageEnglish
Pages (from-to)257-283
Number of pages27
JournalOxidation of Metals
Volume59
Issue number3-4
DOIs
StatePublished - Apr 2003

Funding

The authors would like to thank G. Garner, L. D. Chitwood, L. Walker, and K. S. Trent for assistance with the experimental work. P. F. Tortorelli, J. R. DiStefano, and J. A. Haynes provided helpful comments on the manuscript. This research was sponsored by the U.S. Department of Energy, Advanced Turbine Systems program under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

Keywords

  • Bond coats
  • Hafnium
  • High-temperature oxidation
  • NiAl
  • Reactive-element effect

Fingerprint

Dive into the research topics of 'Effect of quaternary additions on the oxidation behavior of Hf-doped NiAl'. Together they form a unique fingerprint.

Cite this