Secondary reaction zones in coated 4th generation Ni-based blade alloys

Aya Suzuki*, C. M.F. Rae, M. Yoshida, Y. Matsubara, H. Murakami

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

19 Citations (Scopus)


The morphologies and growth kinetics of the Secondary Reaction Zone (SRZ) formed at the interface between the Pt-Aluminised coating and 4th generation Ni-base superalloy substrates have been investigated. Three alloys with systematically varying Ru content in the range of 2-5wt% were studied. Each alloy was tested using four different surface finishes prior to Pt coating. At the lowest Ru content sporadic formation of SRZ was observed, whilst in the higher Ru-containing alloys a continuous SRZ was formed. These alloys also showed more rapid SRZ growth, regardless of the original surface finish. The precipitation of TCPs in the substrate inhibited the growth of the SRZ towards the end of the exposure reversing the advantage of early nucleation. The volume fraction of the SRZ formation followed that in the substrate, reducing with Ru content. EBSD analysis revealed that the higher Ru-containing alloys nucleate many more grains of the SRZ but the number of grains adjusts with growth towards a constant grain size. On balance Ru leads to a deeper penetration depth into the substrate.

Original languageEnglish
Number of pages10
Publication statusPublished - 2008
Externally publishedYes
Event11th International Symposium on Superalloys, Superalloys 2008 - Champion, PA, United States
Duration: 2008 Sept 142008 Sept 18


Other11th International Symposium on Superalloys, Superalloys 2008
Country/TerritoryUnited States
CityChampion, PA


  • Microstructure
  • Ni-base alloys
  • PtA1
  • SRZ

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics


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