Microstructure and oxidation behavior of pt and ptir diffusion coatings on ni-based single crystal superalloy

Dao Chi Tue, Te Kang Tsao, Akira Ishida, Hideyuki Murakami, Le Thi Hong Lien

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of Ir addition and coating method on the microstructure and oxidation behavior of PtxIr (x = 030 at%) diffusion coatings were investigated. A nickel-based single crystal superalloy UCSX-8 was used as a substrate material, while the coatings were developed by either an electroplating or a paste coating method followed by an annealing heat treatment. The phase identification and microstructure analyses by XRD and SEM/EDS revealed that the alloying of Ir in Pt diffusion coating resulted in the formation of L10 ordered ¡-NiPt2Al structure. Cyclic oxidation tests were carried out at 1423 K in still air in order to investigate the thermal stability and oxidation behavior of the coatings. It was found that Ir can significantly retard the formation of voids in both the coating and substrate. In addition, by replacing electroplating method to the paste coating method, the crack problem due to the brittle feature of electroplated PtIr coatings could be solved. Therefore, the Pt20Ir diffusion coating prepared by the paste-coating method is promising as the bond-coating material due to formation of less voids, no crack and stable Al2O3 on the surface.

Original languageEnglish
Pages (from-to)1671-1678
Number of pages8
JournalMaterials Transactions
Volume61
Issue number8
DOIs
Publication statusPublished - 2020 Aug 1

Keywords

  • Diffusion coating
  • Electroplating
  • Oxidation
  • Paste coating
  • Platinum-iridium

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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