Development of an iridium-tantalum modified aluminide coating as a diffusion barrier on nickel-base single crystal superalloy TMS-75

F. Wu, Hideyuki Murakami, A. Suzuki

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

An iridium-tantalum modified aluminized (Ir-Ta-Al) coating obtained by a two-step process is investigated. Ir-71 at.% Ta alloy was first coated on a nickel-base single-crystal superalloy TMS-75 by an electron beam physical vapor deposition (EB-PVD), and the resultant Ir-Ta alloy coating on the TMS-75 was treated by a conventional low-activity pack-cementation aluminizing process. It is found that a triplex layer structure, Ir-Ta alloy layer/β-NiAl/Al-diffusion zone, is formed in the order from the surface. In order to assess the oxidation resistance of the coated material, cyclic oxidation tests were carried out at 1373 K in air. It is found that Ir-Ta-Al coated TMS-75 had better thermal cyclic oxidation resistance than simply aluminized TMS-75. The microstructural evolution caused by the interdiffusion of solute elements shows remarkable difference on the precipitation of detrimental phases such as topologically close-packed (TCP) phase. The precipitation of TCP phase in the Ir-Ta-Al-coated TMS-75 was limited only within 180 μm in depth from the surface, whereas in the simply aluminized TMS-75, such detrimental phases were precipitated to the depth of more than 300 μm from the surface, indicating that the Ir-Ta-Al coating functions as an effective diffusion barrier for the alloying elements.

Original languageEnglish
Pages (from-to)62-69
Number of pages8
JournalSurface and Coatings Technology
Volume168
Issue number1
DOIs
Publication statusPublished - 2003 May 1
Externally publishedYes

Fingerprint

Tantalum
Iridium
Diffusion barriers
heat resistant alloys
tantalum
iridium
Nickel
Superalloys
Single crystals
nickel
coatings
Coatings
oxidation resistance
single crystals
Oxidation resistance
aluminum coatings
Coated materials
cementation
Microstructural evolution
Physical vapor deposition

Keywords

  • Aluminized coating
  • Diffusion barrier
  • EB-PVD
  • Ir-Ta alloy
  • Ni-base superalloy

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

@article{bb73d2caa03d4fdf8e8f990309cf01c8,
title = "Development of an iridium-tantalum modified aluminide coating as a diffusion barrier on nickel-base single crystal superalloy TMS-75",
abstract = "An iridium-tantalum modified aluminized (Ir-Ta-Al) coating obtained by a two-step process is investigated. Ir-71 at.{\%} Ta alloy was first coated on a nickel-base single-crystal superalloy TMS-75 by an electron beam physical vapor deposition (EB-PVD), and the resultant Ir-Ta alloy coating on the TMS-75 was treated by a conventional low-activity pack-cementation aluminizing process. It is found that a triplex layer structure, Ir-Ta alloy layer/β-NiAl/Al-diffusion zone, is formed in the order from the surface. In order to assess the oxidation resistance of the coated material, cyclic oxidation tests were carried out at 1373 K in air. It is found that Ir-Ta-Al coated TMS-75 had better thermal cyclic oxidation resistance than simply aluminized TMS-75. The microstructural evolution caused by the interdiffusion of solute elements shows remarkable difference on the precipitation of detrimental phases such as topologically close-packed (TCP) phase. The precipitation of TCP phase in the Ir-Ta-Al-coated TMS-75 was limited only within 180 μm in depth from the surface, whereas in the simply aluminized TMS-75, such detrimental phases were precipitated to the depth of more than 300 μm from the surface, indicating that the Ir-Ta-Al coating functions as an effective diffusion barrier for the alloying elements.",
keywords = "Aluminized coating, Diffusion barrier, EB-PVD, Ir-Ta alloy, Ni-base superalloy",
author = "F. Wu and Hideyuki Murakami and A. Suzuki",
year = "2003",
month = "5",
day = "1",
doi = "10.1016/S0257-8972(03)00009-4",
language = "English",
volume = "168",
pages = "62--69",
journal = "Surface and Coatings Technology",
issn = "0257-8972",
publisher = "Elsevier",
number = "1",

}

TY - JOUR

T1 - Development of an iridium-tantalum modified aluminide coating as a diffusion barrier on nickel-base single crystal superalloy TMS-75

AU - Wu, F.

AU - Murakami, Hideyuki

AU - Suzuki, A.

PY - 2003/5/1

Y1 - 2003/5/1

N2 - An iridium-tantalum modified aluminized (Ir-Ta-Al) coating obtained by a two-step process is investigated. Ir-71 at.% Ta alloy was first coated on a nickel-base single-crystal superalloy TMS-75 by an electron beam physical vapor deposition (EB-PVD), and the resultant Ir-Ta alloy coating on the TMS-75 was treated by a conventional low-activity pack-cementation aluminizing process. It is found that a triplex layer structure, Ir-Ta alloy layer/β-NiAl/Al-diffusion zone, is formed in the order from the surface. In order to assess the oxidation resistance of the coated material, cyclic oxidation tests were carried out at 1373 K in air. It is found that Ir-Ta-Al coated TMS-75 had better thermal cyclic oxidation resistance than simply aluminized TMS-75. The microstructural evolution caused by the interdiffusion of solute elements shows remarkable difference on the precipitation of detrimental phases such as topologically close-packed (TCP) phase. The precipitation of TCP phase in the Ir-Ta-Al-coated TMS-75 was limited only within 180 μm in depth from the surface, whereas in the simply aluminized TMS-75, such detrimental phases were precipitated to the depth of more than 300 μm from the surface, indicating that the Ir-Ta-Al coating functions as an effective diffusion barrier for the alloying elements.

AB - An iridium-tantalum modified aluminized (Ir-Ta-Al) coating obtained by a two-step process is investigated. Ir-71 at.% Ta alloy was first coated on a nickel-base single-crystal superalloy TMS-75 by an electron beam physical vapor deposition (EB-PVD), and the resultant Ir-Ta alloy coating on the TMS-75 was treated by a conventional low-activity pack-cementation aluminizing process. It is found that a triplex layer structure, Ir-Ta alloy layer/β-NiAl/Al-diffusion zone, is formed in the order from the surface. In order to assess the oxidation resistance of the coated material, cyclic oxidation tests were carried out at 1373 K in air. It is found that Ir-Ta-Al coated TMS-75 had better thermal cyclic oxidation resistance than simply aluminized TMS-75. The microstructural evolution caused by the interdiffusion of solute elements shows remarkable difference on the precipitation of detrimental phases such as topologically close-packed (TCP) phase. The precipitation of TCP phase in the Ir-Ta-Al-coated TMS-75 was limited only within 180 μm in depth from the surface, whereas in the simply aluminized TMS-75, such detrimental phases were precipitated to the depth of more than 300 μm from the surface, indicating that the Ir-Ta-Al coating functions as an effective diffusion barrier for the alloying elements.

KW - Aluminized coating

KW - Diffusion barrier

KW - EB-PVD

KW - Ir-Ta alloy

KW - Ni-base superalloy

UR - http://www.scopus.com/inward/record.url?scp=0037403398&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037403398&partnerID=8YFLogxK

U2 - 10.1016/S0257-8972(03)00009-4

DO - 10.1016/S0257-8972(03)00009-4

M3 - Article

AN - SCOPUS:0037403398

VL - 168

SP - 62

EP - 69

JO - Surface and Coatings Technology

JF - Surface and Coatings Technology

SN - 0257-8972

IS - 1

ER -