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 language | English |
|---|---|
| Pages (from-to) | 62-69 |
| Number of pages | 8 |
| Journal | Surface and Coatings Technology |
| Volume | 168 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2003 May 1 |
| Externally published | Yes |
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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
Development of an iridium-tantalum modified aluminide coating as a diffusion barrier on nickel-base single crystal superalloy TMS-75. / Wu, F.; Murakami, Hideyuki; Suzuki, A.
In: Surface and Coatings Technology, Vol. 168, No. 1, 01.05.2003, p. 62-69.Research output: Contribution to journal › Article
}
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 -