Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature
The oxidation performance of a single-phase Pt-modified aluminide coating was assessed in oxidation test at 980 °C in comparison with the single crystal superalloy. The results suggested that the Pt-modified aluminide coating exhibited superior oxidation resistance. During oxidation, the oxide scale...
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doaj-cdd52a036a774501ac1198e15abdd7122021-08-26T13:39:34ZengMDPI AGCrystals2073-43522021-08-011197297210.3390/cryst11080972Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High TemperatureYanyan Li0Shuai Li1Chao Zhang2Na Xu3Zebin Bao4Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62#, Shenyang 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62#, Shenyang 110016, ChinaNational Engineering Laboratory for Marine and Ocean Engineering Power System, No. 703 Research Institute of CSSC, Honghu Road 35#, Harbin 150078, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62#, Shenyang 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62#, Shenyang 110016, ChinaThe oxidation performance of a single-phase Pt-modified aluminide coating was assessed in oxidation test at 980 °C in comparison with the single crystal superalloy. The results suggested that the Pt-modified aluminide coating exhibited superior oxidation resistance. During oxidation, the oxide scale formed on bare alloy changed constantly followed by the constitution of the multi-layer scale structure: An outer scale mainly consisted of Cr<sub>2</sub>O<sub>3</sub> + NiCr<sub>2</sub>O<sub>4</sub> + TiO<sub>2</sub> with scarce protection, and an internal scale mainly consisted of Al<sub>2</sub>O<sub>3</sub>. The thickness of the outer oxide scale increased with time, where the scale became looser and more porous. Meanwhile, the internal scale was discontinuous. Oxygen and nitrogen inwardly diffused into substrate, forming Ta<sub>2</sub>O<sub>5</sub> and TiN particles. In contrast to the complex constitution of oxide scale, a uniform and continuous Al<sub>2</sub>O<sub>3</sub> scale formed on Pt-modified aluminide-coated samples after oxidation at 980 °C for 1500 h, which showed no spallation and cracking. Interestingly, θ-Al<sub>2</sub>O<sub>3</sub> and α-Al<sub>2</sub>O<sub>3</sub> phases remained after such a long oxidation time. It is the relatively lower temperature and the presence of Pt retarded θ-α transformation. The degradation rate from β-NiAl to γ′-Ni<sub>3</sub>Al was very slow in the coating. The various development of oxide scale on the coating and substrate was individually studied.https://www.mdpi.com/2073-4352/11/8/972Pt-modified aluminide coatingalumina scalesingle crystal superalloymicrostructureisothermal oxidation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yanyan Li Shuai Li Chao Zhang Na Xu Zebin Bao |
spellingShingle |
Yanyan Li Shuai Li Chao Zhang Na Xu Zebin Bao Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature Crystals Pt-modified aluminide coating alumina scale single crystal superalloy microstructure isothermal oxidation |
author_facet |
Yanyan Li Shuai Li Chao Zhang Na Xu Zebin Bao |
author_sort |
Yanyan Li |
title |
Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature |
title_short |
Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature |
title_full |
Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature |
title_fullStr |
Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature |
title_full_unstemmed |
Oxidation Behavior and Oxide Transformation of a Pt-Modified Aluminide Coating at Moderate High Temperature |
title_sort |
oxidation behavior and oxide transformation of a pt-modified aluminide coating at moderate high temperature |
publisher |
MDPI AG |
series |
Crystals |
issn |
2073-4352 |
publishDate |
2021-08-01 |
description |
The oxidation performance of a single-phase Pt-modified aluminide coating was assessed in oxidation test at 980 °C in comparison with the single crystal superalloy. The results suggested that the Pt-modified aluminide coating exhibited superior oxidation resistance. During oxidation, the oxide scale formed on bare alloy changed constantly followed by the constitution of the multi-layer scale structure: An outer scale mainly consisted of Cr<sub>2</sub>O<sub>3</sub> + NiCr<sub>2</sub>O<sub>4</sub> + TiO<sub>2</sub> with scarce protection, and an internal scale mainly consisted of Al<sub>2</sub>O<sub>3</sub>. The thickness of the outer oxide scale increased with time, where the scale became looser and more porous. Meanwhile, the internal scale was discontinuous. Oxygen and nitrogen inwardly diffused into substrate, forming Ta<sub>2</sub>O<sub>5</sub> and TiN particles. In contrast to the complex constitution of oxide scale, a uniform and continuous Al<sub>2</sub>O<sub>3</sub> scale formed on Pt-modified aluminide-coated samples after oxidation at 980 °C for 1500 h, which showed no spallation and cracking. Interestingly, θ-Al<sub>2</sub>O<sub>3</sub> and α-Al<sub>2</sub>O<sub>3</sub> phases remained after such a long oxidation time. It is the relatively lower temperature and the presence of Pt retarded θ-α transformation. The degradation rate from β-NiAl to γ′-Ni<sub>3</sub>Al was very slow in the coating. The various development of oxide scale on the coating and substrate was individually studied. |
topic |
Pt-modified aluminide coating alumina scale single crystal superalloy microstructure isothermal oxidation |
url |
https://www.mdpi.com/2073-4352/11/8/972 |
work_keys_str_mv |
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