High-Temperature Corrosion Behaviors of Ti2AlNb Alloy in Simulated Marine Environment

CHEN Wei, ZHANG Dalu, HU Suying, MA Beiyi, CHEN Yongjun, XIE Zhiwen

doi:10.16577/j.issn.1001-1560.2024.0074

Materials Protection >

2024 , Vol. 57 >Issue 4: 20 - 28

DOI: https://doi.org/10.16577/j.issn.1001-1560.2024.0074

High-Temperature Corrosion Behaviors of Ti₂AlNb Alloy in Simulated Marine Environment

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(School of Mechanical Engineering and Automation, Liaoning Science and Technology University, Anshan 114051, China)

XIE Zhiwen（1979- ）, Ph.D., Professor, Research Focus: High Temperature Corrosion and Protection of Metals, E-mail：xzwustl@126.com

Received date: 2023-08-17

Revised date: 2023-09-29

Accepted date: 2023-10-15

Online published: 2024-04-30

Supported by

Southwest Institute of Technology and Engineering Cooperation Fund (HDHDW5902020103)

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Abstract

In this work, high temperature oxidation tests, high temperature hot salt corrosion tests and high temperature hot salt-water vapor synergistic corrosion tests were designed and used to systematically investigate the high temperature corrosion behavior and mechanism of Ti₂AlNb alloy in simulated marine environments. The phase structure characteristics, microscopic corrosion morphology and corrosion product composition of Ti₂AlNb alloy were comprehensively characterized by XRD, SEM and EDS microscale analysis methods. Results showed that after 400 h of oxidation at 650 ℃, the oxidation weight gain of Ti₂AlNb alloy was only 0.507 mg/cm², and a uniform dense oxide layer with approximately 3 μm thickness was generated in situ on the surface. After 400 h of hot salt corrosion at 650 ℃, the weight gain of Ti₂AlNb alloy was as high as 4.049 mg/cm², and the surface oxide layer was brownish yellow with a thickness of up to 150 μm. Meanwhile, the Cl₂ generated by the mixed salt eutectic reaction during the hot salt test served as a catalytic carrier to accelerate the corrosion degradation of the alloy, and the induced formation of gaseous chlorides and corrosion products(such as NaNbO₃ and Na₂TiO₃) ultimately led to severe cracking and peeling of the oxide layer, resulting in severe overall failure and degradation of the alloy. After 400 h of synergistic corrosion by 650 ℃ hot salt water vapor, the corrosion damage of Ti₂AlNb alloy was further intensified. The water vapor environment led to the corrosion degradation of its surface oxide layer and the formation of HCl, and HCl infiltration further accelerated the degradation of the substrate alloy. In addition, the internal diffusion of mixed salts and the Cl₂ produced by their eutectic reaction reacted with water to form HCl again, and HCl further accelerated the corrosion degradation process of Ti₂AlNb, which further caused the accumulation and detachment of a large number of loose corrosion products. As a result, the strong coupling effect of high-temperature hot salt water vapor seriously threatened the service life of Ti₂AlNb alloy.

Key words： Ti₂AlNb alloy; high temperature oxidation; high temperature hot salt corrosion; high temperature hot salt - water vapor synergistic corrosion; corrosion and degradation mechanism

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CHEN Wei, ZHANG Dalu, HU Suying, MA Beiyi, CHEN Yongjun, XIE Zhiwen . High-Temperature Corrosion Behaviors of Ti₂AlNb Alloy in Simulated Marine Environment[J]. Materials Protection, 2024 , 57(4) : 20 -28 . DOI: 10.16577/j.issn.1001-1560.2024.0074

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