模拟海洋环境Ti2AlNb合金高温腐蚀行为研究

陈伟, 张大路, 胡素影, 马北一, 陈永君, 解志文

doi:10.16577/j.issn.1001-1560.2024.0074

材料保护 >

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

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

研究篇

模拟海洋环境Ti₂AlNb合金高温腐蚀行为研究

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(辽宁科技大学机械工程与自动化学院，辽宁鞍山114051)

解志文（1979-）, 博士，教授，研究方向为金属高温腐蚀与防护，E-mail：xzwustl@126.com

收稿日期: 2023-08-17

修回日期: 2023-09-29

录用日期: 2023-10-15

网络出版日期: 2024-04-30

基金资助

西南技术工程研究所联合基金资助项目 (HDHDW5902020103)

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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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摘要

通过设计高温氧化试验、高温热盐腐蚀试验、高温热盐-水汽协同腐蚀试验，系统开展模拟海洋环境Ti₂AlNb合金的高温腐蚀行为与机理研究。利用XRD、SEM和EDS等微尺度分析表征方法，全面解析Ti₂AlNb合金物相结构特征、微观腐蚀形貌及腐蚀产物成分。研究结果表明，经650℃氧化400 h后，Ti₂AlNb合金的氧化增重仅为0.507 mg/cm²,表面原位生成均匀致密的氧化层，其厚度约3μm。经650℃热盐腐蚀400 h后，Ti₂AlNb合金增重高达4.049 mg/cm²,表面氧化层呈棕黄色且厚度高达150μm。热盐试验过程中混合盐共晶反应产生的Cl₂作为催化载体加速合金腐蚀降解，其诱导形成的气态氯化物及腐蚀产物(如NaNbO₃和Na₂TiO₃)最终导致氧化层的严重开裂和剥落，使合金整体严重失效退化。经650℃热盐-水汽协同腐蚀400 h后，Ti₂AlNb合金的腐蚀损伤进一步加剧，水汽环境导致其表面氧化层腐蚀降解及HCl形成，而HCl内渗进一步加速了基体合金降解。此外，混合盐的内扩散及其共晶反应所产生的Cl₂会与水反应再次形成HCl,而HCl进一步加速Ti₂AlNb腐蚀降解进程，并导致大量疏松腐蚀产物堆积和脱落，即高温热盐-水汽强耦合效应严重威胁Ti₂AlNb合金的服役寿命。

关键词： Ti₂AlNb合金; 高温氧化; 高温热盐腐蚀; 高温热盐-水汽协同腐蚀; 腐蚀与降解机理

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陈伟, 张大路, 胡素影, 马北一, 陈永君, 解志文 . 模拟海洋环境Ti₂AlNb合金高温腐蚀行为研究[J]. 材料保护, 2024 , 57(4) : 20 -28 . DOI: 10.16577/j.issn.1001-1560.2024.0074

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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