引用本文:郭磊,张馨木,杨硕.CMAS、CMAS+NaVO3、CMAS+海盐作用下热障涂层的腐蚀行为与机理[J].中国表面工程,2024,37(1):75~86
GUO Lei,ZHANG Xinmu,YANG Shuo.Corrosion Behavior and Mechanisms of Thermal Barrier Coatings in the Presence of CMAS, CMAS + NaVO3, and CMAS + Sea Salt[J].China Surface Engineering,2024,37(1):75~86
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CMAS、CMAS+NaVO3、CMAS+海盐作用下热障涂层的腐蚀行为与机理
郭磊1,2, 张馨木1, 杨硕3
1.天津大学材料科学与工程学院 天津 300072;2.天津大学天津市现代连接技术重点实验室 天津 300072;3.天津大学分析测试中心 天津 300072
摘要:
环境沉积物(CaO-MgO-Al2O3-SiO2,CMAS)的高温腐蚀已成为航空发动机涡轮叶片热障涂层过早失效的重要原因之一。然而涡轮叶片工作环境复杂,熔盐、海盐常与 CMAS 耦合,一起对热障涂层造成多元复杂腐蚀,但目前关于 CMAS 与盐类的多元耦合腐蚀行为鲜有报道。针对 Y2O3部分稳定 ZrO2(YSZ)热障涂层在 CMAS、CMAS+NaVO3、CMAS+海盐作用下的腐蚀行为进行对比研究。通过 XRD、SEM 等方法对不同条件下腐蚀后的涂层进行表征,并分析热处理温度、腐蚀物种类对腐蚀行为的影响。结果表明:与 CMAS 相比,CMAS+NaVO3、CMAS+海盐会在更低的温度下损伤涂层(1 200 ℃)。 当三种腐蚀物均能完全熔化时(1 250 ℃),CMAS+NaVO3、CMAS+海盐熔体则由于更大的流动性而大量渗入,腐蚀内部涂层。其中,CMAS+海盐熔体在涂层内的渗透性最强,1 250 ℃热处理 4 h 后,渗透深度超过 400 μm。盐类的共存会改变 CMAS 的性质,增强熔体的渗透能力,增加涂层内部甚至底部失效的倾向。研究结果有助于理解盐类与 CMAS 耦合时混合熔体对热障涂层的破坏机理及潜在威胁。
关键词:  热障涂层  CMAS+海盐  CMAS+NaVO3  耦合腐蚀  腐蚀机理
DOI:10.11933/j.issn.1007-9289.20230210001
分类号:TG156;TB114
基金项目:国家自然科学基金(52272070)
Corrosion Behavior and Mechanisms of Thermal Barrier Coatings in the Presence of CMAS, CMAS + NaVO3, and CMAS + Sea Salt
GUO Lei1,2, ZHANG Xinmu1, YANG Shuo3
1.College of Materials Science and Engineering, Tianjin University, Tianjin 300072 , China;2.Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072 , China;3.Center for analysis and Test, Tianjin University, Tianjin 300072 , China
Abstract:
As a key thermal protection technology for aeroengine turbine blades, thermal barrier coatings (TBCs) can significantly improve working temperatures and prolong service lifetimes. The corrosion of environmental sediments (CaO-MgO-Al2O3-SiO2, CMAS) is a significant reason for the premature failure of engine TBCs. The aircraft service environment is complex and often experiences desert, inland, ocean, and other regional environments; some molten salts and sea salts are often coupled with CMAS, which together cause multiple and complex corrosions of TBCs. However, there are few reports on the multivariate coupled corrosion behavior of TBCs in the presence of CMAS and salt. The corrosion behavior of Y2O3 partially stabilized ZrO2 (YSZ) TBCs under the attack of CMAS, CMAS+NaVO3, CMAS+sea salt is studied. After corrosion under different conditions, the coatings are characterized using X-ray diffraction, SEM and other methods, and the effects of temperature and corrosion species on the corrosion behavior are analyzed. The results showed that temperature was an important factor affecting the corrosiveness of CMAS, CMAS+NaVO3, and CMAS+sea salt. Only at high temperatures did the coating undergo obvious damage when the corrosion agent was completely melted. As the temperature increased, the penetration ability of the corrosive agents was further enhanced. The type of corrosive substance is another factor that affects corrosion behavior. Compared with CMAS, CMAS+NaVO3 and CMAS+sea salt damaged the coating at lower temperatures. After holding for 4 h at 1 200 ℃, CMAS cannot completely melt, thus its damage to the coating is limited. It did not interact with or penetrate the coating. However, the CMAS+NaVO3 and CMAS+sea salt melted completely under these conditions. The molten CMAS+NaVO3 and CMAS+sea salt dissolved and penetrated the coating surface, leading to the phase transformation of the YSZ. The penetration of CMAS+sea salt was the most severe. At 1 250 ℃, all the three corrosive substances completely melted and corroded the coatings. However, CMAS and CMAS+NaVO3 exhibited small penetration depths owing to their relatively low fluidity. They mainly remained near the surface of the coating, causing delamination and cracking. In contrast, the molten CMAS+sea salt penetrated the coating in large quantities owing to its greater fluidity. After heat treatment at 1 250 ℃ for 4 h, CMAS+sea salt completely penetrated into the coating, and the penetration depth exceeded 400 μm. Consequently, although the surface stratification of the coatings after CMAS+sea salt corrosion was less evident than that after CMAS corrosion, more phase transitions and cracks appeared in the coating interior. The coexistence of salts changes the properties of CMAS and enhances the permeability of the melt, which enables the mixed melt to corrode the YSZ coating at a lower temperature and has stronger permeability. This poses a serious threat to the interior and bottom of the coating. Multivariate coupled corrosion in complex environments poses a serious threat to TBCs. Among these, the influence of sea salt on the CMAS melt is particularly obvious. The damage mechanism and potential threat of the mixed melt to TBCs when the salt is coupled with CMAS are analyzed and expounded, providing a theoretical basis for developing TBC materials with high resistance to the coupling corrosion of CMAS+salt.
Key words:  thermal barrier coating  CMAS+sea salt  CMAS+NaVO3  coupling corrosion  corrosion mechanism
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