Structural characteristics and high-temperature oxidation behaviour of nano-HfO2-doped thermal barrier coatings
Structural characteristics and high-temperature oxidation behaviour of nano-HfO2-doped thermal barrier coatings
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DOI：
10.1016/j.ceramint.2021.11.063
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发表时间：
2021-11
影响因子：
5.2
通讯作者：
Shuaixin Li;Yuelan Di;Hai-dou Wang;Yun-cai Zhao;Li Wang;Lihong Dong
中科院分区：
文献类型：
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作者：
Shuaixin Li;Yuelan Di;Hai-dou Wang;Yun-cai Zhao;Li Wang;Lihong Dong
热生长氧化物(TGO)在热障涂层系统中的不均匀生长是高温环境下涂层界面开裂失效的重要原因。粘结层中稀土元素的掺杂可以有效地抑制TGO中尖晶石氧化物的形成，提高涂层的高温抗氧化性能。然而，单一的稀土元素对抑制TGO失效的作用有限。采用超音速火焰喷涂技术制备了NiCoCrAlYHf涂层。在1100℃下研究了HfO2掺杂对涂层高温氧化行为和金属元素在涂层中扩散行为的影响。结果表明，纳米HfO2填充了粉末颗粒之间的气孔，提高了涂层的硬度。在高温氧化过程中，Hf和Y形成的氧化物尺寸大，溶解度低，有效地阻碍了Al的扩散。这减缓了尖晶石氧化物的生成，有效地抑制了TGO的生长，抑制了涂层内部裂纹的萌生和扩展，减少了界面拉应力和压应力对涂层的损伤，提高了涂层的高温抗氧化性能。
The uneven growth of thermally grown oxides (TGOs) in thermal barrier coating systems is an important cause of cracking failure at the coating interface in high-temperature environments. The doping of rare earth elements in the bonding layer can effectively inhibit the formation of spinel oxides in the TGO and improve the high-temperature oxidation resistance of the coating. However, a single rare earth element has a limited effect on inhibiting TGO failure. In this study, a NiCoCrAlYHf coating was prepared using a supersonic flame spraying (HVOF) technique. The effects of HfO2doping on the high-temperature oxidation behaviour of the coatings and diffusion behaviour of metallic elements in the coatings were investigated at 1100 °C. The results showed that the nano-sized HfO2filled the pores between the powder particles and improved the hardness of the coating. During the high-temperature oxidation process, the oxides formed by Hf and Y had a large size and low solubility, which effectively blocked the diffusion of Al. This slowed the generation of spinel oxides, effectively inhibited the growth of the TGO, it inhibits the initiation and propagation of cracks within the coating, reduces damage to the coating from tensile and compressive stresses at the interface, and improved the high-temperature oxidation resistance of the coating.