常温酸性腐蚀对热障涂层性能的影响

采用酸性盐雾腐蚀试验对物理气相沉积法制备的热障涂层进行了常温腐蚀,研究了常温酸性盐雾腐蚀对热障涂层的微观形貌以及高温性能的影响.试验结果表明：常温酸性腐蚀使热障涂层表面变得粗糙不平,产生了较大的裂纹.经过150次高温循环氧化后,顶层氧化锆晶粒排列疏松,裂纹进一步扩展,中间层--粘结层氧化速度加快,生成了疏松的TGO层.TGO的体积膨胀效应使得陶瓷/粘结层界面结合力降低,缩短了涂层的使用寿命.

Influence of acidic salt spray corrosion on performance of thermal barrier coatings

In this paper,the thermal barrier coatings(TBCs) prepared by electron beam physical vapor deposition(EB-PVD) was by a acidic salt spray test for certain period.The influence of acidic salt spray corrosion on the microstructure and high-temperature cyclic oxidation behavior of TBCs had been investigated.It was shown that the surface of the TBCs became rougher and there were more and greater cracks on the top-coat than that before the salt spray corrosion.There were more greater cracks on the top-coat after 150 times cyclic oxidation.The bond-coat NiCoCrAlY was oxidated severely and the TGO became loose and discontinuous.The volumetic expansion of the TGO was greater than that of the coating which didn't suffer from the ambient acidic salt spray corrosion.So there was stress concentration in the TGO and resulted in the decrease of the bonding strength between the top-coat and the bond-coat.The ambient-temperature corrosion reduced the lifetime of the coatings.