Effect of physical vapor deposited Al2O3 film on TGO growth in YSZ/CoNiCrAlY coatings
Effect of physical vapor deposited Al2O3 film on TGO growth in YSZ/CoNiCrAlY coatings
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DOI：
10.1016/j.ceramint.2012.03.014
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发表时间：
2012-08
影响因子：
5.2
通讯作者：
L. Yanjun;Y. Xie;Liping Huang;Xuanyong Liu;Xuebin Zheng
中科院分区：
文献类型：
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作者：
L. Yanjun;Y. Xie;Liping Huang;Xuanyong Liu;Xuebin Zheng
由氧化钇稳定的氧化锆（YSZ）陶瓷顶层和CoNiCrAlY金属粘结层组成的热障涂层（TBC）已广泛应用于燃气轮机。然而，在热障涂层热暴露过程中，在顶层和粘结层界面处形成的氧化物层往往导致系统的破坏。为了抑制热障涂层氧化层的生长，提高热障涂层的抗热震性能，采用物理气相沉积（PVD）技术在CoNiCrAlY粘结层上预沉积一层Al 2 O3薄膜。采用扫描电子显微镜（SEM）和能谱仪（EDS）研究了常规和预沉积Al 2 O3薄膜热障涂层热暴露后热生长氧化物（TGO）层的形貌和相组成。使用显微拉曼光谱（LabRam-1B）分析涂层中的残余应力。结果表明，常规热障涂层中形成的TGO层主要由Al 2 O3、（Cr，Al）2 O3+（Co，Ni）（Cr，Al）2 O 4 +NiO（CSN）和（Cr，Al）2 O3+（Co，Ni）（Cr，Al）2 O 4（CS）组成，而处理后的热障涂层中形成的TGO层更加均匀致密。通常被认为是TBCs的弱点的CSN和CS簇非常有限。在热障涂层中沉积Al 2 O3薄膜也降低了热冲击后的残余应力。
Thermal barrier coatings (TBCs) comprising of yttria stabilized zirconia (YSZ) ceramic top coat and CoNiCrAlY metallic bond coat have been widely used in gas turbines. However, the developed oxides layer in the interface of the top and bond coats during thermal exposure of the TBCs always results in the destruction of the system. In order to restrain the growth of oxides layer and improve the thermal shock resistance of TBCs, a thin Al2O3film was pre-deposited on CoNiCrAlY bond coat by physical vapor deposition (PVD) technology. After thermal exposure, morphologies and phase compositions of the thermal growth oxides (TGO) layer in the conventional and pre-deposited Al2O3film TBCs were examined by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). The residual stresses in the coatings were analyzed using micro-Raman spectroscopy (LabRam-1B). It was found that TGO layer formed in the conventional TBCs was mainly composed of Al2O3, (Cr,Al)2O3+(Co,Ni)(Cr,Al)2O4+NiO (CSN), and (Cr,Al)2O3+(Co,Ni)(Cr,Al)2O4(CS), while in the treated TBCs, the formed TGO layer appeared more uniform and compact. The CSN and CS clusters, which are normally considered as a weakness for TBCs, were greatly limited. The residual stresses in the TBCs after thermal shock were also reduced by the deposition of Al2O3film.