热喷涂热障涂层的热生长氧化层的生长和演变

Growth and evolution of thermally grown oxides in thermal barrier coating produced by thermal spraying

用大气等离子热喷涂工艺在镍基高温合金GH4169表面制备热障涂层的粘结层和陶瓷层。采用X射线衍射（XRD）、扫描电子显微镜（SEM）和Cr^（3＋）荧光光谱表征热障涂层的热生长氧化物（TGO）的物相、生长形貌与氧化铝相变的演化。研究表明,经1050℃高温氧化后,热障涂层的TGO生长服从幂指数函数规律。TGO的主要物相为Al_2O_3、Cr_2O_3和NiCr_2O_4;1050℃高温氧化300 h后,粘结层逐渐贫铝,导致Ni与已经形成的Al_2O_3反应生成尖晶石相,由于大量的Cr^（3＋）参与了加速TGO相变的过程,导致Cr含量下降。

Thermal barrier coatings were prepared on the nickel-base superalloy GH4169 substrate by thermal spraying process. Both thebond coating and the top coating were produced by air plasma spraying. The phase, growth morphology and elemental variation of thermallygrown oxides （TGO） were characterized by means of X-ray diffraction, scanning electron microscope and Cr3＋ luminescence spectroscopy.The results show that after isothermal oxidation at 1050 qC, the growth rate of TGO basically confirms with the power function growth and theTGO contains A1203 , Cr203 and NiCr204. After isothermal oxidation at 1050 ℃ for 300 h, the deletion of aluminum appears inside the bondcoating, which results in the oxidation of nickel and then react with A1203 to produce spinel. Meantime, the content of chromium decreases,which is closely related to the large amount of chromium in the process of accelerating TGO phase transformation.