部分非晶化ZrO_2/Y_2O_3基冷喷涂粉末的制备及应用

Preparation and application of partial noncrystallization ZrO_2-based powders for cold spraying by high energy ball milling

采用溶胶-凝胶法结合高能球磨技术制备部分非晶化ZrO_2/Y_2O_3/Ce O_2复合粉末,采用喷雾造粒技术制备ZrO_2基团聚粉体,并尝试采用冷喷涂制备热障涂层(thermal barrier coatings,简称TBCs)。通过SEM、XRD分析Zr O_2基复合粉末的显微形貌、物相组成及非晶化程度,通过激光粒度分析仪及差热扫描量热仪测定球磨粉末的粒度分布范围及玻璃化转变温度。研究表明,随球磨时间延长,复合粉末逐渐细化,非晶含量逐渐升高,其中80 h球磨粉末的玻璃化转变温度及晶化温度分别为720℃及740℃,过冷液相区宽度达20℃,平均粒度约0.27μm,结晶度约28.09%。喷雾造粒ZrO_2基团聚粉体平均粒度约为32μm,流动性约26.5 s/25 g,松比约1.3 g/cm^3,适合用于冷喷涂沉积涂层。冷喷涂TBCs为致密颗粒状结构,且YSZ顶层与NiCoCrAlY过渡层界面结合紧密。

Partially non-crystallized ZrO2/Y2O3/CeO2composite powder was prepared by sol-gel method and high energy ball milling.ZrO2-based agglomerated powder was fabricated by spray drying,and the thermal barrier coatings(TBCs)were prepared by cold spraying using the powder.The microstructure,phase constitution and amorphous degree of ZrO2-based composite powder and coating were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).Laser particle size analyzer and differential thermal analyzer(DTA)were used to characterize particle size distribution and glass-transition temperature of ZrO2-based ball milled powders.The results show that,ZrO2-based powder is gradually refined and amorphous content gradually increases with increasing ball milling time.The glass-transition temperature and crystallization temperature of80h ball milled powder(with supercooled liquid region of about20℃)are720℃and740℃,respectively.The average particle size and crystallinity are0.27μm and28.09%,respectively.The average particle size,flowability and loose density of ZrO2-based agglomerated powder after spray drying are about32μm,30.5s/25g and1.3g/cm3,respectively.The ZrO2/Y2O3/CeO2composite powder can be used for cold spraying.TBCs fabricated by cold spraying is shown as dense granular structure with tight bonding being found at interface of YSZ top coating and NiCoCrAlY bond coating.