摘要
采用电子束物理气相沉积(EB-PVD)在镍基高温合金表面制备了YSZ/NiCoCrAlY双层结构热障涂层,研究了其在熔盐环境下的等温热腐蚀行为。结果表明,涂层在加热过程中发生相变引起体积收缩,导致涂层内部产生微裂纹。熔盐填充涂层内微裂纹和柱状晶间隙,降低了涂层的应变容限,引起涂层内应力升高。同时,熔盐促使热生长氧化层(TGO)碱性溶解,产生疏松多孔的氧化物层,导致TGO层加速增厚。在热应力作用下,疏松层氧化物破碎,最终导致涂层剥落。
YSZ/NiCoCrAlY double-layer thermal barrier coatings（TBCs） were prepared by electron beam physical vapor deposition（EB-PVD） on Ni-base superalloy.The isothermal corrosion behavior of TBCs was investigated in molten salt environment.The results show that volume shrinkage due to phase transformation of the coatings during heating process caused formation of micro-cracks in the TBCs.Micro-cracks and gaps between columnar crystals were filled by molten salt,which degraded the strain tolerance and caused the accumulation of stress in the TBCs.Meanwhile,molten salt promoted basic fluxing of the thermally grown oxide（TGO）,and porous oxide layer is formed,accelerating the growth of TGO layer.Thermal stress caused the porous oxide to break into small fragments,resulting in the spallation of TBCs.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2011年第11期123-127,134,共6页
Transactions of Materials and Heat Treatment
基金
国家重点基础研究发展计划资助(2010CB631200)
