Formation mechanism of laser-clad gradient thermal barrier coatings
来源期刊：中国有色金属学报(英文版)2000年第1期
论文作者：陈国锋 冯钟潮 梁勇
文章页码：92 - 93
Key words：laser cladding; thermal barrier coatings; formation mechanismsDocument code: A
Abstract: The stratified gradient thermal barrier coatings (TBCs) were obtained by laser cladding of ZrO2 and NiCoCrAlY mixture powder. The coatings were four-layer structure: cellular dendritic ZrO2, dense ZrO2, Ni-based alloy bonding coating and substrate. The formation of the stratified TBCs was attributed to the insolubility of ZrO2 in the Nibased alloy and the lower density of ZrO2 than that of Ni-based alloy when both of them were in melted condition. The formation of two-layered ZrO2 was related to the presence of Al in the Ni-based alloy, i) Al could be preoxidized into Al2O3 that could be segregated in the grain boundaries of ZrO2 during solidification process; ii) Al could be partially preoxidized into Al2O3, then Al and Al2O3 could be segregated simultaneously at the grain boundaries of ZrO2 during solidification process. Two formation processes were presented.
