摘要
The stratified gradient thermal barrier coatings (TBCs) were obtained by laser cladding of ZrO 2 and NiCoCrAlY mixture powder. The coatings were four layer structure: cellular dendritic ZrO 2, dense ZrO 2, Ni based alloy bonding coating and substrate. The formation of the stratified TBCs was attributed to the insolubility of ZrO 2 in the Ni based alloy and the lower density of ZrO 2 than that of Ni based alloy when both of them were in melted condition. The formation of two layered ZrO 2 was related to the presence of Al in the Ni based alloy, i) Al could be preoxidized into Al 2O 3 that could be segregated in the grain boundaries of ZrO 2 during solidification process; ii) Al could be partially preoxidized into Al 2O 3, then Al and Al 2O 3 could be segregated simultaneously at the grain boundaries of ZrO 2 during solidification process. Two formation processes were presented.
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 Ni-based 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.
出处
《中国有色金属学会会刊:英文版》
CSCD
2000年第1期92-93,共2页
Transactions of Nonferrous Metals Society of China