Crystallization behavior of plasma-sprayed lanthanide magnesium hexaaluminate coatings  

作　　者：Liang-liang Huang Hui-min Meng Jing Tang 

机构地区：[1]Corrosion and Protection Center, University of Science and Technology Beijing

出　　处：《International Journal of Minerals,Metallurgy and Materials》2014年第12期1247-1253,共7页矿物冶金与材料学报（英文版）

基　　金：financially supported by the Fundamental Research Funds for the Central Universities of China (No. FRF-AS-11-015B);the Science Research Program of Beijing Municipal Commission of Education (No. 00012087)

摘　　要：LaMgAl11O19 thermal barrier coatings （TBCs） were prepared by atmospheric plasma spraying. The crystallization behavior of the coatings and the synthesis mechanism of LaMgAl11O19 powders were researched. The results showed that the plasma-sprayed coatings conmined some amorphous phase, and LaMgAl11O19 powders were partially decomposed into Al2O3, LaAlO3, and MgAl2O4 in the plasma spraying process. The amorphous phase was reerystallized at a temperature of approximately 1174.9℃, at which level the decomposed Al2O3, LaAl2O3, and MgAl2O4 reacted again. The resynthesis temperature of LaMgAl11O19 in the plasma-sprayed coatings was lower than that of LaMgAl11O19 in the original raw powders. The synthesis mechanism of LaMgAl11O19 powders can be summarized as follows： during the first part of the overall reaction, La2O3 reacts with Al2O3 to form LaAl2O3 at approximately 900℃, and then LaAl2O3 further reacts with Al2O3 and MgAl2O4 to produce LaMgAl11O19 at approximately 1200℃.LaMgAl11O19 thermal barrier coatings （TBCs） were prepared by atmospheric plasma spraying. The crystallization behavior of the coatings and the synthesis mechanism of LaMgAl11O19 powders were researched. The results showed that the plasma-sprayed coatings conmined some amorphous phase, and LaMgAl11O19 powders were partially decomposed into Al2O3, LaAlO3, and MgAl2O4 in the plasma spraying process. The amorphous phase was reerystallized at a temperature of approximately 1174.9℃, at which level the decomposed Al2O3, LaAl2O3, and MgAl2O4 reacted again. The resynthesis temperature of LaMgAl11O19 in the plasma-sprayed coatings was lower than that of LaMgAl11O19 in the original raw powders. The synthesis mechanism of LaMgAl11O19 powders can be summarized as follows： during the first part of the overall reaction, La2O3 reacts with Al2O3 to form LaAl2O3 at approximately 900℃, and then LaAl2O3 further reacts with Al2O3 and MgAl2O4 to produce LaMgAl11O19 at approximately 1200℃.

关 键 词：thermal barrier coatings HEXAALUMINATES plasma spraying CRYSTALLIZATION 

分 类 号：TG174.4[金属学及工艺—金属表面处理]