Microstructure, thermal shock resistance and thermal emissivity of plasma sprayed LaMAl11O19 (M = Mg, Fe) coatings for metallic thermal protection systems
Microstructure, thermal shock resistance and thermal emissivity of plasma sprayed LaMAl11O19 (M = Mg, Fe) coatings for metallic thermal protection systems
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DOI：
10.1016/j.apsusc.2013.01.070
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发表时间：
2013-04
影响因子：
6.7
通讯作者：
Hongzheng Liu;J. Ouyang;Zhan-Guo Liu;Yaming Wang
中科院分区：
文献类型：
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作者：
Hongzheng Liu;J. Ouyang;Zhan-Guo Liu;Yaming Wang
以NiCoCrAlYTa为粘结层，在镍基高温合金上等离子喷涂LaMAl 11 O 19（M=Mg、Fe）陶瓷涂层。研究了这两种陶瓷涂层的显微结构、抗热震性和热发射率。LaMAl 11 O 19涂层具有层状叠层结构，主要由磁铅石型六铝酸盐相和非晶相组成。在热循环过程中，非晶相消失，并在1000和1200°C的温度下形成LaAlO 3相。LaMgAl 11 O 19涂层在1000°C和1200°C的热循环次数分别为102和42次; LaFeAl 11 O 19涂层在1000°C和1200°C的热循环寿命分别为87和30次。镍基高温合金的法向光谱发射率在3-14μm波长范围内约为0.2。而LaFeAl_（11）O_（19）涂层的发射率在短波长范围内约为0.7，在7-14μm波长范围内大于0.9。
LaMAl11O19(M=Mg, Fe) ceramic coatings were plasma-sprayed on nickel-based superalloy with NiCoCrAlYTa as the bond coat. The microstructure, thermal shock resistance and thermal emissivity of these two ceramic coatings were investigated. LaMAl11O19coatings exhibit a characteristic of stacked lamellae, and consist mainly of a magnetoplumbite-type hexaaluminate phase and an amorphous phase. During thermal cycling, the amorphous phase disappears and a LaAlO3phase is formed at temperatures of both 1000 and 1200°C. The thermal cycling numbers of LaMgAl11O19coating are 102 at 1000°C and 42 at 1200°C; LaFeAl11O19has a thermal cycling lifetime of 87 at 1000°C and 30 at 1200°C, respectively. Normal spectral emissivity of nickel-based superalloy is about 0.2 over the whole wavelength range of 3–14μm. However, the emissivity of LaFeAl11O19coating is about 0.7 at short wavelengths and above 0.9 in the wavelength range of 7–14μm.