LaMeAl_(11)O_(19)/YSZ热障涂层热力学性能和热循环寿命  

Thermodynamic Properties and Thermal Cycling Lifetimes of LaMeAl_(11)O_(19)/YSZ Thermal Barrier Coatings

作　　者：蔚海浪 曹学强[1] 邓龙辉[1] 蒋佳宁 WEI Hailang;CAO Xueqiang;DENG Longhui;JIANG Jianing(State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070

出　　处：《无机材料学报》2022年第12期1259-1266,共8页Journal of Inorganic Materials

基　　金：国家自然科学基金重点项目(92060201)。

摘　　要：LaMeAl_(11)O_(19)陶瓷具有独特的晶体结构,优异的热力学性能,低热导率,高温相稳定性等特点,是一类非常有应用前景的热障涂层(TBC)材料。本研究通过大气等离子喷涂(APS)制备了LaMeAl_(11)O_(19)/YSZ(Me=Mg,Cu,Zn)双陶瓷层热障涂层。通过对涂层进行火焰热循环测试并结合扫描电子显微镜、X射线衍射仪等分析技术对涂层进行失效分析。结果表明,LaMgAl_(11)O_(19)(LMA)、LaZnAl_(11)O_(19)(LZA)和LaCuAl_(11)O_(19)(LCA)粉末在等离子喷涂过程中发生了分解,导致三种涂层中磁铅石相含量的差异,从而影响三种涂层的热循环寿命。由于LaMeAl_(11)O_(19)层与YSZ层的热膨胀系数不匹配以及非晶相重结晶产生的体积收缩,LaMeAl_(11)O_(19)层从YSZ层上剥落。YSZ层暴露在高温下,加速了烧结和TGO的生长,又促进了YSZ层剥落。低温下,LaMeAl_(11)O_(19)的热导率随着Me原子序数增加而降低;高温下,与LMA和LZA相比,LCA涂层红外发射率最高(0.88,600℃),削弱了光子传导对热导率的贡献,导致热导率降低,LCA在高温红外辐射涂层中具有潜在的应用价值。LaMeAl_(11)O_(19) ceramics is a kind of thermal barrier coating(TBC)material with promising application prospect due to its unique crystal structure,excellent thermodynamic properties,low thermal conductivity,and high temperature phase stability.Here,LaMeAl_(11)O_(19)/YSZ(Me=Mg,Cu,Zn)thermal barrier coatings were prepared by atmospheric plasma spraying(APS).Failure analysis of the coating was carried out by burner rig test and other analysis techniques.The results show that LaMgAl_(11)O_(19)(LMA),LaZnAl_(11)O_(19)(LZA)and LaCuAl_(11)O_(19)(LCA)powders are decomposed during the plasma spraying,resulting in different contents of magnetoplumbite phase in the coatings,which may be an important factor responsible for their distinction of thermal cycling lifetimes.The LaMeAl_(11)O_(19) layer is delaminated upon YSZ layer due to mismatch of thermal expansion coefficient between LaMeAl_(11)O_(19) layer and YSZ layer and volume shrinkage caused by recrystallization of amorphous phase.Then the YSZ layer is exposed high temperature,accelerating sintering and TGO growth,and promoting the delamination of the YSZ layer from the bond coat.At low temperature,with the increase of the atomic number of the divalent Me2+,the thermal conductivity of the LaMeAl_(11)O_(19) decreases.At high temperature,LCA coating has better infrared emissivity(0.88,600℃)than both LMA and LZA,which weakens the contribution of photon conduction to thermal conductivity and leads to the reduction of thermal conductivity.Therefore,LCA coating has potential application in high temperature infrared radiation coating.

关 键 词：热障涂层 磁铅石型稀土六铝酸盐 火焰热循环 热力学性能 

分 类 号：TB306[一般工业技术—材料科学与工程]