Tailoring thermal properties of multi-component rare earth monosilicates
Tailoring thermal properties of multi-component rare earth monosilicates
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DOI：
10.1016/j.actamat.2020.06.012
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发表时间：
2020-08
期刊：
影响因子：
9.4
通讯作者：
M. Ridley;J. Gaskins;P. Hopkins;E. Opila
中科院分区：
文献类型：
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作者：
M. Ridley;J. Gaskins;P. Hopkins;E. Opila
本工作探讨了通过在固溶体中引入多种稀土阳离子来定制稀土单硅酸盐的热导率和热膨胀的可能性。研究了六种稀土单硅酸盐：Sc2 SiO 5，Y2 SiO 5，Nd 2SiO 5，Dy 2SiO 5，Er 2SiO 5和Yb 2SiO 5。四个等摩尔二元阳离子混合物和五个阳离子等摩尔混合物进行了表征。用X射线衍射（XRD）测量热膨胀至1200 °C，并通过热盘技术测量体热导率。混合阳离子系统的线性热膨胀系数（CTE）遵循混合物规则，平均线性CTE在6 - 9 × 10−6/°C之间。钪单硅酸盐显示出较低的线性CTE值以及显着较低程度的CTE各向异性比其他稀土单硅酸盐。热导率被发现通过增加稀土阳离子质量和离子半径的不均匀性低于规则的混合物值，如预期的固溶体的热导率。五阳离子等摩尔RE 2SiO 5（RE=Sc，Y，Dy，Er和Yb）在室温下显示出1.06 W/mK的热导率，表明多组分稀土硅酸盐是新型两用隔热和环境屏障涂层的强有力的候选者。
This work explores the possibility of tailoring the thermal conductivity and thermal expansion of rare earth monosilicates through the introduction of multiple rare earth cations in solid solution. Six rare earth monosilicates are studied: Sc2SiO5, Y2SiO5, Nd2SiO5, Dy2SiO5, Er2SiO5, and Yb2SiO5. Four equimolar binary cation mixtures and a five-cation equimolar mixture were characterized. Thermal expansion was measured up to 1200 °C with X-Ray Diffraction (XRD) and bulk thermal conductivity was measured by Hot Disk technique. The linear coefficient of thermal expansion (CTE) of mixed-cation systems followed a rule of mixtures, with average linear CTEs between 6 - 9 × 10−6/°C. Scandium monosilicate showed a lower linear CTE value as well as a notably lower degree of CTE anisotropy than other rare earth monosilicates. Thermal conductivity was found to decrease below rule of mixtures values through increasing heterogeneity in rare earth cation mass and ionic radii, as expected for the thermal conductivity of solid-solutions. The five-cation equimolar RE2SiO5(RE=Sc, Y, Dy, Er, and Yb) shows a thermal conductivity of 1.06 W/mK at room temperature, demonstrating that multi-component rare earth silicates are strong candidates for novel dual-purpose thermal and environmental barrier coatings.